Initial revision

4 files changed, 3100 insertions, 0 deletions

diff --git a/gc/include/private/cord_pos.h b/gc/include/private/cord_pos.h
new file mode 100644
index 0000000..d2b24bb
--- /dev/null
+++ b/gc/include/private/cord_pos.h
@@ -0,0 +1,118 @@
+/* 
+ * Copyright (c) 1993-1994 by Xerox Corporation.  All rights reserved.
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program
+ * for any purpose,  provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is granted,
+ * provided the above notices are retained, and a notice that the code was
+ * modified is included with the above copyright notice.
+ */
+/* Boehm, May 19, 1994 2:23 pm PDT */
+# ifndef CORD_POSITION_H
+
+/* The representation of CORD_position.  This is private to the	*/
+/* implementation, but the size is known to clients.  Also	*/
+/* the implementation of some exported macros relies on it.	*/
+/* Don't use anything defined here and not in cord.h.		*/
+
+# define MAX_DEPTH 48
+	/* The maximum depth of a balanced cord + 1.		*/
+	/* We don't let cords get deeper than MAX_DEPTH.	*/
+
+struct CORD_pe {
+    CORD pe_cord;
+    size_t pe_start_pos;
+};
+
+/* A structure describing an entry on the path from the root 	*/
+/* to current position.						*/
+typedef struct CORD_Pos {
+    size_t cur_pos;
+    int path_len;
+#	define CORD_POS_INVALID (0x55555555)
+		/* path_len == INVALID <==> position invalid */
+    const char *cur_leaf;	/* Current leaf, if it is a string.	*/
+    				/* If the current leaf is a function,	*/
+    				/* then this may point to function_buf	*/
+    				/* containing the next few characters.	*/
+    				/* Always points to a valid string	*/
+    				/* containing the current character 	*/
+    				/* unless cur_end is 0.			*/
+    size_t cur_start;	/* Start position of cur_leaf	*/
+    size_t cur_end;	/* Ending position of cur_leaf	*/
+    			/* 0 if cur_leaf is invalid.	*/
+    struct CORD_pe path[MAX_DEPTH + 1];
+    	/* path[path_len] is the leaf corresponding to cur_pos	*/
+    	/* path[0].pe_cord is the cord we point to.		*/
+#   define FUNCTION_BUF_SZ 8
+    char function_buf[FUNCTION_BUF_SZ];	/* Space for next few chars	*/
+    					/* from function node.		*/
+} CORD_pos[1];
+
+/* Extract the cord from a position:	*/
+CORD CORD_pos_to_cord(CORD_pos p);
+	
+/* Extract the current index from a position:	*/
+size_t CORD_pos_to_index(CORD_pos p);
+	
+/* Fetch the character located at the given position:	*/
+char CORD_pos_fetch(CORD_pos p);
+	
+/* Initialize the position to refer to the give cord and index.	*/
+/* Note that this is the most expensive function on positions:	*/
+void CORD_set_pos(CORD_pos p, CORD x, size_t i);
+	
+/* Advance the position to the next character.	*/
+/* P must be initialized and valid.		*/
+/* Invalidates p if past end:			*/
+void CORD_next(CORD_pos p);
+
+/* Move the position to the preceding character.	*/
+/* P must be initialized and valid.			*/
+/* Invalidates p if past beginning:			*/
+void CORD_prev(CORD_pos p);
+	
+/* Is the position valid, i.e. inside the cord?		*/
+int CORD_pos_valid(CORD_pos p);
+
+char CORD__pos_fetch(CORD_pos);
+void CORD__next(CORD_pos);
+void CORD__prev(CORD_pos);
+
+#define CORD_pos_fetch(p)	\
+    (((p)[0].cur_end != 0)? \
+     	(p)[0].cur_leaf[(p)[0].cur_pos - (p)[0].cur_start] \
+     	: CORD__pos_fetch(p))
+
+#define CORD_next(p)	\
+    (((p)[0].cur_pos + 1 < (p)[0].cur_end)? \
+    	(p)[0].cur_pos++ \
+    	: (CORD__next(p), 0))
+
+#define CORD_prev(p)	\
+    (((p)[0].cur_end != 0 && (p)[0].cur_pos > (p)[0].cur_start)? \
+    	(p)[0].cur_pos-- \
+    	: (CORD__prev(p), 0))
+
+#define CORD_pos_to_index(p) ((p)[0].cur_pos)
+
+#define CORD_pos_to_cord(p) ((p)[0].path[0].pe_cord)
+
+#define CORD_pos_valid(p) ((p)[0].path_len != CORD_POS_INVALID)
+
+/* Some grubby stuff for performance-critical friends:	*/
+#define CORD_pos_chars_left(p) ((long)((p)[0].cur_end) - (long)((p)[0].cur_pos))
+	/* Number of characters in cache.  <= 0 ==> none	*/
+
+#define CORD_pos_advance(p,n) ((p)[0].cur_pos += (n) - 1, CORD_next(p))
+	/* Advance position by n characters	*/
+	/* 0 < n < CORD_pos_chars_left(p)	*/
+
+#define CORD_pos_cur_char_addr(p) \
+	(p)[0].cur_leaf + ((p)[0].cur_pos - (p)[0].cur_start)
+	/* address of current character in cache.	*/
+
+#endif
diff --git a/gc/include/private/gc_hdrs.h b/gc/include/private/gc_hdrs.h
new file mode 100644
index 0000000..60dc2ad
--- /dev/null
+++ b/gc/include/private/gc_hdrs.h
@@ -0,0 +1,135 @@
+/* 
+ * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
+ * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program
+ * for any purpose,  provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is granted,
+ * provided the above notices are retained, and a notice that the code was
+ * modified is included with the above copyright notice.
+ */
+/* Boehm, July 11, 1995 11:54 am PDT */
+# ifndef GC_HEADERS_H
+# define GC_HEADERS_H
+typedef struct hblkhdr hdr;
+
+# if CPP_WORDSZ != 32 && CPP_WORDSZ < 36
+	--> Get a real machine.
+# endif
+
+/*
+ * The 2 level tree data structure that is used to find block headers.
+ * If there are more than 32 bits in a pointer, the top level is a hash
+ * table.
+ */
+
+# if CPP_WORDSZ > 32
+#   define HASH_TL
+# endif
+
+/* Define appropriate out-degrees for each of the two tree levels	*/
+# ifdef SMALL_CONFIG
+#   define LOG_BOTTOM_SZ 11
+	/* Keep top index size reasonable with smaller blocks. */
+# else
+#   define LOG_BOTTOM_SZ 10
+# endif
+# ifndef HASH_TL
+#   define LOG_TOP_SZ (WORDSZ - LOG_BOTTOM_SZ - LOG_HBLKSIZE)
+# else
+#   define LOG_TOP_SZ 11
+# endif
+# define TOP_SZ (1 << LOG_TOP_SZ)
+# define BOTTOM_SZ (1 << LOG_BOTTOM_SZ)
+
+typedef struct bi {
+    hdr * index[BOTTOM_SZ];
+	/*
+ 	 * The bottom level index contains one of three kinds of values:
+	 * 0 means we're not responsible for this block,
+	 *   or this is a block other than the first one in a free block.
+	 * 1 < (long)X <= MAX_JUMP means the block starts at least
+	 *        X * HBLKSIZE bytes before the current address.
+	 * A valid pointer points to a hdr structure. (The above can't be
+	 * valid pointers due to the GET_MEM return convention.)
+	 */
+    struct bi * asc_link;	/* All indices are linked in	*/
+    				/* ascending order...		*/
+    struct bi * desc_link;	/* ... and in descending order.	*/
+    word key;			/* high order address bits.	*/
+# ifdef HASH_TL
+    struct bi * hash_link;	/* Hash chain link.		*/
+# endif
+} bottom_index;
+
+/* extern bottom_index GC_all_nils; - really part of GC_arrays */
+
+/* extern bottom_index * GC_top_index []; - really part of GC_arrays */
+				/* Each entry points to a bottom_index.	*/
+				/* On a 32 bit machine, it points to 	*/
+				/* the index for a set of high order	*/
+				/* bits equal to the index.  For longer	*/
+				/* addresses, we hash the high order	*/
+				/* bits to compute the index in 	*/
+				/* GC_top_index, and each entry points	*/
+				/* to a hash chain.			*/
+				/* The last entry in each chain is	*/
+				/* GC_all_nils.				*/
+
+
+# define MAX_JUMP (HBLKSIZE - 1)
+
+# define HDR_FROM_BI(bi, p) \
+		((bi)->index[((word)(p) >> LOG_HBLKSIZE) & (BOTTOM_SZ - 1)])
+# ifndef HASH_TL
+#   define BI(p) (GC_top_index \
+		[(word)(p) >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE)])
+#   define HDR_INNER(p) HDR_FROM_BI(BI(p),p)
+#   ifdef SMALL_CONFIG
+#	define HDR(p) GC_find_header((ptr_t)(p))
+#   else
+#	define HDR(p) HDR_INNER(p)
+#   endif
+#   define GET_BI(p, bottom_indx) (bottom_indx) = BI(p)
+#   define GET_HDR(p, hhdr) (hhdr) = HDR(p)
+#   define SET_HDR(p, hhdr) HDR_INNER(p) = (hhdr)
+#   define GET_HDR_ADDR(p, ha) (ha) = &(HDR_INNER(p))
+# else /* hash */
+/*  Hash function for tree top level */
+#   define TL_HASH(hi) ((hi) & (TOP_SZ - 1))
+/*  Set bottom_indx to point to the bottom index for address p */
+#   define GET_BI(p, bottom_indx) \
+	{ \
+	    register word hi = \
+	        (word)(p) >> (LOG_BOTTOM_SZ + LOG_HBLKSIZE); \
+	    register bottom_index * _bi = GC_top_index[TL_HASH(hi)]; \
+	    \
+	    while (_bi -> key != hi && _bi != GC_all_nils) \
+	    	_bi = _bi -> hash_link; \
+	    (bottom_indx) = _bi; \
+	}
+#   define GET_HDR_ADDR(p, ha) \
+	{ \
+	    register bottom_index * bi; \
+	    \
+	    GET_BI(p, bi);	\
+	    (ha) = &(HDR_FROM_BI(bi, p)); \
+	}
+#   define GET_HDR(p, hhdr) { register hdr ** _ha; GET_HDR_ADDR(p, _ha); \
+			      (hhdr) = *_ha; }
+#   define SET_HDR(p, hhdr) { register hdr ** _ha; GET_HDR_ADDR(p, _ha); \
+			      *_ha = (hhdr); }
+#   define HDR(p) GC_find_header((ptr_t)(p))
+# endif
+			    
+/* Is the result a forwarding address to someplace closer to the	*/
+/* beginning of the block or NIL?					*/
+# define IS_FORWARDING_ADDR_OR_NIL(hhdr) ((unsigned long) (hhdr) <= MAX_JUMP)
+
+/* Get an HBLKSIZE aligned address closer to the beginning of the block */
+/* h.  Assumes hhdr == HDR(h) and IS_FORWARDING_ADDR(hhdr).		*/
+# define FORWARDED_ADDR(h, hhdr) ((struct hblk *)(h) - (unsigned long)(hhdr))
+# endif /*  GC_HEADERS_H */
diff --git a/gc/include/private/gc_priv.h b/gc/include/private/gc_priv.h
new file mode 100644
index 0000000..5ce52a7
--- /dev/null
+++ b/gc/include/private/gc_priv.h
@@ -0,0 +1,1748 @@
+/* 
+ * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
+ * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program
+ * for any purpose,  provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is granted,
+ * provided the above notices are retained, and a notice that the code was
+ * modified is included with the above copyright notice.
+ */
+/* Boehm, February 16, 1996 2:30 pm PST */
+ 
+
+# ifndef GC_PRIVATE_H
+# define GC_PRIVATE_H
+
+#if defined(mips) && defined(SYSTYPE_BSD) && defined(sony_news)
+    /* sony RISC NEWS, NEWSOS 4 */
+#   define BSD_TIME
+/*    typedef long ptrdiff_t;   -- necessary on some really old systems	*/
+#endif
+
+#if defined(mips) && defined(SYSTYPE_BSD43)
+    /* MIPS RISCOS 4 */
+#   define BSD_TIME
+#endif
+
+#ifdef BSD_TIME
+#   include <sys/types.h>
+#   include <sys/time.h>
+#   include <sys/resource.h>
+#endif /* BSD_TIME */
+
+# ifndef GC_H
+#   include "gc.h"
+# endif
+
+typedef GC_word word;
+typedef GC_signed_word signed_word;
+
+# ifndef CONFIG_H
+#   include "gcconfig.h"
+# endif
+
+# ifndef HEADERS_H
+#   include "gc_hdrs.h"
+# endif
+
+typedef int GC_bool;
+# define TRUE 1
+# define FALSE 0
+
+typedef char * ptr_t;	/* A generic pointer to which we can add	*/
+			/* byte displacements.				*/
+			/* Preferably identical to caddr_t, if it 	*/
+			/* exists.					*/
+			
+#if defined(__STDC__)
+#   include <stdlib.h>
+#   if !(defined( sony_news ) )
+#       include <stddef.h>
+#   endif
+#   define VOLATILE volatile
+#   define CONST const
+#else
+#   ifdef MSWIN32
+#   	include <stdlib.h>
+#   endif
+#   define VOLATILE
+#   define CONST
+#endif
+
+#if 0 /* was once defined for AMIGA */
+#   define GC_FAR __far
+#else
+#   define GC_FAR
+#endif
+
+/*********************************/
+/*                               */
+/* Definitions for conservative  */
+/* collector                     */
+/*                               */
+/*********************************/
+
+/*********************************/
+/*                               */
+/* Easily changeable parameters  */
+/*                               */
+/*********************************/
+
+#define STUBBORN_ALLOC	/* Define stubborn allocation primitives	*/
+#if defined(SRC_M3) || defined(SMALL_CONFIG)
+# undef STUBBORN_ALLOC
+#endif
+
+
+/* #define ALL_INTERIOR_POINTERS */
+		    /* Forces all pointers into the interior of an 	*/
+		    /* object to be considered valid.  Also causes the	*/
+		    /* sizes of all objects to be inflated by at least 	*/
+		    /* one byte.  This should suffice to guarantee	*/
+		    /* that in the presence of a compiler that does	*/
+		    /* not perform garbage-collector-unsafe		*/
+		    /* optimizations, all portable, strictly ANSI	*/
+		    /* conforming C programs should be safely usable	*/
+		    /* with malloc replaced by GC_malloc and free	*/
+		    /* calls removed.  There are several disadvantages: */
+		    /* 1. There are probably no interesting, portable,	*/
+		    /*    strictly ANSI	conforming C programs.		*/
+		    /* 2. This option makes it hard for the collector	*/
+		    /*    to allocate space that is not ``pointed to''  */
+		    /*    by integers, etc.  Under SunOS 4.X with a 	*/
+		    /*    statically linked libc, we empiricaly		*/
+		    /*    observed that it would be difficult to 	*/
+		    /*	  allocate individual objects larger than 100K.	*/
+		    /* 	  Even if only smaller objects are allocated,	*/
+		    /*    more swap space is likely to be needed.       */
+		    /*    Fortunately, much of this will never be	*/
+		    /*    touched.					*/
+		    /* If you can easily avoid using this option, do.	*/
+		    /* If not, try to keep individual objects small.	*/
+		    
+#define PRINTSTATS  /* Print garbage collection statistics          	*/
+		    /* For less verbose output, undefine in reclaim.c 	*/
+
+#define PRINTTIMES  /* Print the amount of time consumed by each garbage   */
+		    /* collection.                                         */
+
+#define PRINTBLOCKS /* Print object sizes associated with heap blocks,     */
+		    /* whether the objects are atomic or composite, and    */
+		    /* whether or not the block was found to be empty      */
+		    /* during the reclaim phase.  Typically generates       */
+		    /* about one screenful per garbage collection.         */
+#undef PRINTBLOCKS
+
+#ifdef SILENT
+#  ifdef PRINTSTATS
+#    undef PRINTSTATS
+#  endif
+#  ifdef PRINTTIMES
+#    undef PRINTTIMES
+#  endif
+#  ifdef PRINTNBLOCKS
+#    undef PRINTNBLOCKS
+#  endif
+#endif
+
+#if defined(PRINTSTATS) && !defined(GATHERSTATS)
+#   define GATHERSTATS
+#endif
+
+#ifdef FINALIZE_ON_DEMAND
+#   define GC_INVOKE_FINALIZERS()
+#else
+#   define GC_INVOKE_FINALIZERS() (void)GC_invoke_finalizers()
+#endif
+
+#define MERGE_SIZES /* Round up some object sizes, so that fewer distinct */
+		    /* free lists are actually maintained.  This applies  */
+		    /* only to the top level routines in misc.c, not to   */
+		    /* user generated code that calls GC_allocobj and     */
+		    /* GC_allocaobj directly.                             */
+		    /* Slows down average programs slightly.  May however */
+		    /* substantially reduce fragmentation if allocation   */
+		    /* request sizes are widely scattered.                */
+		    /* May save significant amounts of space for obj_map  */
+		    /* entries.						  */
+
+#ifndef OLD_BLOCK_ALLOC
+   /* Macros controlling large block allocation strategy.	*/
+#  define EXACT_FIRST  	/* Make a complete pass through the large object */
+			/* free list before splitting a block		 */
+#  define PRESERVE_LAST /* Do not divide last allocated heap segment	 */
+			/* unless we would otherwise need to expand the	 */
+			/* heap.					 */
+#endif
+
+/* ALIGN_DOUBLE requires MERGE_SIZES at present. */
+# if defined(ALIGN_DOUBLE) && !defined(MERGE_SIZES)
+#   define MERGE_SIZES
+# endif
+
+#if defined(ALL_INTERIOR_POINTERS) && !defined(DONT_ADD_BYTE_AT_END)
+# define ADD_BYTE_AT_END
+#endif
+
+
+# ifndef LARGE_CONFIG
+#   define MINHINCR 16	/* Minimum heap increment, in blocks of HBLKSIZE  */
+			/* Must be multiple of largest page size.	  */
+#   define MAXHINCR 512	/* Maximum heap increment, in blocks              */
+# else
+#   define MINHINCR 64
+#   define MAXHINCR 4096
+# endif
+
+# define TIME_LIMIT 50	   /* We try to keep pause times from exceeding	 */
+			   /* this by much. In milliseconds.		 */
+
+# define BL_LIMIT GC_black_list_spacing
+			   /* If we need a block of N bytes, and we have */
+			   /* a block of N + BL_LIMIT bytes available, 	 */
+			   /* and N > BL_LIMIT,				 */
+			   /* but all possible positions in it are 	 */
+			   /* blacklisted, we just use it anyway (and	 */
+			   /* print a warning, if warnings are enabled). */
+			   /* This risks subsequently leaking the block	 */
+			   /* due to a false reference.  But not using	 */
+			   /* the block risks unreasonable immediate	 */
+			   /* heap growth.				 */
+
+/*********************************/
+/*                               */
+/* Stack saving for debugging	 */
+/*                               */
+/*********************************/
+
+#ifdef SAVE_CALL_CHAIN
+
+/*
+ * Number of frames and arguments to save in objects allocated by
+ * debugging allocator.
