Initial revision

1 files changed, 1110 insertions, 0 deletions

diff --git a/gc/gcconfig.h b/gc/gcconfig.h
new file mode 100644
index 0000000..189b13d
--- /dev/null
+++ b/gc/gcconfig.h
@@ -0,0 +1,1110 @@
+/* 
+ * 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(LINUX)
+#	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
+#    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"
+#   ifdef LINUX
+#     define OS_TYPE "LINUX"
+      extern int __data_start;
+#     define DATASTART ((ptr_t)(&__data_start))
+#     define ALIGNMENT 4
+#     define USE_GENERIC_PUSH_REGS 1
+#     define STACKBOTTOM 0x80000000
+#   else // LINUX
+#   ifndef IRIX5
+#     define DATASTART (ptr_t)0x10000000
+			      /* Could probably be slightly higher since */
+			      /* startup code allocates lots of stuff.   */
+#     else // IRIX5
+      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 // LINUX
+# 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