+ */
+#   define NFRAMES 6	/* Number of frames to save. Even for		*/
+			/* alignment reasons.				*/
+#   define NARGS 2	/* Mumber of arguments to save for each call.	*/
+
+#   define NEED_CALLINFO
+
+/* Fill in the pc and argument information for up to NFRAMES of my	*/
+/* callers.  Ignore my frame and my callers frame.			*/
+void GC_save_callers (/* struct callinfo info[NFRAMES] */);
+
+void GC_print_callers (/* struct callinfo info[NFRAMES] */);
+
+#else
+
+# ifdef GC_ADD_CALLER
+#   define NFRAMES 1
+#   define NARGS 0
+#   define NEED_CALLINFO
+# endif
+
+#endif
+
+#ifdef NEED_CALLINFO
+    struct callinfo {
+	word ci_pc;
+#	if NARGS > 0
+	    word ci_arg[NARGS];	/* bit-wise complement to avoid retention */
+#	endif
+#	if defined(ALIGN_DOUBLE) && (NFRAMES * (NARGS + 1)) % 2 == 1
+	    /* Likely alignment problem. */
+	    word ci_dummy;
+#	endif
+    };
+#endif
+
+
+/*********************************/
+/*                               */
+/* OS interface routines	 */
+/*                               */
+/*********************************/
+
+#ifdef BSD_TIME
+#   undef CLOCK_TYPE
+#   undef GET_TIME
+#   undef MS_TIME_DIFF
+#   define CLOCK_TYPE struct timeval
+#   define GET_TIME(x) { struct rusage rusage; \
+			 getrusage (RUSAGE_SELF,  &rusage); \
+			 x = rusage.ru_utime; }
+#   define MS_TIME_DIFF(a,b) ((double) (a.tv_sec - b.tv_sec) * 1000.0 \
+                               + (double) (a.tv_usec - b.tv_usec) / 1000.0)
+#else /* !BSD_TIME */
+#   include <time.h>
+#   if !defined(__STDC__) && defined(SPARC) && defined(SUNOS4)
+      clock_t clock();	/* Not in time.h, where it belongs	*/
+#   endif
+#   if defined(FREEBSD) && !defined(CLOCKS_PER_SEC)
+#     include <machine/limits.h>
+#     define CLOCKS_PER_SEC CLK_TCK
+#   endif
+#   if !defined(CLOCKS_PER_SEC)
+#     define CLOCKS_PER_SEC 1000000
+/*
+ * This is technically a bug in the implementation.  ANSI requires that
+ * CLOCKS_PER_SEC be defined.  But at least under SunOS4.1.1, it isn't.
+ * Also note that the combination of ANSI C and POSIX is incredibly gross
+ * here. The type clock_t is used by both clock() and times().  But on
+ * some machines these use different notions of a clock tick,  CLOCKS_PER_SEC
+ * seems to apply only to clock.  Hence we use it here.  On many machines,
+ * including SunOS, clock actually uses units of microseconds (which are
+ * not really clock ticks).
+ */
+#   endif
+#   define CLOCK_TYPE clock_t
+#   define GET_TIME(x) x = clock()
+#   define MS_TIME_DIFF(a,b) ((unsigned long) \
+		(1000.0*(double)((a)-(b))/(double)CLOCKS_PER_SEC))
+#endif /* !BSD_TIME */
+
+/* We use bzero and bcopy internally.  They may not be available.	*/
+# if defined(SPARC) && defined(SUNOS4)
+#   define BCOPY_EXISTS
+# endif
+# if defined(M68K) && defined(AMIGA)
+#   define BCOPY_EXISTS
+# endif
+# if defined(M68K) && defined(NEXT)
+#   define BCOPY_EXISTS
+# endif
+# if defined(VAX)
+#   define BCOPY_EXISTS
+# endif
+# if defined(AMIGA)
+#   include <string.h>
+#   define BCOPY_EXISTS
+# endif
+
+# ifndef BCOPY_EXISTS
+#   include <string.h>
+#   define BCOPY(x,y,n) memcpy(y, x, (size_t)(n))
+#   define BZERO(x,n)  memset(x, 0, (size_t)(n))
+# else
+#   define BCOPY(x,y,n) bcopy((char *)(x),(char *)(y),(int)(n))
+#   define BZERO(x,n) bzero((char *)(x),(int)(n))
+# endif
+
+/* HBLKSIZE aligned allocation.  0 is taken to mean failure 	*/
+/* space is assumed to be cleared.				*/
+/* In the case os USE_MMAP, the argument must also be a 	*/
+/* physical page size.						*/
+/* GET_MEM is currently not assumed to retrieve 0 filled space, */
+/* though we should perhaps take advantage of the case in which */
+/* does.							*/
+# ifdef PCR
+    char * real_malloc();
+#   define GET_MEM(bytes) HBLKPTR(real_malloc((size_t)bytes + GC_page_size) \
+				  + GC_page_size-1)
+# else
+#   ifdef OS2
+      void * os2_alloc(size_t bytes);
+#     define GET_MEM(bytes) HBLKPTR((ptr_t)os2_alloc((size_t)bytes \
+				    + GC_page_size) \
+                                    + GC_page_size-1)
+#   else
+#     if defined(AMIGA) || defined(NEXT) || defined(MACOSX) || defined(DOS4GW)
+#       define GET_MEM(bytes) HBLKPTR((size_t) \
+				      calloc(1, (size_t)bytes + GC_page_size) \
+                                      + GC_page_size-1)
+#     else
+#	ifdef MSWIN32
+          extern ptr_t GC_win32_get_mem();
+#         define GET_MEM(bytes) (struct hblk *)GC_win32_get_mem(bytes)
+#	else
+#	  ifdef MACOS
+#	    if defined(USE_TEMPORARY_MEMORY)
+		extern Ptr GC_MacTemporaryNewPtr(size_t size,
+						 Boolean clearMemory);
+#               define GET_MEM(bytes) HBLKPTR( \
+		    GC_MacTemporaryNewPtr(bytes + GC_page_size, true) \
+		    + GC_page_size-1)
+#	    else
+#         	    define GET_MEM(bytes) HBLKPTR( \
+			NewPtrClear(bytes + GC_page_size) + GC_page_size-1)
+#	    endif
+#	  else
+              extern ptr_t GC_unix_get_mem();
+#             define GET_MEM(bytes) (struct hblk *)GC_unix_get_mem(bytes)
+#	  endif
+#	endif
+#     endif
+#   endif
+# endif
+
+/*
+ * Mutual exclusion between allocator/collector routines.
+ * Needed if there is more than one allocator thread.
+ * FASTLOCK() is assumed to try to acquire the lock in a cheap and
+ * dirty way that is acceptable for a few instructions, e.g. by
+ * inhibiting preemption.  This is assumed to have succeeded only
+ * if a subsequent call to FASTLOCK_SUCCEEDED() returns TRUE.
+ * FASTUNLOCK() is called whether or not FASTLOCK_SUCCEEDED().
+ * If signals cannot be tolerated with the FASTLOCK held, then
+ * FASTLOCK should disable signals.  The code executed under
+ * FASTLOCK is otherwise immune to interruption, provided it is
+ * not restarted.
+ * DCL_LOCK_STATE declares any local variables needed by LOCK and UNLOCK
+ * and/or DISABLE_SIGNALS and ENABLE_SIGNALS and/or FASTLOCK.
+ * (There is currently no equivalent for FASTLOCK.)
+ */  
+# ifdef THREADS
+#  ifdef PCR_OBSOLETE	/* Faster, but broken with multiple lwp's	*/
+#    include  "th/PCR_Th.h"
+#    include  "th/PCR_ThCrSec.h"
+     extern struct PCR_Th_MLRep GC_allocate_ml;
+#    define DCL_LOCK_STATE  PCR_sigset_t GC_old_sig_mask
+#    define LOCK() PCR_Th_ML_Acquire(&GC_allocate_ml) 
+#    define UNLOCK() PCR_Th_ML_Release(&GC_allocate_ml)
+#    define FASTLOCK() PCR_ThCrSec_EnterSys()
+     /* Here we cheat (a lot): */
+#        define FASTLOCK_SUCCEEDED() (*(int *)(&GC_allocate_ml) == 0)
+		/* TRUE if nobody currently holds the lock */
+#    define FASTUNLOCK() PCR_ThCrSec_ExitSys()
+#  endif
+#  ifdef PCR
+#    include <base/PCR_Base.h>
+#    include <th/PCR_Th.h>
+     extern PCR_Th_ML GC_allocate_ml;
+#    define DCL_LOCK_STATE \
+	 PCR_ERes GC_fastLockRes; PCR_sigset_t GC_old_sig_mask
+#    define LOCK() PCR_Th_ML_Acquire(&GC_allocate_ml)
+#    define UNLOCK() PCR_Th_ML_Release(&GC_allocate_ml)
+#    define FASTLOCK() (GC_fastLockRes = PCR_Th_ML_Try(&GC_allocate_ml))
+#    define FASTLOCK_SUCCEEDED() (GC_fastLockRes == PCR_ERes_okay)
+#    define FASTUNLOCK()  {\
+        if( FASTLOCK_SUCCEEDED() ) PCR_Th_ML_Release(&GC_allocate_ml); }
+#  endif
+#  ifdef SRC_M3
+     extern word RT0u__inCritical;
+#    define LOCK() RT0u__inCritical++
+#    define UNLOCK() RT0u__inCritical--
+#  endif
+#  ifdef SOLARIS_THREADS
+#    include <thread.h>
+#    include <signal.h>
+     extern mutex_t GC_allocate_ml;
+#    define LOCK() mutex_lock(&GC_allocate_ml);
+#    define UNLOCK() mutex_unlock(&GC_allocate_ml);
+#  endif
+#  ifdef LINUX_THREADS
+#    include <pthread.h>
+#    ifdef __i386__
+       inline static int GC_test_and_set(volatile unsigned int *addr) {
+	  int oldval;
+	  /* Note: the "xchg" instruction does not need a "lock" prefix */
+	  __asm__ __volatile__("xchgl %0, %1"
+		: "=r"(oldval), "=m"(*(addr))
+		: "0"(1), "m"(*(addr)));
+	  return oldval;
+       }
+#    else
+       -- > Need implementation of GC_test_and_set()
+#    endif
+#    define GC_clear(addr) (*(addr) = 0)
+
+     extern volatile unsigned int GC_allocate_lock;
+	/* This is not a mutex because mutexes that obey the (optional)     */
+	/* POSIX scheduling rules are subject to convoys in high contention */
+	/* applications.  This is basically a spin lock.		    */
+     extern pthread_t GC_lock_holder;
+     extern void GC_lock(void);
+	/* Allocation lock holder.  Only set if acquired by client through */
+	/* GC_call_with_alloc_lock.					   */
+#    define SET_LOCK_HOLDER() GC_lock_holder = pthread_self()
+#    define NO_THREAD (pthread_t)(-1)
+#    define UNSET_LOCK_HOLDER() GC_lock_holder = NO_THREAD
+#    define I_HOLD_LOCK() (pthread_equal(GC_lock_holder, pthread_self()))
+#    ifdef UNDEFINED
+#    	define LOCK() pthread_mutex_lock(&GC_allocate_ml)
+#    	define UNLOCK() pthread_mutex_unlock(&GC_allocate_ml)
+#    else
+#	define LOCK() \
+		{ if (GC_test_and_set(&GC_allocate_lock)) GC_lock(); }
+#	define UNLOCK() \
+		GC_clear(&GC_allocate_lock)
+#    endif
+     extern GC_bool GC_collecting;
+#    define ENTER_GC() \
+		{ \
+		    GC_collecting = 1; \
+		}
+#    define EXIT_GC() GC_collecting = 0;
+#  endif /* LINUX_THREADS */
+#  if defined(IRIX_THREADS) || defined(IRIX_JDK_THREADS)
+#    include <pthread.h>
+#    include <mutex.h>
+
+#    if __mips < 3 || !(defined (_ABIN32) || defined(_ABI64)) \
+	|| !defined(_COMPILER_VERSION) || _COMPILER_VERSION < 700
+#        define GC_test_and_set(addr, v) test_and_set(addr,v)
+#    else
+#	 define GC_test_and_set(addr, v) __test_and_set(addr,v)
+#    endif
+     extern unsigned long GC_allocate_lock;
+	/* This is not a mutex because mutexes that obey the (optional) 	*/
+	/* POSIX scheduling rules are subject to convoys in high contention	*/
+	/* applications.  This is basically a spin lock.			*/
+     extern pthread_t GC_lock_holder;
+     extern void GC_lock(void);
+	/* Allocation lock holder.  Only set if acquired by client through */
+	/* GC_call_with_alloc_lock.					   */
+#    define SET_LOCK_HOLDER() GC_lock_holder = pthread_self()
+#    define NO_THREAD (pthread_t)(-1)
+#    define UNSET_LOCK_HOLDER() GC_lock_holder = NO_THREAD
+#    define I_HOLD_LOCK() (pthread_equal(GC_lock_holder, pthread_self()))
+#    ifdef UNDEFINED
+#    	define LOCK() pthread_mutex_lock(&GC_allocate_ml)
+#    	define UNLOCK() pthread_mutex_unlock(&GC_allocate_ml)
+#    else
+#	define LOCK() { if (GC_test_and_set(&GC_allocate_lock, 1)) GC_lock(); }
+#       if __mips >= 3 && (defined (_ABIN32) || defined(_ABI64)) \
+	   && defined(_COMPILER_VERSION) && _COMPILER_VERSION >= 700
+#	    define UNLOCK() __lock_release(&GC_allocate_lock)
+#	else
+	    /* The function call in the following should prevent the	*/
+	    /* compiler from moving assignments to below the UNLOCK.	*/
+	    /* This is probably not necessary for ucode or gcc 2.8.	*/
+	    /* It may be necessary for Ragnarok and future gcc		*/
+	    /* versions.						*/
+#           define UNLOCK() { GC_noop1(&GC_allocate_lock); \
+			*(volatile unsigned long *)(&GC_allocate_lock) = 0; }
+#	endif
+#    endif
+     extern GC_bool GC_collecting;
+#    define ENTER_GC() \
+		{ \
+		    GC_collecting = 1; \
+		}
+#    define EXIT_GC() GC_collecting = 0;
+#  endif /* IRIX_THREADS || IRIX_JDK_THREADS */
+#  ifdef WIN32_THREADS
+#    include <windows.h>
+     GC_API CRITICAL_SECTION GC_allocate_ml;
+#    define LOCK() EnterCriticalSection(&GC_allocate_ml);
+#    define UNLOCK() LeaveCriticalSection(&GC_allocate_ml);
+#  endif
+#  ifndef SET_LOCK_HOLDER
+#      define SET_LOCK_HOLDER()
+#      define UNSET_LOCK_HOLDER()
+#      define I_HOLD_LOCK() FALSE
+		/* Used on platforms were locks can be reacquired,	*/
+		/* so it doesn't matter if we lie.			*/
+#  endif
+# else
+#    define LOCK()
+#    define UNLOCK()
+# endif
+# ifndef SET_LOCK_HOLDER
+#   define SET_LOCK_HOLDER()
+#   define UNSET_LOCK_HOLDER()
+#   define I_HOLD_LOCK() FALSE
+		/* Used on platforms were locks can be reacquired,	*/
+		/* so it doesn't matter if we lie.			*/
+# endif
+# ifndef ENTER_GC
+#   define ENTER_GC()
+#   define EXIT_GC()
+# endif
+
+# ifndef DCL_LOCK_STATE
+#   define DCL_LOCK_STATE
+# endif
+# ifndef FASTLOCK
+#   define FASTLOCK() LOCK()
+#   define FASTLOCK_SUCCEEDED() TRUE
+#   define FASTUNLOCK() UNLOCK()
+# endif
+
+/* Delay any interrupts or signals that may abort this thread.  Data	*/
+/* structures are in a consistent state outside this pair of calls.	*/
+/* ANSI C allows both to be empty (though the standard isn't very	*/
+/* clear on that point).  Standard malloc implementations are usually	*/
+/* neither interruptable nor thread-safe, and thus correspond to	*/
+/* empty definitions.							*/
+# ifdef PCR
+#   define DISABLE_SIGNALS() \
+		 PCR_Th_SetSigMask(PCR_allSigsBlocked,&GC_old_sig_mask)
+#   define ENABLE_SIGNALS() \
+		PCR_Th_SetSigMask(&GC_old_sig_mask, NIL)
+# else
+#   if defined(SRC_M3) || defined(AMIGA) || defined(SOLARIS_THREADS) \
+	|| defined(MSWIN32) || defined(MACOS) || defined(DJGPP) \
+	|| defined(NO_SIGNALS) || defined(IRIX_THREADS) \
+	|| defined(IRIX_JDK_THREADS) || defined(LINUX_THREADS) 
+			/* Also useful for debugging.		*/
+	/* Should probably use thr_sigsetmask for SOLARIS_THREADS. */
+#     define DISABLE_SIGNALS()
+#     define ENABLE_SIGNALS()
+#   else
+#     define DISABLE_SIGNALS() GC_disable_signals()
+	void GC_disable_signals();
+#     define ENABLE_SIGNALS() GC_enable_signals()
+	void GC_enable_signals();
+#   endif
+# endif
+
+/*
+ * Stop and restart mutator threads.
+ */
+# ifdef PCR
+#     include "th/PCR_ThCtl.h"
+#     define STOP_WORLD() \
+ 	PCR_ThCtl_SetExclusiveMode(PCR_ThCtl_ExclusiveMode_stopNormal, \
+ 				   PCR_allSigsBlocked, \
+ 				   PCR_waitForever)
+#     define START_WORLD() \
+	PCR_ThCtl_SetExclusiveMode(PCR_ThCtl_ExclusiveMode_null, \
+ 				   PCR_allSigsBlocked, \
+ 				   PCR_waitForever);
+# else
+#   if defined(SOLARIS_THREADS) || defined(WIN32_THREADS) \
+	|| defined(IRIX_THREADS) || defined(LINUX_THREADS) \
+	|| defined(IRIX_JDK_THREADS)
+      void GC_stop_world();
+      void GC_start_world();
+#     define STOP_WORLD() GC_stop_world()
+#     define START_WORLD() GC_start_world()
+#   else
+#     define STOP_WORLD()
+#     define START_WORLD()
+#   endif
+# endif
+
+/* Abandon ship */
+# ifdef PCR
+#   define ABORT(s) PCR_Base_Panic(s)
+# else
+#   ifdef SMALL_CONFIG
+#	define ABORT(msg) abort();
+#   else
+	GC_API void GC_abort();
+#       define ABORT(msg) GC_abort(msg);
+#   endif
+# endif
+
+/* Exit abnormally, but without making a mess (e.g. out of memory) */
+# ifdef PCR
+#   define EXIT() PCR_Base_Exit(1,PCR_waitForever)
+# else
+#   define EXIT() (void)exit(1)
+# endif
+
+/* Print warning message, e.g. almost out of memory.	*/
+# define WARN(msg,arg) (*GC_current_warn_proc)(msg, (GC_word)(arg))
+extern GC_warn_proc GC_current_warn_proc;
+
+/*********************************/
+/*                               */
+/* Word-size-dependent defines   */
+/*                               */
+/*********************************/
+
+#if CPP_WORDSZ == 32
+#  define WORDS_TO_BYTES(x)   ((x)<<2)
+#  define BYTES_TO_WORDS(x)   ((x)>>2)
+#  define LOGWL               ((word)5)    /* log[2] of CPP_WORDSZ */
+#  define modWORDSZ(n) ((n) & 0x1f)        /* n mod size of word	    */
+#  if ALIGNMENT != 4
+#	define UNALIGNED
+#  endif
+#endif
+
+#if CPP_WORDSZ == 64
+#  define WORDS_TO_BYTES(x)   ((x)<<3)
+#  define BYTES_TO_WORDS(x)   ((x)>>3)
+#  define LOGWL               ((word)6)    /* log[2] of CPP_WORDSZ */
+#  define modWORDSZ(n) ((n) & 0x3f)        /* n mod size of word	    */
+#  if ALIGNMENT != 8
+#	define UNALIGNED
+#  endif
+#endif
+
+#define WORDSZ ((word)CPP_WORDSZ)
+#define SIGNB  ((word)1 << (WORDSZ-1))
+#define BYTES_PER_WORD      ((word)(sizeof (word)))
+#define ONES                ((word)(-1))
+#define divWORDSZ(n) ((n) >> LOGWL)	   /* divide n by size of word      */
+
+/*********************/
+/*                   */
+/*  Size Parameters  */
+/*                   */
+/*********************/
+
+/*  heap block size, bytes. Should be power of 2 */
+
+#ifndef HBLKSIZE
+# ifdef SMALL_CONFIG
+#   define CPP_LOG_HBLKSIZE 10
+# else
+#   if CPP_WORDSZ == 32
+#     define CPP_LOG_HBLKSIZE 12
+#   else
+#     define CPP_LOG_HBLKSIZE 13
+#   endif
+# endif
+#else
+# if HBLKSIZE == 512
+#   define CPP_LOG_HBLKSIZE 9
+# endif
+# if HBLKSIZE == 1024
+#   define CPP_LOG_HBLKSIZE 10
+# endif
+# if HBLKSIZE == 2048
+#   define CPP_LOG_HBLKSIZE 11
+# endif
+# if HBLKSIZE == 4096
+#   define CPP_LOG_HBLKSIZE 12
+# endif
+# if HBLKSIZE == 8192
+#   define CPP_LOG_HBLKSIZE 13
+# endif
+# if HBLKSIZE == 16384
+#   define CPP_LOG_HBLKSIZE 14
+# endif
+# ifndef CPP_LOG_HBLKSIZE
+    --> fix HBLKSIZE
+# endif
+# undef HBLKSIZE
+#endif
+# define CPP_HBLKSIZE (1 << CPP_LOG_HBLKSIZE)
+# define LOG_HBLKSIZE   ((word)CPP_LOG_HBLKSIZE)
+# define HBLKSIZE ((word)CPP_HBLKSIZE)
+
+
+/*  max size objects supported by freelist (larger objects may be   */
+/*  allocated, but less efficiently)                                */
+
+#define CPP_MAXOBJSZ    BYTES_TO_WORDS(CPP_HBLKSIZE/2)
+#define MAXOBJSZ ((word)CPP_MAXOBJSZ)
+		
+# define divHBLKSZ(n) ((n) >> LOG_HBLKSIZE)
+
+# define HBLK_PTR_DIFF(p,q) divHBLKSZ((ptr_t)p - (ptr_t)q)
+	/* Equivalent to subtracting 2 hblk pointers.	*/
+	/* We do it this way because a compiler should	*/
+	/* find it hard to use an integer division	*/
+	/* instead of a shift.  The bundled SunOS 4.1	*/
+	/* o.w. sometimes pessimizes the subtraction to	*/
+	/* involve a call to .div.			*/
+ 
+# define modHBLKSZ(n) ((n) & (HBLKSIZE-1))
+ 
+# define HBLKPTR(objptr) ((struct hblk *)(((word) (objptr)) & ~(HBLKSIZE-1)))
+
+# define HBLKDISPL(objptr) (((word) (objptr)) & (HBLKSIZE-1))
+
+/* Round up byte allocation requests to integral number of words, etc. */
+# ifdef ADD_BYTE_AT_END
+#   define ROUNDED_UP_WORDS(n) BYTES_TO_WORDS((n) + WORDS_TO_BYTES(1))
+#   ifdef ALIGN_DOUBLE
+#       define ALIGNED_WORDS(n) (BYTES_TO_WORDS((n) + WORDS_TO_BYTES(2)) & ~1)
+#   else
+#       define ALIGNED_WORDS(n) ROUNDED_UP_WORDS(n)
+#   endif
+#   define SMALL_OBJ(bytes) ((bytes) < WORDS_TO_BYTES(MAXOBJSZ))
+#   define ADD_SLOP(bytes) ((bytes)+1)
+# else
+#   define ROUNDED_UP_WORDS(n) BYTES_TO_WORDS((n) + (WORDS_TO_BYTES(1) - 1))
+#   ifdef ALIGN_DOUBLE
+#       define ALIGNED_WORDS(n) \
+			(BYTES_TO_WORDS((n) + WORDS_TO_BYTES(2) - 1) & ~1)
+#   else
+#       define ALIGNED_WORDS(n) ROUNDED_UP_WORDS(n)
+#   endif
+#   define SMALL_OBJ(bytes) ((bytes) <= WORDS_TO_BYTES(MAXOBJSZ))
+#   define ADD_SLOP(bytes) (bytes)
+# endif
+
+
+/*
+ * Hash table representation of sets of pages.  This assumes it is
+ * OK to add spurious entries to sets.
+ * Used by black-listing code, and perhaps by dirty bit maintenance code.
+ */
+ 
+# ifdef LARGE_CONFIG
+#   define LOG_PHT_ENTRIES  17
+# else
+#   define LOG_PHT_ENTRIES  14	/* Collisions are likely if heap grows	*/
+				/* to more than 16K hblks = 64MB.	*/
+				/* Each hash table occupies 2K bytes.   */
+# endif
+# define PHT_ENTRIES ((word)1 << LOG_PHT_ENTRIES)
+# define PHT_SIZE (PHT_ENTRIES >> LOGWL)
+typedef word page_hash_table[PHT_SIZE];
+
+# define PHT_HASH(addr) ((((word)(addr)) >> LOG_HBLKSIZE) & (PHT_ENTRIES - 1))
+
+# define get_pht_entry_from_index(bl, index) \
+		(((bl)[divWORDSZ(index)] >> modWORDSZ(index)) & 1)
+# define set_pht_entry_from_index(bl, index) \
+		(bl)[divWORDSZ(index)] |= (word)1 << modWORDSZ(index)
+# define clear_pht_entry_from_index(bl, index) \
+		(bl)[divWORDSZ(index)] &= ~((word)1 << modWORDSZ(index))
+	
+
+
+/********************************************/
+/*                                          */
+/*    H e a p   B l o c k s                 */
+/*                                          */
+/********************************************/
+
+/*  heap block header */
+#define HBLKMASK   (HBLKSIZE-1)
+
+#define BITS_PER_HBLK (HBLKSIZE * 8)
+
+#define MARK_BITS_PER_HBLK (BITS_PER_HBLK/CPP_WORDSZ)
+	   /* upper bound                                    */
+	   /* We allocate 1 bit/word.  Only the first word   */
+	   /* in each object is actually marked.             */
+
+# ifdef ALIGN_DOUBLE
+#   define MARK_BITS_SZ (((MARK_BITS_PER_HBLK + 2*CPP_WORDSZ - 1) \
+			  / (2*CPP_WORDSZ))*2)
+# else
+#   define MARK_BITS_SZ ((MARK_BITS_PER_HBLK + CPP_WORDSZ - 1)/CPP_WORDSZ)
+# endif
+	   /* Upper bound on number of mark words per heap block  */
+
+struct hblkhdr {
+    word hb_sz;  /* If in use, size in words, of objects in the block. */
+		 /* if free, the size in bytes of the whole block      */
+    struct hblk * hb_next; 	/* Link field for hblk free list	 */
+    				/* and for lists of chunks waiting to be */
+    				/* reclaimed.				 */
+    struct hblk * hb_prev;	/* Backwards link for free list.	*/
+    word hb_descr;   		/* object descriptor for marking.  See	*/
+    				/* mark.h.				*/
+    char* hb_map;	/* A pointer to a pointer validity map of the block. */
+    		      	/* See GC_obj_map.				     */
+    		     	/* Valid for all blocks with headers.		     */
+    		     	/* Free blocks point to GC_invalid_map.		     */
+    unsigned char hb_obj_kind;
+    			 /* Kind of objects in the block.  Each kind 	*/
+    			 /* identifies a mark procedure and a set of 	*/
+    			 /* list headers.  Sometimes called regions.	*/
+    unsigned char hb_flags;
+#	define IGNORE_OFF_PAGE	1	/* Ignore pointers that do not	*/
+					/* point to the first page of 	*/
+					/* this object.			*/
+#	define WAS_UNMAPPED 2	/* This is a free block, which has	*/
+				/* been unmapped from the address 	*/
+				/* space.				*/
+				/* GC_remap must be invoked on it	*/
+				/* before it can be reallocated.	*/
+				/* Only set with USE_MUNMAP.		*/
+    unsigned short hb_last_reclaimed;
+    				/* Value of GC_gc_no when block was	*/
+    				/* last allocated or swept. May wrap.   */
+				/* For a free block, this is maintained */
+				/* unly for USE_MUNMAP, and indicates	*/
+				/* when the header was allocated, or	*/
+				/* when the size of the block last	*/
+				/* changed.				*/
+    word hb_marks[MARK_BITS_SZ];
+			    /* Bit i in the array refers to the             */
+			    /* object starting at the ith word (header      */
+			    /* INCLUDED) in the heap block.                 */
+			    /* The lsb of word 0 is numbered 0.		    */
+};
+
+/*  heap block body */
+
+# define DISCARD_WORDS 0
+	/* Number of words to be dropped at the beginning of each block	*/
+	/* Must be a multiple of WORDSZ.  May reasonably be nonzero	*/
+	/* on machines that don't guarantee longword alignment of	*/
+	/* pointers, so that the number of false hits is minimized.	*/
+	/* 0 and WORDSZ are probably the only reasonable values.	*/
+
+# define BODY_SZ ((HBLKSIZE-WORDS_TO_BYTES(DISCARD_WORDS))/sizeof(word))
+
+struct hblk {
+#   if (DISCARD_WORDS != 0)
+        word garbage[DISCARD_WORDS];
+#   endif
+    word hb_body[BODY_SZ];
+};
+
+# define HDR_WORDS ((word)DISCARD_WORDS)
+# define HDR_BYTES ((word)WORDS_TO_BYTES(DISCARD_WORDS))
+
+# define OBJ_SZ_TO_BLOCKS(sz) \
+    divHBLKSZ(HDR_BYTES + WORDS_TO_BYTES(sz) + HBLKSIZE-1)
+    /* Size of block (in units of HBLKSIZE) needed to hold objects of	*/
+    /* given sz (in words).						*/
+
+/* Object free list link */
+# define obj_link(p) (*(ptr_t *)(p))
+
+/* The type of mark procedures.  This really belongs in gc_mark.h.	*/
+/* But we put it here, so that we can avoid scanning the mark proc	*/
+/* table.								*/
+typedef struct ms_entry * (*mark_proc)(/* word * addr, mark_stack_ptr,
+					  mark_stack_limit, env */);
+# define LOG_MAX_MARK_PROCS 6
+# define MAX_MARK_PROCS (1 << LOG_MAX_MARK_PROCS)
+
+/* Root sets.  Logically private to mark_rts.c.  But we don't want the	*/
+/* tables scanned, so we put them here.					*/
+/* MAX_ROOT_SETS is the maximum number of ranges that can be 	*/
+/* registered as static roots. 					*/
+# ifdef LARGE_CONFIG
+#   define MAX_ROOT_SETS 4096
+# else
+#   ifdef PCR
+#     define MAX_ROOT_SETS 1024
+#   else
+#     ifdef MSWIN32
+#	define MAX_ROOT_SETS 512
+	    /* Under NT, we add only written pages, which can result 	*/
+	    /* in many small root sets.					*/
+#     else
+#       define MAX_ROOT_SETS 64
+#     endif
+#   endif
+# endif
+
+# define MAX_EXCLUSIONS (MAX_ROOT_SETS/4)
+/* Maximum number of segments that can be excluded from root sets.	*/
+
+/*
+ * Data structure for excluded static roots.
+ */
+struct exclusion {
+    ptr_t e_start;
+    ptr_t e_end;
+};
+
+/* Data structure for list of root sets.				*/
+/* We keep a hash table, so that we can filter out duplicate additions.	*/
+/* Under Win32, we need to do a better job of filtering overlaps, so	*/
+/* we resort to sequential search, and pay the price.			*/
+struct roots {
+	ptr_t r_start;
+	ptr_t r_end;
+#	ifndef MSWIN32
+	  struct roots * r_next;
+#	endif
+	GC_bool r_tmp;
+	  	/* Delete before registering new dynamic libraries */
+};
+
+#ifndef MSWIN32
+    /* Size of hash table index to roots.	*/
+#   define LOG_RT_SIZE 6
+#   define RT_SIZE (1 << LOG_RT_SIZE) /* Power of 2, may be != MAX_ROOT_SETS */
+#endif
+
+/* Lists of all heap blocks and free lists	*/
+/* as well as other random data structures	*/
+/* that should not be scanned by the		*/
+/* collector.					*/
+/* These are grouped together in a struct	*/
+/* so that they can be easily skipped by the	*/
+/* GC_mark routine.				*/
+/* The ordering is weird to make GC_malloc	*/
+/* faster by keeping the important fields	*/
+/* sufficiently close together that a		*/
+/* single load of a base register will do.	*/
+/* Scalars that could easily appear to		*/
+/* be pointers are also put here.		*/
+/* The main fields should precede any 		*/
+/* conditionally included fields, so that	*/
+/* gc_inl.h will work even if a different set	*/
+/* of macros is defined when the client is	*/
+/* compiled.					*/
+
+struct _GC_arrays {
+  word _heapsize;
+  word _max_heapsize;
+  ptr_t _last_heap_addr;
+  ptr_t _prev_heap_addr;
+  word _large_free_bytes;
+	/* Total bytes contained in blocks on large object free */
+	/* list.						*/
+  word _words_allocd_before_gc;
+		/* Number of words allocated before this	*/
+		/* collection cycle.				*/
+  word _words_allocd;
+  	/* Number of words allocated during this collection cycle */
+  word _words_wasted;
+  	/* Number of words wasted due to internal fragmentation	*/
+  	/* in large objects, or due to dropping blacklisted     */
+	/* blocks, since last gc.  Approximate.                 */
+  word _words_finalized;
+  	/* Approximate number of words in objects (and headers)	*/
+  	/* That became ready for finalization in the last 	*/
+  	/* collection.						*/
+  word _non_gc_bytes_at_gc;
+  	/* Number of explicitly managed bytes of storage 	*/
+  	/* at last collection.					*/
+  word _mem_freed;
+  	/* Number of explicitly deallocated words of memory	*/
+  	/* since last collection.				*/
+  mark_proc _mark_procs[MAX_MARK_PROCS];
+  	/* Table of user-defined mark procedures.  There is	*/
+	/* a small number of these, which can be referenced	*/
+	/* by DS_PROC mark descriptors.  See gc_mark.h.		*/
+  ptr_t _objfreelist[MAXOBJSZ+1];
+			  /* free list for objects */
+  ptr_t _aobjfreelist[MAXOBJSZ+1];
+			  /* free list for atomic objs 	*/
+
+  ptr_t _uobjfreelist[MAXOBJSZ+1];
+			  /* uncollectable but traced objs 	*/
+			  /* objects on this and auobjfreelist  */
+			  /* are always marked, except during   */
+			  /* garbage collections.		*/
+# ifdef ATOMIC_UNCOLLECTABLE
+    ptr_t _auobjfreelist[MAXOBJSZ+1];
+# endif
+			  /* uncollectable but traced objs 	*/
+
+# ifdef GATHERSTATS
+    word _composite_in_use;
+   		/* Number of words in accessible composite	*/
+		/* objects.					*/
+    word _atomic_in_use;
+   		/* Number of words in accessible atomic		*/
+		/* objects.					*/
+# endif
+# ifdef USE_MUNMAP
+    word _unmapped_bytes;
+# endif
+# ifdef MERGE_SIZES
+    unsigned _size_map[WORDS_TO_BYTES(MAXOBJSZ+1)];
+    	/* Number of words to allocate for a given allocation request in */
+    	/* bytes.							 */
+# endif 
+
+# ifdef STUBBORN_ALLOC
+    ptr_t _sobjfreelist[MAXOBJSZ+1];
+# endif
+  			  /* free list for immutable objects	*/
+  ptr_t _obj_map[MAXOBJSZ+1];
+                       /* If not NIL, then a pointer to a map of valid  */
+    		       /* object addresses. _obj_map[sz][i] is j if the	*/
+    		       /* address block_start+i is a valid pointer      */
+    		       /* to an object at				*/
+    		       /* block_start+i&~3 - WORDS_TO_BYTES(j).		*/
+    		       /* (If ALL_INTERIOR_POINTERS is defined, then	*/
+    		       /* instead ((short *)(hb_map[sz])[i] is j if	*/
+    		       /* block_start+WORDS_TO_BYTES(i) is in the	*/
+    		       /* interior of an object starting at		*/
+    		       /* block_start+WORDS_TO_BYTES(i-j)).		*/
+    		       /* It is OBJ_INVALID if				*/
+    		       /* block_start+WORDS_TO_BYTES(i) is not		*/
+    		       /* valid as a pointer to an object.              */
+    		       /* We assume all values of j <= OBJ_INVALID.	*/
+    		       /* The zeroth entry corresponds to large objects.*/
+#   ifdef ALL_INTERIOR_POINTERS
+#	define map_entry_type short
+#       define OBJ_INVALID 0x7fff
+#	define MAP_ENTRY(map, bytes) \
+		(((map_entry_type *)(map))[BYTES_TO_WORDS(bytes)])
+#	define MAP_ENTRIES BYTES_TO_WORDS(HBLKSIZE)
+#	define MAP_SIZE (MAP_ENTRIES * sizeof(map_entry_type))
+#	define OFFSET_VALID(displ) TRUE
+#	define CPP_MAX_OFFSET (HBLKSIZE - HDR_BYTES - 1)
+#	define MAX_OFFSET ((word)CPP_MAX_OFFSET)
+#   else
+#	define map_entry_type char
+#       define OBJ_INVALID 0x7f
+#	define MAP_ENTRY(map, bytes) \
+		(map)[bytes]
+#	define MAP_ENTRIES HBLKSIZE
+#	define MAP_SIZE MAP_ENTRIES
+#	define CPP_MAX_OFFSET (WORDS_TO_BYTES(OBJ_INVALID) - 1)	
+#	define MAX_OFFSET ((word)CPP_MAX_OFFSET)
+# 	define VALID_OFFSET_SZ \
+	  (CPP_MAX_OFFSET > WORDS_TO_BYTES(CPP_MAXOBJSZ)? \
+	   CPP_MAX_OFFSET+1 \
+	   : WORDS_TO_BYTES(CPP_MAXOBJSZ)+1)
+  	char _valid_offsets[VALID_OFFSET_SZ];
+				/* GC_valid_offsets[i] == TRUE ==> i 	*/
+				/* is registered as a displacement.	*/
+#	define OFFSET_VALID(displ) GC_valid_offsets[displ]
+  	char _modws_valid_offsets[sizeof(word)];
+				/* GC_valid_offsets[i] ==>		  */
+				/* GC_modws_valid_offsets[i%sizeof(word)] */
+#   endif
+# ifdef STUBBORN_ALLOC
+    page_hash_table _changed_pages;
+        /* Stubborn object pages that were changes since last call to	*/
+	/* GC_read_changed.						*/
+    page_hash_table _prev_changed_pages;
+        /* Stubborn object pages that were changes before last call to	*/
+	/* GC_read_changed.						*/
+# endif
+# if defined(PROC_VDB) || defined(MPROTECT_VDB)
+    page_hash_table _grungy_pages; /* Pages that were dirty at last 	   */
+				     /* GC_read_dirty.			   */
+# endif
+# ifdef MPROTECT_VDB
+    VOLATILE page_hash_table _dirty_pages;	
+			/* Pages dirtied since last GC_read_dirty. */
+# endif
+# ifdef PROC_VDB
+    page_hash_table _written_pages;	/* Pages ever dirtied	*/
+# endif
+# ifdef LARGE_CONFIG
+#   if CPP_WORDSZ > 32
+#     define MAX_HEAP_SECTS 4096 	/* overflows at roughly 64 GB	   */
+#   else
+#     define MAX_HEAP_SECTS 768		/* Separately added heap sections. */
+#   endif
+# else
+#   define MAX_HEAP_SECTS 256
+# endif
+  struct HeapSect {
+      ptr_t hs_start; word hs_bytes;
+  } _heap_sects[MAX_HEAP_SECTS];
+# ifdef MSWIN32
+    ptr_t _heap_bases[MAX_HEAP_SECTS];
+    		/* Start address of memory regions obtained from kernel. */
+# endif
+  struct roots _static_roots[MAX_ROOT_SETS];
+# ifndef MSWIN32
+    struct roots * _root_index[RT_SIZE];
+# endif
+  struct exclusion _excl_table[MAX_EXCLUSIONS];
+  /* Block header index; see gc_headers.h */
+  bottom_index * _all_nils;
+  bottom_index * _top_index [TOP_SZ];
+#ifdef SAVE_CALL_CHAIN
+  struct callinfo _last_stack[NFRAMES];	/* Stack at last garbage collection.*/
+  					/* Useful for debugging	mysterious  */
+  					/* object disappearances.	    */
+  					/* In the multithreaded case, we    */
+  					/* currently only save the calling  */
+  					/* stack.			    */
+#endif
+};
+
+GC_API GC_FAR struct _GC_arrays GC_arrays; 
+
+# define GC_objfreelist GC_arrays._objfreelist
+# define GC_aobjfreelist GC_arrays._aobjfreelist
+# define GC_uobjfreelist GC_arrays._uobjfreelist
+# ifdef ATOMIC_UNCOLLECTABLE
+#   define GC_auobjfreelist GC_arrays._auobjfreelist
+# endif
+# define GC_sobjfreelist GC_arrays._sobjfreelist
+# define GC_valid_offsets GC_arrays._valid_offsets
+# define GC_modws_valid_offsets GC_arrays._modws_valid_offsets
+# ifdef STUBBORN_ALLOC
+#    define GC_changed_pages GC_arrays._changed_pages
+#    define GC_prev_changed_pages GC_arrays._prev_changed_pages
+# endif
+# define GC_obj_map GC_arrays._obj_map
+# define GC_last_heap_addr GC_arrays._last_heap_addr
+# define GC_prev_heap_addr GC_arrays._prev_heap_addr
+# define GC_words_allocd GC_arrays._words_allocd
+# define GC_words_wasted GC_arrays._words_wasted
+# define GC_large_free_bytes GC_arrays._large_free_bytes
+# define GC_words_finalized GC_arrays._words_finalized
+# define GC_non_gc_bytes_at_gc GC_arrays._non_gc_bytes_at_gc
+# define GC_mem_freed GC_arrays._mem_freed
+# define GC_mark_procs GC_arrays._mark_procs
+# define GC_heapsize GC_arrays._heapsize
+# define GC_max_heapsize GC_arrays._max_heapsize
+# define GC_words_allocd_before_gc GC_arrays._words_allocd_before_gc
+# define GC_heap_sects GC_arrays._heap_sects
+# define GC_last_stack GC_arrays._last_stack
+# ifdef USE_MUNMAP
+#   define GC_unmapped_bytes GC_arrays._unmapped_bytes
+# endif
+# ifdef MSWIN32
+#   define GC_heap_bases GC_arrays._heap_bases
+# endif
+# define GC_static_roots GC_arrays._static_roots
+# define GC_root_index GC_arrays._root_index
+# define GC_excl_table GC_arrays._excl_table
+# define GC_all_nils GC_arrays._all_nils
+# define GC_top_index GC_arrays._top_index
+# if defined(PROC_VDB) || defined(MPROTECT_VDB)
+#   define GC_grungy_pages GC_arrays._grungy_pages
+# endif
+# ifdef MPROTECT_VDB
+#   define GC_dirty_pages GC_arrays._dirty_pages
+# endif
+# ifdef PROC_VDB
+#   define GC_written_pages GC_arrays._written_pages
+# endif
+# ifdef GATHERSTATS
+#   define GC_composite_in_use GC_arrays._composite_in_use
+#   define GC_atomic_in_use GC_arrays._atomic_in_use
+# endif
+# ifdef MERGE_SIZES
+#   define GC_size_map GC_arrays._size_map
+# endif
+
+# define beginGC_arrays ((ptr_t)(&GC_arrays))
+# define endGC_arrays (((ptr_t)(&GC_arrays)) + (sizeof GC_arrays))
+
+/* Object kinds: */
+# define MAXOBJKINDS 16
+
+extern struct obj_kind {
+   ptr_t *ok_freelist;	/* Array of free listheaders for this kind of object */
+   			/* Point either to GC_arrays or to storage allocated */
+   			/* with GC_scratch_alloc.			     */
+   struct hblk **ok_reclaim_list;
+   			/* List headers for lists of blocks waiting to be */
+   			/* swept.					  */
+   word ok_descriptor;  /* Descriptor template for objects in this	*/
+   			/* block.					*/
+   GC_bool ok_relocate_descr;
+   			/* Add object size in bytes to descriptor 	*/
+   			/* template to obtain descriptor.  Otherwise	*/
+   			/* template is used as is.			*/
+   GC_bool ok_init;   /* Clear objects before putting them on the free list. */
+} GC_obj_kinds[MAXOBJKINDS];
+
+# define endGC_obj_kinds (((ptr_t)(&GC_obj_kinds)) + (sizeof GC_obj_kinds))
+
+# define end_gc_area ((ptr_t)endGC_arrays == (ptr_t)(&GC_obj_kinds) ? \
+			endGC_obj_kinds : endGC_arrays)
+
+/* Predefined kinds: */
+# define PTRFREE 0
+# define NORMAL  1
+# define UNCOLLECTABLE 2
+# ifdef ATOMIC_UNCOLLECTABLE
+#   define AUNCOLLECTABLE 3
+#   define STUBBORN 4
+#   define IS_UNCOLLECTABLE(k) (((k) & ~1) == UNCOLLECTABLE)
+# else
+#   define STUBBORN 3
+#   define IS_UNCOLLECTABLE(k) ((k) == UNCOLLECTABLE)
+# endif
+
+extern int GC_n_kinds;
+
+GC_API word GC_fo_entries;
+
+extern word GC_n_heap_sects;	/* Number of separately added heap	*/
+				/* sections.				*/
+
+extern word GC_page_size;
+
+# ifdef MSWIN32
+extern word GC_n_heap_bases;	/* See GC_heap_bases.	*/
+# endif
+
+extern word GC_total_stack_black_listed;
+			/* Number of bytes on stack blacklist. 	*/
+
+extern word GC_black_list_spacing;
+			/* Average number of bytes between blacklisted	*/
+			/* blocks. Approximate.				*/
+			/* Counts only blocks that are 			*/
+			/* "stack-blacklisted", i.e. that are 		*/
+			/* problematic in the interior of an object.	*/
+
+extern char * GC_invalid_map;
+			/* Pointer to the nowhere valid hblk map */
+			/* Blocks pointing to this map are free. */
+
+extern struct hblk * GC_hblkfreelist[];
+				/* List of completely empty heap blocks	*/
+				/* Linked through hb_next field of 	*/
+				/* header structure associated with	*/
+				/* block.				*/
+
+extern GC_bool GC_is_initialized;	/* GC_init() has been run.	*/
+
+extern GC_bool GC_objects_are_marked;	/* There are marked objects in  */
+					/* the heap.			*/
+
+#ifndef SMALL_CONFIG
+  extern GC_bool GC_incremental;
+			/* Using incremental/generational collection. */
+#else
+# define GC_incremental TRUE
+			/* Hopefully allow optimizer to remove some code. */
+#endif
+
+extern GC_bool GC_dirty_maintained;
+				/* Dirty bits are being maintained, 	*/
+				/* either for incremental collection,	*/
+				/* or to limit the root set.		*/
+
+extern word GC_root_size;	/* Total size of registered root sections */
+
+extern GC_bool GC_debugging_started;	/* GC_debug_malloc has been called. */ 
+
+extern ptr_t GC_least_plausible_heap_addr;
+extern ptr_t GC_greatest_plausible_heap_addr;
+			/* Bounds on the heap.  Guaranteed valid	*/
+			/* Likely to include future heap expansion.	*/
+			
+/* Operations */
+# ifndef abs
+#   define abs(x)  ((x) < 0? (-(x)) : (x))
+# endif
+
+
+/*  Marks are in a reserved area in                          */
+/*  each heap block.  Each word has one mark bit associated  */
+/*  with it. Only those corresponding to the beginning of an */
+/*  object are used.                                         */
+
+
+/* Mark bit operations */
+
+/*
+ * Retrieve, set, clear the mark bit corresponding
+ * to the nth word in a given heap block.
+ *
+ * (Recall that bit n corresponds to object beginning at word n
+ * relative to the beginning of the block, including unused words)
+ */
+
+# define mark_bit_from_hdr(hhdr,n) (((hhdr)->hb_marks[divWORDSZ(n)] \
+			    >> (modWORDSZ(n))) & (word)1)
+# define set_mark_bit_from_hdr(hhdr,n) (hhdr)->hb_marks[divWORDSZ(n)] \
+				|= (word)1 << modWORDSZ(n)
+
+# define clear_mark_bit_from_hdr(hhdr,n) (hhdr)->hb_marks[divWORDSZ(n)] \
+				&= ~((word)1 << modWORDSZ(n))
+
+/* Important internal collector routines */
+
+ptr_t GC_approx_sp();
+
+GC_bool GC_should_collect();
+#ifdef PRESERVE_LAST
+    GC_bool GC_in_last_heap_sect(/* ptr_t */);
+	/* In last added heap section?  If so, avoid breaking up.	*/
+#endif
+void GC_apply_to_all_blocks(/*fn, client_data*/);
+			/* Invoke fn(hbp, client_data) for each 	*/
+			/* allocated heap block.			*/
+struct hblk * GC_next_used_block(/* struct hblk * h */);
+			/* Return first in-use block >= h	*/
+struct hblk * GC_prev_block(/* struct hblk * h */);
+			/* Return last block <= h.  Returned block	*/
+			/* is managed by GC, but may or may not be in	*/
+			/* use.						*/
+void GC_mark_init();
+void GC_clear_marks();	/* Clear mark bits for all heap objects. */
+void GC_invalidate_mark_state();	/* Tell the marker that	marked 	   */
+					/* objects may point to	unmarked   */
+					/* ones, and roots may point to	   */
+					/* unmarked objects.		   */
+					/* Reset mark stack.		   */
+void GC_mark_from_mark_stack(); /* Mark from everything on the mark stack. */
+				/* Return after about one pages worth of   */
+				/* work.				   */
+GC_bool GC_mark_stack_empty();
+GC_bool GC_mark_some(/* cold_gc_frame */);
+			/* Perform about one pages worth of marking	*/
+			/* work of whatever kind is needed.  Returns	*/
+			/* quickly if no collection is in progress.	*/
+			/* Return TRUE if mark phase finished.		*/
+void GC_initiate_gc();		/* initiate collection.			*/
+				/* If the mark state is invalid, this	*/
+				/* becomes full colleection.  Otherwise */
+				/* it's partial.			*/
+void GC_push_all(/*b,t*/);	/* Push everything in a range 		*/
+				/* onto mark stack.			*/
+void GC_push_dirty(/*b,t*/);      /* Push all possibly changed	 	*/
+				  /* subintervals of [b,t) onto		*/
+				  /* mark stack.			*/
+#ifndef SMALL_CONFIG
+  void GC_push_conditional(/* ptr_t b, ptr_t t, GC_bool all*/);
+#else
+# define GC_push_conditional(b, t, all) GC_push_all(b, t)
+#endif
+                                /* Do either of the above, depending	*/
+				/* on the third arg.			*/
+void GC_push_all_stack(/*b,t*/);    /* As above, but consider		*/
+				    /*  interior pointers as valid  	*/
+void GC_push_all_eager(/*b,t*/);    /* Same as GC_push_all_stack, but   */
+				    /* ensures that stack is scanned	*/
+				    /* immediately, not just scheduled  */
+				    /* for scanning.			*/
+#ifndef THREADS
+  void GC_push_all_stack_partially_eager(/* bottom, top, cold_gc_frame */);
+			/* Similar to GC_push_all_eager, but only the	*/
+			/* part hotter than cold_gc_frame is scanned	*/
+			/* immediately.  Needed to endure that callee-	*/
+			/* save registers are not missed.		*/
+#else
+  /* In the threads case, we push part of the current thread stack	*/
+  /* with GC_push_all_eager when we push the registers.  This gets the  */
+  /* callee-save registers that may disappear.  The remainder of the	*/
+  /* stacks are scheduled for scanning in *GC_push_other_roots, which	*/
+  /* is thread-package-specific.					*/
+#endif
+void GC_push_current_stack(/* ptr_t cold_gc_frame */);
+			/* Push enough of the current stack eagerly to	*/
+			/* ensure that callee-save registers saved in	*/
+			/* GC frames are scanned.			*/
+			/* In the non-threads case, schedule entire	*/
+			/* stack for scanning.				*/
+void GC_push_roots(/* GC_bool all, ptr_t cold_gc_frame */);
+			/* Push all or dirty roots.	*/
+extern void (*GC_push_other_roots)();
+			/* Push system or application specific roots	*/
+			/* onto the mark stack.  In some environments	*/
+			/* (e.g. threads environments) this is		*/
+			/* predfined to be non-zero.  A client supplied */
+			/* replacement should also call the original	*/
+			/* function.					*/
+extern void (*GC_start_call_back)(/* void */);
+			/* Called at start of full collections.		*/
+			/* Not called if 0.  Called with allocation 	*/
+			/* lock held.					*/
+			/* 0 by default.				*/
+void GC_push_regs();	/* Push register contents onto mark stack.	*/
+void GC_remark();	/* Mark from all marked objects.  Used	*/
+		 	/* only if we had to drop something.	*/
+# if defined(MSWIN32)
+  void __cdecl GC_push_one();
+# else
+  void GC_push_one(/*p*/);    /* If p points to an object, mark it    */
+                              /* and push contents on the mark stack  */
+# endif
+void GC_push_one_checked(/*p*/); /* Ditto, omits plausibility test	*/
+void GC_push_marked(/* struct hblk h, hdr * hhdr */);
+		/* Push contents of all marked objects in h onto	*/
+		/* mark stack.						*/
+#ifdef SMALL_CONFIG
+# define GC_push_next_marked_dirty(h) GC_push_next_marked(h)
+#else
+  struct hblk * GC_push_next_marked_dirty(/* h */);
+		/* Invoke GC_push_marked on next dirty block above h.	*/
+		/* Return a pointer just past the end of this block.	*/
+#endif /* !SMALL_CONFIG */
+struct hblk * GC_push_next_marked(/* h */);
+		/* Ditto, but also mark from clean pages.	*/
+struct hblk * GC_push_next_marked_uncollectable(/* h */);
+		/* Ditto, but mark only from uncollectable pages.	*/
+GC_bool GC_stopped_mark(); /* Stop world and mark from all roots	*/
+			/* and rescuers.			*/
+void GC_clear_hdr_marks(/* hhdr */);  /* Clear the mark bits in a header */
+void GC_set_hdr_marks(/* hhdr */);  /* Set the mark bits in a header */
+void GC_add_roots_inner();
+GC_bool GC_is_static_root(/* ptr_t p */);
+		/* Is the address p in one of the registered static	*/
+		/* root sections?					*/
+void GC_register_dynamic_libraries();
+		/* Add dynamic library data sections to the root set. */
+
+/* Machine dependent startup routines */
+ptr_t GC_get_stack_base();
+void GC_register_data_segments();
+
+/* Black listing: */
+void GC_bl_init(); 	
+# ifndef ALL_INTERIOR_POINTERS
+    void GC_add_to_black_list_normal(/* bits, maybe source */);
+			/* Register bits as a possible future false	*/
+			/* reference from the heap or static data	*/
+#   ifdef PRINT_BLACK_LIST
+#     define GC_ADD_TO_BLACK_LIST_NORMAL(bits, source) \
+			GC_add_to_black_list_normal(bits, source)
+#   else
+#     define GC_ADD_TO_BLACK_LIST_NORMAL(bits, source) \
+			GC_add_to_black_list_normal(bits)
+#   endif
+# else
+#   ifdef PRINT_BLACK_LIST
+#     define GC_ADD_TO_BLACK_LIST_NORMAL(bits, source) \
+			GC_add_to_black_list_stack(bits, source)
+#   else
+#     define GC_ADD_TO_BLACK_LIST_NORMAL(bits, source) \
+			GC_add_to_black_list_stack(bits)
+#   endif
+# endif
+
+void GC_add_to_black_list_stack(/* bits, maybe source */);
+struct hblk * GC_is_black_listed(/* h, len */);
+			/* If there are likely to be false references	*/
+			/* to a block starting at h of the indicated    */
+			/* length, then return the next plausible	*/
+			/* starting location for h that might avoid	*/
+			/* these false references.			*/
+void GC_promote_black_lists();
+			/* Declare an end to a black listing phase.	*/
+void GC_unpromote_black_lists();
+			/* Approximately undo the effect of the above.	*/
+			/* This actually loses some information, but	*/
+			/* only in a reasonably safe way.		*/
+word GC_number_stack_black_listed(/*struct hblk *start, struct hblk *endp1 */);
+			/* Return the number of (stack) blacklisted	*/
+			/* blocks in the range for statistical		*/
+			/* purposes.					*/
+		 	
+ptr_t GC_scratch_alloc(/*bytes*/);
+				/* GC internal memory allocation for	*/
+				/* small objects.  Deallocation is not  */
+				/* possible.				*/
+	
+/* Heap block layout maps: */			
+void GC_invalidate_map(/* hdr */);
+				/* Remove the object map associated	*/
+				/* with the block.  This identifies	*/
+				/* the block as invalid to the mark	*/
+				/* routines.				*/
+GC_bool GC_add_map_entry(/*sz*/);
+				/* Add a heap block map for objects of	*/
+				/* size sz to obj_map.			*/
+				/* Return FALSE on failure.		*/
+void GC_register_displacement_inner(/*offset*/);
+				/* Version of GC_register_displacement	*/
+				/* that assumes lock is already held	*/
+				/* and signals are already disabled.	*/
+
+/*  hblk allocation: */		
+void GC_new_hblk(/*size_in_words, kind*/);
+				/* Allocate a new heap block, and build */
+				/* a free list in it.			*/				
+struct hblk * GC_allochblk(/*size_in_words, kind*/);
+				/* Allocate a heap block, clear it if	*/
+				/* for composite objects, inform	*/
+				/* the marker that block is valid	*/
+				/* for objects of indicated size.	*/
+				/* sz < 0 ==> atomic.			*/ 
+void GC_freehblk();		/* Deallocate a heap block and mark it  */
+				/* as invalid.				*/
+				
+/*  Misc GC: */
+void GC_init_inner();
+GC_bool GC_expand_hp_inner();
+void GC_start_reclaim(/*abort_if_found*/);
+				/* Restore unmarked objects to free	*/
+				/* lists, or (if abort_if_found is	*/
+				/* TRUE) report them.			*/
+				/* Sweeping of small object pages is	*/
+				/* largely deferred.			*/
+void GC_continue_reclaim(/*size, kind*/);
+				/* Sweep pages of the given size and	*/
+				/* kind, as long as possible, and	*/
+				/* as long as the corr. free list is    */
+				/* empty.				*/
+void GC_reclaim_or_delete_all();
+				/* Arrange for all reclaim lists to be	*/
+				/* empty.  Judiciously choose between	*/
+				/* sweeping and discarding each page.	*/
+GC_bool GC_reclaim_all(/* GC_stop_func f*/);
+				/* Reclaim all blocks.  Abort (in a	*/
+				/* consistent state) if f returns TRUE. */
+GC_bool GC_block_empty(/* hhdr */); /* Block completely unmarked? 	*/
+GC_bool GC_never_stop_func();	/* Returns FALSE.		*/
+GC_bool GC_try_to_collect_inner(/* GC_stop_func f */);
+				/* Collect; caller must have acquired	*/
+				/* lock and disabled signals.		*/
+				/* Collection is aborted if f returns	*/
+				/* TRUE.  Returns TRUE if it completes	*/
+				/* successfully.			*/
+# define GC_gcollect_inner() \
+	(void) GC_try_to_collect_inner(GC_never_stop_func)
+void GC_finish_collection();	/* Finish collection.  Mark bits are	*/
+				/* consistent and lock is still held.	*/
+GC_bool GC_collect_or_expand(/* needed_blocks */);
+				/* Collect or expand heap in an attempt */
+				/* make the indicated number of free	*/
+				/* blocks available.  Should be called	*/
+				/* until the blocks are available or	*/
+				/* until it fails by returning FALSE.	*/
+GC_API void GC_init();		/* Initialize collector.		*/
+void GC_collect_a_little_inner(/* int n */);
+				/* Do n units worth of garbage 		*/
+				/* collection work, if appropriate.	*/
+				/* A unit is an amount appropriate for  */
+				/* HBLKSIZE bytes of allocation.	*/
+ptr_t GC_generic_malloc(/* bytes, kind */);
+				/* Allocate an object of the given	*/
+				/* kind.  By default, there are only	*/
+				/* a few kinds: composite(pointerfree), */
+				/* atomic, uncollectable, etc.		*/
+				/* We claim it's possible for clever	*/
+				/* client code that understands GC	*/
+				/* internals to add more, e.g. to	*/
+				/* communicate object layout info	*/
+				/* to the collector.			*/
+ptr_t GC_generic_malloc_ignore_off_page(/* bytes, kind */);
+				/* As above, but pointers past the 	*/
+				/* first page of the resulting object	*/
+				/* are ignored.				*/
+ptr_t GC_generic_malloc_inner(/* bytes, kind */);
+				/* Ditto, but I already hold lock, etc.	*/
+ptr_t GC_generic_malloc_words_small GC_PROTO((size_t words, int kind));
+				/* As above, but size in units of words */
+				/* Bypasses MERGE_SIZES.  Assumes	*/
+				/* words <= MAXOBJSZ.			*/
+ptr_t GC_generic_malloc_inner_ignore_off_page(/* bytes, kind */);
+				/* Allocate an object, where		*/
+				/* the client guarantees that there	*/
+				/* will always be a pointer to the 	*/
+				/* beginning of the object while the	*/
+				/* object is live.			*/
+ptr_t GC_allocobj(/* sz_inn_words, kind */);
+				/* Make the indicated 			*/
+				/* free list nonempty, and return its	*/
+				/* head.				*/
+
+void GC_init_headers();
+GC_bool GC_install_header(/*h*/);
+				/* Install a header for block h.	*/
+				/* Return FALSE on failure.		*/
+GC_bool GC_install_counts(/*h, sz*/);
+				/* Set up forwarding counts for block	*/
+				/* h of size sz.			*/
+				/* Return FALSE on failure.		*/
+void GC_remove_header(/*h*/);
+				/* Remove the header for block h.	*/
+void GC_remove_counts(/*h, sz*/);
+				/* Remove forwarding counts for h.	*/
+hdr * GC_find_header(/*p*/);	/* Debugging only.			*/
+
+void GC_finalize();	/* Perform all indicated finalization actions	*/
+			/* on unmarked objects.				*/
+			/* Unreachable finalizable objects are enqueued	*/
+			/* for processing by GC_invoke_finalizers.	*/
+			/* Invoked with lock.				*/
+			
+void GC_add_to_heap(/*p, bytes*/);
+			/* Add a HBLKSIZE aligned chunk to the heap.	*/
+
+void GC_print_obj(/* ptr_t p */);
+			/* P points to somewhere inside an object with	*/
+			/* debugging info.  Print a human readable	*/
+			/* description of the object to stderr.		*/
+extern void (*GC_check_heap)();
+			/* Check that all objects in the heap with 	*/
+			/* debugging info are intact.  Print 		*/
+			/* descriptions of any that are not.		*/
+extern void (*GC_print_heap_obj)(/* ptr_t p */);
+			/* If possible print s followed by a more	*/
+			/* detailed description of the object 		*/
+			/* referred to by p.				*/
+			
+/* Memory unmapping: */
+#ifdef USE_MUNMAP
+  void GC_unmap_old(void);
+  void GC_merge_unmapped(void);
+  void GC_unmap(ptr_t start, word bytes);
+  void GC_remap(ptr_t start, word bytes);
+  void GC_unmap_gap(ptr_t start1, word bytes1, ptr_t start2, word bytes2);
+#endif
+
+/* Virtual dirty bit implementation:		*/
+/* Each implementation exports the following:	*/
+void GC_read_dirty();	/* Retrieve dirty bits.	*/
+GC_bool GC_page_was_dirty(/* struct hblk * h  */);
+			/* Read retrieved dirty bits.	*/
+GC_bool GC_page_was_ever_dirty(/* struct hblk * h  */);
+			/* Could the page contain valid heap pointers?	*/
+void GC_is_fresh(/* struct hblk * h, word number_of_blocks  */);
+			/* Assert the region currently contains no	*/
+			/* valid pointers.				*/
+void GC_write_hint(/* struct hblk * h  */);
+			/* h is about to be written.	*/
+void GC_dirty_init();
+
+/* Slow/general mark bit manipulation: */
+GC_API GC_bool GC_is_marked();
+void GC_clear_mark_bit();
+void GC_set_mark_bit();
+
+/* Stubborn objects: */
+void GC_read_changed();	/* Analogous to GC_read_dirty */
+GC_bool GC_page_was_changed(/* h */);	/* Analogous to GC_page_was_dirty */
+void GC_clean_changing_list();	/* Collect obsolete changing list entries */
+void GC_stubborn_init();
+
+/* Debugging print routines: */
+void GC_print_block_list();
+void GC_print_hblkfreelist();
+void GC_print_heap_sects();
+void GC_print_static_roots();
+void GC_dump();
+
+#ifdef KEEP_BACK_PTRS
+   void GC_store_back_pointer(ptr_t source, ptr_t dest);
+   void GC_marked_for_finalization(ptr_t dest);
+#  define GC_STORE_BACK_PTR(source, dest) GC_store_back_pointer(source, dest)
+#  define GC_MARKED_FOR_FINALIZATION(dest) GC_marked_for_finalization(dest)
+#else
+#  define GC_STORE_BACK_PTR(source, dest) 
+#  define GC_MARKED_FOR_FINALIZATION(dest)
+#endif
+
+/* Make arguments appear live to compiler */
+# ifdef __WATCOMC__
+  void GC_noop(void*, ...);
+# else
+  GC_API void GC_noop();
+# endif
+
+void GC_noop1(/* word arg */);
+
+/* Logging and diagnostic output: 	*/
+GC_API void GC_printf GC_PROTO((char * format, long, long, long, long, long, long));
+			/* A version of printf that doesn't allocate,	*/
+			/* is restricted to long arguments, and		*/
+			/* (unfortunately) doesn't use varargs for	*/
+			/* portability.  Restricted to 6 args and	*/
+			/* 1K total output length.			*/
+			/* (We use sprintf.  Hopefully that doesn't	*/
+			/* allocate for long arguments.)  		*/
+# define GC_printf0(f) GC_printf(f, 0l, 0l, 0l, 0l, 0l, 0l)
+# define GC_printf1(f,a) GC_printf(f, (long)a, 0l, 0l, 0l, 0l, 0l)
+# define GC_printf2(f,a,b) GC_printf(f, (long)a, (long)b, 0l, 0l, 0l, 0l)
+# define GC_printf3(f,a,b,c) GC_printf(f, (long)a, (long)b, (long)c, 0l, 0l, 0l)
+# define GC_printf4(f,a,b,c,d) GC_printf(f, (long)a, (long)b, (long)c, \
+					    (long)d, 0l, 0l)
+# define GC_printf5(f,a,b,c,d,e) GC_printf(f, (long)a, (long)b, (long)c, \
+					      (long)d, (long)e, 0l)
+# define GC_printf6(f,a,b,c,d,e,g) GC_printf(f, (long)a, (long)b, (long)c, \
+						(long)d, (long)e, (long)g)
+
+void GC_err_printf(/* format, a, b, c, d, e, f */);
+# define GC_err_printf0(f) GC_err_puts(f)
+# define GC_err_printf1(f,a) GC_err_printf(f, (long)a, 0l, 0l, 0l, 0l, 0l)
+# define GC_err_printf2(f,a,b) GC_err_printf(f, (long)a, (long)b, 0l, 0l, 0l, 0l)
+# define GC_err_printf3(f,a,b,c) GC_err_printf(f, (long)a, (long)b, (long)c, \
+						  0l, 0l, 0l)
+# define GC_err_printf4(f,a,b,c,d) GC_err_printf(f, (long)a, (long)b, \
+						    (long)c, (long)d, 0l, 0l)
+# define GC_err_printf5(f,a,b,c,d,e) GC_err_printf(f, (long)a, (long)b, \
+						      (long)c, (long)d, \
+						      (long)e, 0l)
+# define GC_err_printf6(f,a,b,c,d,e,g) GC_err_printf(f, (long)a, (long)b, \
+							(long)c, (long)d, \
+							(long)e, (long)g)
+			/* Ditto, writes to stderr.			*/
+			
+void GC_err_puts(/* char *s */);
+			/* Write s to stderr, don't buffer, don't add	*/
+			/* newlines, don't ...				*/
+
+
+#   ifdef GC_ASSERTIONS
+#	define GC_ASSERT(expr) if(!(expr)) {\
+		GC_err_printf2("Assertion failure: %s:%ld\n", \
+				__FILE__, (unsigned long)__LINE__); \
+		ABORT("assertion failure"); }
+#   else 
+#	define GC_ASSERT(expr)
+#   endif
+
+# endif /* GC_PRIVATE_H */
diff --git a/gc/include/private/gcconfig.h b/gc/include/private/gcconfig.h
new file mode 100644
index 0000000..c9017d3
--- /dev/null
+++ b/gc/include/private/gcconfig.h
@@ -0,0 +1,1099 @@
+/* 
+ * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
+ * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
+ * Copyright (c) 1996 by Silicon Graphics.  All rights reserved.
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program
+ * for any purpose,  provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is granted,
+ * provided the above notices are retained, and a notice that the code was
+ * modified is included with the above copyright notice.
+ */
+ 
+#ifndef CONFIG_H
+
+# define CONFIG_H
+
+/* Machine dependent parameters.  Some tuning parameters can be found	*/
+/* near the top of gc_private.h.					*/
+
+/* Machine specific parts contributed by various people.  See README file. */
+
+/* First a unified test for Linux: */
+# if defined(linux) || defined(__linux__)
+#    define LINUX
+# endif
+
+/* Determine the machine type: */
+# if defined(sun) && defined(mc68000)
+#    define M68K
+#    define SUNOS4
+#    define mach_type_known
+# endif
+# if defined(hp9000s300)
+#    define M68K
+#    define HP
+#    define mach_type_known
+# endif
+# if defined(__OpenBSD__) && defined(m68k)
+#    define M68K
+#    define OPENBSD
+#    define mach_type_known
+# endif
+# if defined(__OpenBSD__) && defined(__sparc__)
+#    define SPARC
+#    define OPENBSD
+#    define mach_type_known
+# endif
+# if defined(__NetBSD__) && defined(m68k)
+#    define M68K
+#    define NETBSD
+#    define mach_type_known
+# endif
+# if defined(vax)
+#    define VAX
+#    ifdef ultrix
+#	define ULTRIX
+#    else
+#	define BSD
+#    endif
+#    define mach_type_known
+# endif
+# if defined(mips) || defined(__mips)
+#    define MIPS
+#    if defined(ultrix) || defined(__ultrix) || defined(__NetBSD__)
+#	define ULTRIX
+#    else
+#	if defined(_SYSTYPE_SVR4) || defined(SYSTYPE_SVR4) || defined(__SYSTYPE_SVR4__)
+#	  define IRIX5   /* or IRIX 6.X */
+#	else
+#	  define RISCOS  /* or IRIX 4.X */
+#	endif
+#    endif
+#    define mach_type_known
+# endif
+# if defined(sequent) && defined(i386)
+#    define I386
+#    define SEQUENT
+#    define mach_type_known
+# endif
+# if defined(sun) && defined(i386)
+#    define I386
+#    define SUNOS5
+#    define mach_type_known
+# endif
+# if (defined(__OS2__) || defined(__EMX__)) && defined(__32BIT__)
+#    define I386
+#    define OS2
+#    define mach_type_known
+# endif
+# if defined(ibm032)
+#   define RT
+#   define mach_type_known
+# endif
+# if defined(sun) && (defined(sparc) || defined(__sparc))
+#   define SPARC
+    /* Test for SunOS 5.x */
+#     include <errno.h>
+#     ifdef ECHRNG
+#       define SUNOS5
+#     else
+#	define SUNOS4
+#     endif
+#   define mach_type_known
+# endif
+# if defined(sparc) && defined(unix) && !defined(sun) && !defined(linux) \
+     && !defined(__OpenBSD__)
+#   define SPARC
+#   define DRSNX
+#   define mach_type_known
+# endif
+# if defined(_IBMR2)
+#   define RS6000
+#   define mach_type_known
+# endif
+# if defined(_M_XENIX) && defined(_M_SYSV) && defined(_M_I386)
+	/* The above test may need refinement	*/
+#   define I386
+#   if defined(_SCO_ELF)
+#     define SCO_ELF
+#   else
+#     define SCO
+#   endif
+#   define mach_type_known
+# endif
+# if defined(_AUX_SOURCE)
+#   define M68K
+#   define SYSV
+#   define mach_type_known
+# endif
+# if defined(_PA_RISC1_0) || defined(_PA_RISC1_1) \
+     || defined(hppa) || defined(__hppa__)
+#   define HP_PA
+#   define mach_type_known
+# endif
+# if defined(LINUX) && (defined(i386) || defined(__i386__))
+#    define I386
+#    define mach_type_known
+# endif
+# if defined(LINUX) && defined(powerpc)
+#    define POWERPC
+#    define mach_type_known
+# endif
+# if defined(LINUX) && defined(__mc68000__)
+#    define M68K
+#    define mach_type_known
+# endif
+# if defined(LINUX) && defined(sparc)
+#    define SPARC
+#    define mach_type_known
+# endif
+# if defined(__alpha) || defined(__alpha__)
+#   define ALPHA
+#   if !defined(LINUX)
+#     define OSF1	/* a.k.a Digital Unix */
+#   endif
+#   define mach_type_known
+# endif
+# if defined(_AMIGA) && !defined(AMIGA)
+#   define AMIGA
+# endif
+# ifdef AMIGA 
+#   define M68K
+#   define mach_type_known
+# endif
+# if defined(THINK_C) || defined(__MWERKS__) && !defined(__powerc)
+#   define M68K
+#   define MACOS
+#   define mach_type_known
+# endif
+# if defined(__MWERKS__) && defined(__powerc)
+#   define POWERPC
+#   define MACOS
+#   define mach_type_known
+# endif
+# if defined(macosx)
+#    define MACOSX
+#    define POWERPC
+#    define mach_type_known
+# endif
+# if defined(NeXT) && defined(mc68000)
+#   define M68K
+#   define NEXT
+#   define mach_type_known
+# endif
+# if defined(NeXT) && defined(i386)
+#   define I386
+#   define NEXT
+#   define mach_type_known
+# endif
+# if defined(__OpenBSD__) && defined(i386)
+#   define I386
+#   define OPENBSD
+#   define mach_type_known
+# endif
+# if defined(__FreeBSD__) && defined(i386)
+#   define I386
+#   define FREEBSD
+#   define mach_type_known
+# endif
+# if defined(__NetBSD__) && defined(i386)
+#   define I386
+#   define NETBSD
+#   define mach_type_known
+# endif
+# if defined(bsdi) && defined(i386)
+#    define I386
+#    define BSDI
+#    define mach_type_known
+# endif
+# if !defined(mach_type_known) && defined(__386BSD__)
+#   define I386
+#   define THREE86BSD
+#   define mach_type_known
+# endif
+# if defined(_CX_UX) && defined(_M88K)
+#   define M88K
+#   define CX_UX
+#   define mach_type_known
+# endif
+# if defined(DGUX)
+#   define M88K
+    /* DGUX defined */
+#   define mach_type_known
+# endif
+# if (defined(_MSDOS) || defined(_MSC_VER)) && (_M_IX86 >= 300) \
+     || defined(_WIN32) && !defined(__CYGWIN32__) && !defined(__CYGWIN__)
+#   define I386
+#   define MSWIN32	/* or Win32s */
+#   define mach_type_known
+# endif
+# if defined(__DJGPP__)
+#   define I386
+#   ifndef DJGPP
+#     define DJGPP  /* MSDOS running the DJGPP port of GCC */
+#   endif
+#   define mach_type_known
+# endif
+# if defined(__CYGWIN32__) || defined(__CYGWIN__)
+#   define I386
+#   define CYGWIN32
+#   define mach_type_known
+# endif
+# if defined(__BORLANDC__)
+#   define I386
+#   define MSWIN32
+#   define mach_type_known
+# endif
+# if defined(_UTS) && !defined(mach_type_known)
+#   define S370
+#   define UTS4
+#   define mach_type_known
+# endif
+/* Ivan Demakov */
+# if defined(__WATCOMC__) && defined(__386__)
+#   define I386
+#   if !defined(OS2) && !defined(MSWIN32) && !defined(DOS4GW)
+#     if defined(__OS2__)
+#       define OS2
+#     else
+#       if defined(__WINDOWS_386__) || defined(__NT__)
+#         define MSWIN32
+#       else
+#         define DOS4GW
+#       endif
+#     endif
+#   endif
+#   define mach_type_known
+# endif
+
+/* Feel free to add more clauses here */
+
+/* Or manually define the machine type here.  A machine type is 	*/
+/* characterized by the architecture.  Some				*/
+/* machine types are further subdivided by OS.				*/
+/* the macros ULTRIX, RISCOS, and BSD to distinguish.			*/
+/* Note that SGI IRIX is treated identically to RISCOS.			*/
+/* SYSV on an M68K actually means A/UX.					*/
+/* The distinction in these cases is usually the stack starting address */
+# ifndef mach_type_known
+	--> unknown machine type
+# endif
+		    /* Mapping is: M68K       ==> Motorola 680X0	*/
+		    /*		   (SUNOS4,HP,NEXT, and SYSV (A/UX),	*/
+		    /*		   MACOS and AMIGA variants)		*/
+		    /*             I386       ==> Intel 386	 	*/
+		    /*		    (SEQUENT, OS2, SCO, LINUX, NETBSD,	*/
+		    /*		     FREEBSD, THREE86BSD, MSWIN32,	*/
+		    /* 		     BSDI,SUNOS5, NEXT, other variants)	*/
+                    /*             NS32K      ==> Encore Multimax 	*/
+                    /*             MIPS       ==> R2000 or R3000	*/
+                    /*			(RISCOS, ULTRIX variants)	*/
+                    /*		   VAX	      ==> DEC VAX		*/
+                    /*			(BSD, ULTRIX variants)		*/
+                    /*		   RS6000     ==> IBM RS/6000 AIX3.X	*/
+                    /*		   RT	      ==> IBM PC/RT		*/
+                    /*		   HP_PA      ==> HP9000/700 & /800	*/
+                    /*				  HP/UX			*/
+		    /*		   SPARC      ==> SPARC under SunOS	*/
+		    /*			(SUNOS4, SUNOS5,		*/
+		    /*			 DRSNX variants)		*/
+		    /* 		   ALPHA      ==> DEC Alpha 		*/
+		    /*			(OSF1 and LINUX variants)	*/
+		    /* 		   M88K       ==> Motorola 88XX0        */
+		    /* 		        (CX_UX and DGUX)		*/
+		    /* 		   S370	      ==> 370-like machine	*/
+		    /* 			running Amdahl UTS4		*/
+
+
+/*
+ * For each architecture and OS, the following need to be defined:
+ *
+ * CPP_WORD_SZ is a simple integer constant representing the word size.
+ * in bits.  We assume byte addressibility, where a byte has 8 bits.
+ * We also assume CPP_WORD_SZ is either 32 or 64.
+ * (We care about the length of pointers, not hardware
+ * bus widths.  Thus a 64 bit processor with a C compiler that uses
+ * 32 bit pointers should use CPP_WORD_SZ of 32, not 64. Default is 32.)
+ *
+ * MACH_TYPE is a string representation of the machine type.
+ * OS_TYPE is analogous for the OS.
+ *
+ * ALIGNMENT is the largest N, such that
+ * all pointer are guaranteed to be aligned on N byte boundaries.
+ * defining it to be 1 will always work, but perform poorly.
+ *
+ * DATASTART is the beginning of the data segment.
+ * On UNIX systems, the collector will scan the area between DATASTART
+ * and DATAEND for root pointers.
+ *
+ * DATAEND, if not &end.
+ *
+ * ALIGN_DOUBLE of GC_malloc should return blocks aligned to twice
+ * the pointer size.
+ *
+ * STACKBOTTOM is the cool end of the stack, which is usually the
+ * highest address in the stack.
+ * Under PCR or OS/2, we have other ways of finding thread stacks.
+ * For each machine, the following should:
+ * 1) define STACK_GROWS_UP if the stack grows toward higher addresses, and
+ * 2) define exactly one of
+ *	STACKBOTTOM (should be defined to be an expression)
+ *	HEURISTIC1
+ *	HEURISTIC2
+ * If either of the last two macros are defined, then STACKBOTTOM is computed
+ * during collector startup using one of the following two heuristics:
+ * HEURISTIC1:  Take an address inside GC_init's frame, and round it up to
+ *		the next multiple of STACK_GRAN.
+ * HEURISTIC2:  Take an address inside GC_init's frame, increment it repeatedly
+ *		in small steps (decrement if STACK_GROWS_UP), and read the value
+ *		at each location.  Remember the value when the first
+ *		Segmentation violation or Bus error is signalled.  Round that
+ *		to the nearest plausible page boundary, and use that instead
+ *		of STACKBOTTOM.
+ *
+ * If no expression for STACKBOTTOM can be found, and neither of the above
+ * heuristics are usable, the collector can still be used with all of the above
+ * undefined, provided one of the following is done:
+ * 1) GC_mark_roots can be changed to somehow mark from the correct stack(s)
+ *    without reference to STACKBOTTOM.  This is appropriate for use in
+ *    conjunction with thread packages, since there will be multiple stacks.
+ *    (Allocating thread stacks in the heap, and treating them as ordinary
+ *    heap data objects is also possible as a last resort.  However, this is
+ *    likely to introduce significant amounts of excess storage retention
+ *    unless the dead parts of the thread stacks are periodically cleared.)
+ * 2) Client code may set GC_stackbottom before calling any GC_ routines.
+ *    If the author of the client code controls the main program, this is
+ *    easily accomplished by introducing a new main program, setting
+ *    GC_stackbottom to the address of a local variable, and then calling
+ *    the original main program.  The new main program would read something
+ *    like:
+ *
+ *		# include "gc_private.h"
+ *
+ *		main(argc, argv, envp)
+ *		int argc;
+ *		char **argv, **envp;
+ *		{
+ *		    int dummy;
+ *
+ *		    GC_stackbottom = (ptr_t)(&dummy);
+ *		    return(real_main(argc, argv, envp));
+ *		}
+ *
+ *
+ * Each architecture may also define the style of virtual dirty bit
+ * implementation to be used:
+ *   MPROTECT_VDB: Write protect the heap and catch faults.
+ *   PROC_VDB: Use the SVR4 /proc primitives to read dirty bits.
+ *
+ * An architecture may define DYNAMIC_LOADING if dynamic_load.c
+ * defined GC_register_dynamic_libraries() for the architecture.
+ */
+
+
+# define STACK_GRAN 0x1000000
+# ifdef M68K
+#   define MACH_TYPE "M68K"
+#   define ALIGNMENT 2
+#   ifdef OPENBSD
+#	define OS_TYPE "OPENBSD"
+#	define HEURISTIC2
+	extern char etext;
+#	define DATASTART ((ptr_t)(&etext))
+#   endif
+#   ifdef NETBSD
+#	define OS_TYPE "NETBSD"
+#	define HEURISTIC2
+	extern char etext;
+#	define DATASTART ((ptr_t)(&etext))
+#   endif
+#   ifdef LINUX
+#       define OS_TYPE "LINUX"
+#       define STACKBOTTOM ((ptr_t)0xf0000000)
+#       define MPROTECT_VDB
+#       ifdef __ELF__
+#            define DYNAMIC_LOADING
+             extern char **__environ;
+#            define DATASTART ((ptr_t)(&__environ))
+                             /* hideous kludge: __environ is the first */
+                             /* word in crt0.o, and delimits the start */
+                             /* of the data segment, no matter which   */
+                             /* ld options were passed through.        */
+                             /* We could use _etext instead, but that  */
+                             /* would include .rodata, which may       */
+                             /* contain large read-only data tables    */
+                             /* that we'd rather not scan.             */
+             extern int _end;
+#            define DATAEND (&_end)
+#       else
+             extern int etext;
+#            define DATASTART ((ptr_t)((((word) (&etext)) + 0xfff) & ~0xfff))
+#       endif
+#   endif
+#   ifdef SUNOS4
+#	define OS_TYPE "SUNOS4"
+	extern char etext;
+#	define DATASTART ((ptr_t)((((word) (&etext)) + 0x1ffff) & ~0x1ffff))
+#	define HEURISTIC1	/* differs	*/
+#	define DYNAMIC_LOADING
+#   endif
+#   ifdef HP
+#	define OS_TYPE "HP"
+	extern char etext;
+#       define DATASTART ((ptr_t)((((word) (&etext)) + 0xfff) & ~0xfff))
+#       define STACKBOTTOM ((ptr_t) 0xffeffffc)
+			      /* empirically determined.  seems to work. */
+#  	include <unistd.h>
+#	define GETPAGESIZE() sysconf(_SC_PAGE_SIZE)
+#   endif
+#   ifdef SYSV
+#	define OS_TYPE "SYSV"
+	extern etext;
+#   	define DATASTART ((ptr_t)((((word) (&etext)) + 0x3fffff) \
+				   & ~0x3fffff) \
+				  +((word)&etext & 0x1fff))
+	/* This only works for shared-text binaries with magic number 0413.
+	   The other sorts of SysV binaries put the data at the end of the text,
+	   in which case the default of &etext would work.  Unfortunately,
+	   handling both would require having the magic-number available.
+	   	   		-- Parag
+	   */
+#	define STACKBOTTOM ((ptr_t)0xFFFFFFFE)
+			/* The stack starts at the top of memory, but   */
+			/* 0x0 cannot be used as setjump_test complains */
+			/* that the stack direction is incorrect.  Two  */
+			/* bytes down from 0x0 should be safe enough.   */
+			/* 		--Parag				*/
+#   	include <sys/mmu.h>
+#	define GETPAGESIZE() PAGESIZE	/* Is this still right? */
+#   endif
+#   ifdef AMIGA
+#	define OS_TYPE "AMIGA"
+ 	    	/* STACKBOTTOM and DATASTART handled specially	*/
+ 	    	/* in os_dep.c					*/
+# 	define DATAEND	/* not needed */
+#	define GETPAGESIZE() 4096
+#   endif
+#   ifdef MACOS
+#     ifndef __LOWMEM__
+#     include <LowMem.h>
+#     endif
+#     define OS_TYPE "MACOS"
+			/* see os_dep.c for details of global data segments. */
+#     define STACKBOTTOM ((ptr_t) LMGetCurStackBase())
+#     define DATAEND	/* not needed */
+#     define GETPAGESIZE() 4096
+#   endif
+#   ifdef NEXT
+#	define OS_TYPE "NEXT"
+#	define DATASTART ((ptr_t) get_etext())
+#	define STACKBOTTOM ((ptr_t) 0x4000000)
+#	define DATAEND	/* not needed */
+#   endif
+# endif
+
+# ifdef POWERPC
+#   define MACH_TYPE "POWERPC"
+#   ifdef MACOS
+#     define ALIGNMENT 2  /* Still necessary?  Could it be 4?	*/
+#     ifndef __LOWMEM__
+#     include <LowMem.h>
+#     endif
+#     define OS_TYPE "MACOS"
+			/* see os_dep.c for details of global data segments. */
+#     define STACKBOTTOM ((ptr_t) LMGetCurStackBase())
+#     define DATAEND  /* not needed */
+#   endif
+#   ifdef LINUX
+#     define ALIGNMENT 4	/* Guess.  Can someone verify?	*/
+				/* This was 2, but that didn't sound right. */
+#     define OS_TYPE "LINUX"
+#     define HEURISTIC1
+#     undef STACK_GRAN
+#     define STACK_GRAN 0x10000000
+	/* Stack usually starts at 0x80000000 */
+#     define DATASTART GC_data_start
+      extern int _end;
+#     define DATAEND (&_end)
+#   endif
+#   ifdef MACOSX
+#     define ALIGNMENT 4
+#     define OS_TYPE "MACOSX"
+#     define DATASTART ((ptr_t) get_etext())
+#     define STACKBOTTOM ((ptr_t) 0xc0000000)
+#     define DATAEND	/* not needed */
+#   endif
+# endif
+
+# ifdef VAX
+#   define MACH_TYPE "VAX"
+#   define ALIGNMENT 4	/* Pointers are longword aligned by 4.2 C compiler */
+    extern char etext;
+#   define DATASTART ((ptr_t)(&etext))
+#   ifdef BSD
+#	define OS_TYPE "BSD"
+#	define HEURISTIC1
+			/* HEURISTIC2 may be OK, but it's hard to test. */
+#   endif
+#   ifdef ULTRIX
+#	define OS_TYPE "ULTRIX"
+#	define STACKBOTTOM ((ptr_t) 0x7fffc800)
+#   endif
+# endif
+
+# ifdef RT
+#   define MACH_TYPE "RT"
+#   define ALIGNMENT 4
+#   define DATASTART ((ptr_t) 0x10000000)
+#   define STACKBOTTOM ((ptr_t) 0x1fffd800)
+# endif
+
+# ifdef SPARC
+#   define MACH_TYPE "SPARC"
+#   define ALIGNMENT 4	/* Required by hardware	*/
+#   define ALIGN_DOUBLE
+    extern int etext;
+#   ifdef SUNOS5
+#	define OS_TYPE "SUNOS5"
+	extern int _etext;
+	extern int _end;
+	extern char * GC_SysVGetDataStart();
+#       define DATASTART (ptr_t)GC_SysVGetDataStart(0x10000, &_etext)
+#	define DATAEND (&_end)
+#	ifndef USE_MMAP
+#	    define USE_MMAP
+#	endif
+#       ifdef USE_MMAP
+#         define HEAP_START (ptr_t)0x40000000
+#       else
+#	  define HEAP_START DATAEND
+#       endif
+#	define PROC_VDB
+/*	HEURISTIC1 reportedly no longer works under 2.7.  Thus we	*/
+/* 	switched to HEURISTIC2, eventhough it creates some debugging	*/
+/*	issues.								*/
+#	define HEURISTIC2
+#	include <unistd.h>
+#       define GETPAGESIZE()  sysconf(_SC_PAGESIZE)
+		/* getpagesize() appeared to be missing from at least one */
+		/* Solaris 5.4 installation.  Weird.			  */
+#	define DYNAMIC_LOADING
+#   endif
+#   ifdef SUNOS4
+#	define OS_TYPE "SUNOS4"
+	/* [If you have a weak stomach, don't read this.]		*/
+	/* We would like to use:					*/
+/* #       define DATASTART ((ptr_t)((((word) (&etext)) + 0x1fff) & ~0x1fff)) */
+	/* This fails occasionally, due to an ancient, but very 	*/
+	/* persistent ld bug.  &etext is set 32 bytes too high.		*/
+	/* We instead read the text segment size from the a.out		*/
+	/* header, which happens to be mapped into our address space	*/
+	/* at the start of the text segment.  The detective work here	*/
+	/* was done by Robert Ehrlich, Manuel Serrano, and Bernard	*/
+	/* Serpette of INRIA.						*/
+	/* This assumes ZMAGIC, i.e. demand-loadable executables.	*/
+#	define TEXTSTART 0x2000
+#       define DATASTART ((ptr_t)(*(int *)(TEXTSTART+0x4)+TEXTSTART))
+#	define MPROTECT_VDB
+#	define HEURISTIC1
+# 	define DYNAMIC_LOADING
+#   endif
+#   ifdef DRSNX
+#       define CPP_WORDSZ 32
+#	define OS_TYPE "DRSNX"
+	extern char * GC_SysVGetDataStart();
+	extern int etext;
+#       define DATASTART (ptr_t)GC_SysVGetDataStart(0x10000, &etext)
+#	define MPROTECT_VDB
+#       define STACKBOTTOM ((ptr_t) 0xdfff0000)
+#	define DYNAMIC_LOADING
+#   endif
+#   ifdef LINUX
+#     define OS_TYPE "LINUX"
+#     ifdef __ELF__
+#         define DATASTART GC_data_start
+#         define DYNAMIC_LOADING
+#     else
+          Linux Sparc non elf ?
+#     endif
+      extern int _end;
+#     define DATAEND (&_end)
+#     define SVR4
+#     define STACKBOTTOM ((ptr_t) 0xf0000000)
+#   endif
+#   ifdef OPENBSD
+#     define OS_TYPE "OPENBSD"
+#     define STACKBOTTOM ((ptr_t) 0xf8000000)
+#     define DATASTART ((ptr_t)(&etext))
+#   endif
+# endif
+
+# ifdef I386
+#   define MACH_TYPE "I386"
+#   define ALIGNMENT 4	/* Appears to hold for all "32 bit" compilers	*/
+			/* except Borland.  The -a4 option fixes 	*/
+			/* Borland.					*/
+                        /* Ivan Demakov: For Watcom the option is -zp4. */
+#   ifndef SMALL_CONFIG
+#     define ALIGN_DOUBLE /* Not strictly necessary, but may give speed   */
+			  /* improvement on Pentiums.			  */
+#   endif
+#   ifdef SEQUENT
+#	define OS_TYPE "SEQUENT"
+	extern int etext;
+#       define DATASTART ((ptr_t)((((word) (&etext)) + 0xfff) & ~0xfff))
+#       define STACKBOTTOM ((ptr_t) 0x3ffff000) 
+#   endif
+#   ifdef SUNOS5
+#	define OS_TYPE "SUNOS5"
+  	extern int etext, _start;
+  	extern char * GC_SysVGetDataStart();
+#       define DATASTART GC_SysVGetDataStart(0x1000, &etext)
+#	define STACKBOTTOM ((ptr_t)(&_start))
+/** At least in Solaris 2.5, PROC_VDB gives wrong values for dirty bits. */
+/*#	define PROC_VDB*/
+#	define DYNAMIC_LOADING
+#	ifndef USE_MMAP
+#	    define USE_MMAP
+#	endif
+#       ifdef USE_MMAP
+#         define HEAP_START (ptr_t)0x40000000
+#       else
+#	  define HEAP_START DATAEND
+#       endif
+#   endif
+#   ifdef SCO
+#	define OS_TYPE "SCO"
+	extern int etext;
+#   	define DATASTART ((ptr_t)((((word) (&etext)) + 0x3fffff) \
+				  & ~0x3fffff) \
+				 +((word)&etext & 0xfff))
+#	define STACKBOTTOM ((ptr_t) 0x7ffffffc)
+#   endif
+#   ifdef SCO_ELF
+#       define OS_TYPE "SCO_ELF"
+        extern int etext;
+#       define DATASTART ((ptr_t)(&etext))
+#       define STACKBOTTOM ((ptr_t) 0x08048000)
+#       define DYNAMIC_LOADING
+#	define ELF_CLASS ELFCLASS32
+#   endif
+#   ifdef LINUX
+#	define OS_TYPE "LINUX"
+#       define HEURISTIC1
+#       undef STACK_GRAN
+#       define STACK_GRAN 0x10000000
+	/* STACKBOTTOM is usually 0xc0000000, but this changes with	*/
+	/* different kernel configurations.  In particular, systems	*/
+	/* with 2GB physical memory will usually move the user		*/
+	/* address space limit, and hence initial SP to 0x80000000.	*/
+#       if !defined(LINUX_THREADS) || !defined(REDIRECT_MALLOC)
+#	    define MPROTECT_VDB
+#	else
+	    /* We seem to get random errors in incremental mode,	*/
+	    /* possibly because Linux threads is itself a malloc client */
+	    /* and can't deal with the signals.				*/
+#	endif
+#       ifdef __ELF__
+#            define DYNAMIC_LOADING
+#	     ifdef UNDEFINED	/* includes ro data */
+	       extern int _etext;
+#              define DATASTART ((ptr_t)((((word) (&_etext)) + 0xfff) & ~0xfff))
+#	     endif
+#	     include <features.h>
+#	     if defined(__GLIBC__) && __GLIBC__ >= 2
+		 extern int __data_start;
+#		 define DATASTART ((ptr_t)(&__data_start))
+#	     else
+     	         extern char **__environ;
+#                define DATASTART ((ptr_t)(&__environ))
+			      /* hideous kludge: __environ is the first */
+			      /* word in crt0.o, and delimits the start */
+			      /* of the data segment, no matter which   */
+			      /* ld options were passed through.        */
+			      /* We could use _etext instead, but that  */
+			      /* would include .rodata, which may       */
+			      /* contain large read-only data tables    */
+			      /* that we'd rather not scan.		*/
+#	     endif
+	     extern int _end;
+#	     define DATAEND (&_end)
+#	else
+	     extern int etext;
+#            define DATASTART ((ptr_t)((((word) (&etext)) + 0xfff) & ~0xfff))
+#       endif
+#   endif
+#   ifdef CYGWIN32
+#       define OS_TYPE "CYGWIN32"
+          extern int _data_start__;
+          extern int _data_end__;
+          extern int _bss_start__;
+          extern int _bss_end__;
+  	/* For binutils 2.9.1, we have			*/
+  	/*	DATASTART   = _data_start__		*/
+  	/*	DATAEND	    = _bss_end__		*/
+  	/* whereas for some earlier versions it was	*/
+  	/*	DATASTART   = _bss_start__		*/
+  	/*	DATAEND	    = _data_end__		*/
+  	/* To get it right for both, we take the	*/
+  	/* minumum/maximum of the two.			*/
+#   	define MAX(x,y) ((x) > (y) ? (x) : (y))
+#   	define MIN(x,y) ((x) < (y) ? (x) : (y))
+#       define DATASTART ((ptr_t) MIN(&_data_start__, &_bss_start__))
+#       define DATAEND	 ((ptr_t) MAX(&_data_end__, &_bss_end__))
+#	undef STACK_GRAN
+#       define STACK_GRAN 0x10000
+#       define HEURISTIC1
+#   endif
+#   ifdef OS2
+#	define OS_TYPE "OS2"
+ 	    	/* STACKBOTTOM and DATASTART are handled specially in 	*/
+		/* os_dep.c. OS2 actually has the right			*/
+		/* system call!						*/
+#	define DATAEND	/* not needed */
+#   endif
+#   ifdef MSWIN32
+#	define OS_TYPE "MSWIN32"
+		/* STACKBOTTOM and DATASTART are handled specially in 	*/
+		/* os_dep.c.						*/
+#       ifndef __WATCOMC__
+#	  define MPROTECT_VDB
+#	endif
+#       define DATAEND  /* not needed */
+#   endif
+#   ifdef DJGPP
+#       define OS_TYPE "DJGPP"
+#       include "stubinfo.h"
+        extern int etext;
+        extern int _stklen;
+        extern int __djgpp_stack_limit;
+#       define DATASTART ((ptr_t)((((word) (&etext)) + 0x1ff) & ~0x1ff))
+/* #       define STACKBOTTOM ((ptr_t)((word) _stubinfo + _stubinfo->size \
+                                                     + _stklen)) */
+#       define STACKBOTTOM ((ptr_t)((word) __djgpp_stack_limit + _stklen))
+		/* This may not be right.  */
+#   endif
+#   ifdef OPENBSD
+#	define OS_TYPE "OPENBSD"
+#   endif
+#   ifdef FREEBSD
+#	define OS_TYPE "FREEBSD"
+#	define MPROTECT_VDB
+#   endif
+#   ifdef NETBSD
+#	define OS_TYPE "NETBSD"
+#   endif
+#   ifdef THREE86BSD
+#	define OS_TYPE "THREE86BSD"
+#   endif
+#   ifdef BSDI
+#	define OS_TYPE "BSDI"
+#   endif
+#   if defined(OPENBSD) || defined(FREEBSD) || defined(NETBSD) \
+        || defined(THREE86BSD) || defined(BSDI)
+#	define HEURISTIC2
+	extern char etext;
+#	define DATASTART ((ptr_t)(&etext))
+#   endif
+#   ifdef NEXT
+#	define OS_TYPE "NEXT"
+#	define DATASTART ((ptr_t) get_etext())
+#	define STACKBOTTOM ((ptr_t)0xc0000000)
+#	define DATAEND	/* not needed */
+#   endif
+#   ifdef DOS4GW
+#     define OS_TYPE "DOS4GW"
+      extern long __nullarea;
+      extern char _end;
+      extern char *_STACKTOP;
+      /* Depending on calling conventions Watcom C either precedes
+         or does not precedes with undescore names of C-variables.
+         Make sure startup code variables always have the same names.  */
+      #pragma aux __nullarea "*";
+      #pragma aux _end "*";
+#     define STACKBOTTOM ((ptr_t) _STACKTOP)
+                         /* confused? me too. */
+#     define DATASTART ((ptr_t) &__nullarea)
+#     define DATAEND ((ptr_t) &_end)
+#   endif
+# endif
+
+# ifdef NS32K
+#   define MACH_TYPE "NS32K"
+#   define ALIGNMENT 4
+    extern char **environ;
+#   define DATASTART ((ptr_t)(&environ))
+			      /* hideous kludge: environ is the first   */
+			      /* word in crt0.o, and delimits the start */
+			      /* of the data segment, no matter which   */
+			      /* ld options were passed through.        */
+#   define STACKBOTTOM ((ptr_t) 0xfffff000) /* for Encore */
+# endif
+
+# ifdef MIPS
+#   define MACH_TYPE "MIPS"
+#   ifndef IRIX5
+#     define DATASTART (ptr_t)0x10000000
+			      /* Could probably be slightly higher since */
+			      /* startup code allocates lots of stuff.   */
+#   else
+      extern int _fdata;
+#     define DATASTART ((ptr_t)(&_fdata))
+#     ifdef USE_MMAP
+#         define HEAP_START (ptr_t)0x30000000
+#     else
+#	  define HEAP_START DATASTART
+#     endif
+			      /* Lowest plausible heap address.		*/
+			      /* In the MMAP case, we map there.	*/
+			      /* In either case it is used to identify	*/
+			      /* heap sections so they're not 		*/
+			      /* considered as roots.			*/
+#   endif /* IRIX5 */
+#   define HEURISTIC2
+/* #   define STACKBOTTOM ((ptr_t)0x7fff8000)  sometimes also works.  */
+#   ifdef ULTRIX
+#	define OS_TYPE "ULTRIX"
+#       define ALIGNMENT 4
+#   endif
+#   ifdef RISCOS
+#	define OS_TYPE "RISCOS"
+#   	define ALIGNMENT 4  /* Required by hardware */
+#   endif
+#   ifdef IRIX5
+#	define OS_TYPE "IRIX5"
+#       define MPROTECT_VDB
+#       ifdef _MIPS_SZPTR
+#	  define CPP_WORDSZ _MIPS_SZPTR
+#	  define ALIGNMENT (_MIPS_SZPTR/8)
+#	  if CPP_WORDSZ != 64
+#	    define ALIGN_DOUBLE
+#	  endif
+#	else
+#         define ALIGNMENT 4
+#	  define ALIGN_DOUBLE
+#	endif
+#	define DYNAMIC_LOADING
+#   endif
+# endif
+
+# ifdef RS6000
+#   define MACH_TYPE "RS6000"
+#   define ALIGNMENT 4
+#   define DATASTART ((ptr_t)0x20000000)
+    extern int errno;
+#   define STACKBOTTOM ((ptr_t)((ulong)&errno))
+#   define DYNAMIC_LOADING
+	/* For really old versions of AIX, this may have to be removed. */
+# endif
+
+# ifdef HP_PA
+#   define MACH_TYPE "HP_PA"
+#   define ALIGNMENT 4
+#   define ALIGN_DOUBLE
+    extern int __data_start;
+#   define DATASTART ((ptr_t)(&__data_start))
+#   if 0
+	/* The following appears to work for 7xx systems running HP/UX	*/
+	/* 9.xx Furthermore, it might result in much faster		*/
+	/* collections than HEURISTIC2, which may involve scanning	*/
+	/* segments that directly precede the stack.  It is not the	*/
+	/* default, since it may not work on older machine/OS		*/
+	/* combinations. (Thanks to Raymond X.T. Nijssen for uncovering	*/
+	/* this.)							*/
+#       define STACKBOTTOM ((ptr_t) 0x7b033000)  /* from /etc/conf/h/param.h */
+#   else
+#       define HEURISTIC2
+#   endif
+#   define STACK_GROWS_UP
+#   define DYNAMIC_LOADING
+#   include <unistd.h>
+#   define GETPAGESIZE() sysconf(_SC_PAGE_SIZE)
+	/* They misspelled the Posix macro?	*/
+# endif
+
+# ifdef ALPHA
+#   define MACH_TYPE "ALPHA"
+#   define ALIGNMENT 8
+#   ifdef OSF1
+#	define OS_TYPE "OSF1"
+#   	define DATASTART ((ptr_t) 0x140000000)
+	extern _end;
+#   	define DATAEND ((ptr_t) &_end)
+#   	define HEURISTIC2
+	/* Normally HEURISTIC2 is too conervative, since		*/
+	/* the text segment immediately follows the stack.		*/
+	/* Hence we give an upper pound.				*/
+    	extern int __start;
+#   	define HEURISTIC2_LIMIT ((ptr_t)((word)(&__start) & ~(getpagesize()-1)))
+#   	define CPP_WORDSZ 64
+#   	define MPROTECT_VDB
+#   	define DYNAMIC_LOADING
+#   endif
+#   ifdef LINUX
+#       define OS_TYPE "LINUX"
+#       define CPP_WORDSZ 64
+#       define STACKBOTTOM ((ptr_t) 0x120000000)
+#       ifdef __ELF__
+#   	  if 0
+	    /* __data_start apparently disappeared in some recent releases. */
+            extern int __data_start;
+#           define DATASTART &__data_start
+#	  endif
+#         define DATASTART GC_data_start
+#         define DYNAMIC_LOADING
+#       else
+#           define DATASTART ((ptr_t) 0x140000000)
+#       endif
+	extern int _end;
+#	define DATAEND (&_end)
+#	define MPROTECT_VDB
+		/* Has only been superficially tested.  May not	*/
+		/* work on all versions.			*/
+#   endif
+# endif
+
+# ifdef M88K
+#   define MACH_TYPE "M88K"
+#   define ALIGNMENT 4
+#   define ALIGN_DOUBLE
+    extern int etext;
+#   ifdef CX_UX
+#	define OS_TYPE "CX_UX"
+#       define DATASTART ((((word)&etext + 0x3fffff) & ~0x3fffff) + 0x10000)
+#   endif
+#   ifdef  DGUX
+#	define OS_TYPE "DGUX"
+	extern char * GC_SysVGetDataStart();
+#       define DATASTART (ptr_t)GC_SysVGetDataStart(0x10000, &etext)
+#   endif
+#   define STACKBOTTOM ((char*)0xf0000000) /* determined empirically */
+# endif
+
+# ifdef S370
+#   define MACH_TYPE "S370"
+#   define OS_TYPE "UTS4"
+#   define ALIGNMENT 4	/* Required by hardware	*/
+    extern int etext;
+	extern int _etext;
+	extern int _end;
+	extern char * GC_SysVGetDataStart();
+#       define DATASTART (ptr_t)GC_SysVGetDataStart(0x10000, &_etext)
+#	define DATAEND (&_end)
+#	define HEURISTIC2
+# endif
+
+# ifndef STACK_GROWS_UP
+#   define STACK_GROWS_DOWN
+# endif
+
+# ifndef CPP_WORDSZ
+#   define CPP_WORDSZ 32
+# endif
+
+# ifndef OS_TYPE
+#   define OS_TYPE ""
+# endif
+
+# ifndef DATAEND
+    extern int end;
+#   define DATAEND (&end)
+# endif
+
+# if defined(SVR4) && !defined(GETPAGESIZE)
+#    include <unistd.h>
+#    define GETPAGESIZE()  sysconf(_SC_PAGESIZE)
+# endif
+
+# ifndef GETPAGESIZE
+#   if defined(SUNOS5) || defined(IRIX5)
+#	include <unistd.h>
+#   endif
+#   define GETPAGESIZE() getpagesize()
+# endif
+
+# if defined(SUNOS5) || defined(DRSNX) || defined(UTS4)
+    /* OS has SVR4 generic features.  Probably others also qualify.	*/
+#   define SVR4
+# endif
+
+# if defined(SUNOS5) || defined(DRSNX)
+    /* OS has SUNOS5 style semi-undocumented interface to dynamic 	*/
+    /* loader.								*/
+#   define SUNOS5DL
+    /* OS has SUNOS5 style signal handlers.				*/
+#   define SUNOS5SIGS
+# endif
+
+# if CPP_WORDSZ != 32 && CPP_WORDSZ != 64
+   -> bad word size
+# endif
+
+# ifdef PCR
+#   undef DYNAMIC_LOADING
+#   undef STACKBOTTOM
+#   undef HEURISTIC1
+#   undef HEURISTIC2
+#   undef PROC_VDB
+#   undef MPROTECT_VDB
+#   define PCR_VDB
+# endif
+
+# ifdef SRC_M3
+/* Postponed for now. */
+#   undef PROC_VDB
+#   undef MPROTECT_VDB
+# endif
+
+# ifdef SMALL_CONFIG
+/* Presumably not worth the space it takes. */
+#   undef PROC_VDB
+#   undef MPROTECT_VDB
+# endif
+
+# ifdef USE_MUNMAP
+#   undef MPROTECT_VDB  /* Can't deal with address space holes. */
+# endif
+
+# if !defined(PCR_VDB) && !defined(PROC_VDB) && !defined(MPROTECT_VDB)
+#   define DEFAULT_VDB
+# endif
+
+# if defined(_SOLARIS_PTHREADS) && !defined(SOLARIS_THREADS)
+#   define SOLARIS_THREADS
+# endif
+# if defined(IRIX_THREADS) && !defined(IRIX5)
+--> inconsistent configuration
+# endif
+# if defined(IRIX_JDK_THREADS) && !defined(IRIX5)
+--> inconsistent configuration
+# endif
+# if defined(LINUX_THREADS) && !defined(LINUX)
+--> inconsistent configuration
+# endif
+# if defined(SOLARIS_THREADS) && !defined(SUNOS5)
+--> inconsistent configuration
+# endif
+# if defined(PCR) || defined(SRC_M3) || \
+	defined(SOLARIS_THREADS) || defined(WIN32_THREADS) || \
+	defined(IRIX_THREADS) || defined(LINUX_THREADS) || \
+	defined(IRIX_JDK_THREADS)
+#   define THREADS
+# endif
+
+# if defined(HP_PA) || defined(M88K) || defined(POWERPC) \
+     || (defined(I386) && defined(OS2)) || defined(UTS4) || defined(LINT)
+	/* Use setjmp based hack to mark from callee-save registers. */
+#	define USE_GENERIC_PUSH_REGS
+# endif
+# if defined(SPARC) && !defined(LINUX)
+#   define SAVE_CALL_CHAIN
+#   define ASM_CLEAR_CODE	/* Stack clearing is crucial, and we 	*/
+				/* include assembly code to do it well.	*/
+# endif
+
+# endif