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diff --git a/gc/doc/README.amiga b/gc/doc/README.amiga deleted file mode 100644 index 730dce3..0000000 --- a/gc/doc/README.amiga +++ /dev/null @@ -1,322 +0,0 @@ -=========================================================================== - Kjetil S. Matheussen's notes (28-11-2000) -=========================================================================== -Compiles under SAS/C again. Should allso still compile under other -amiga compilers without big changes. I haven't checked if it still -works under gcc, because I don't have gcc for amiga. But I have -updated 'Makefile', and hope it compiles fine. - - -WHATS NEW: - -1. - Made a pretty big effort in preventing GCs allocating-functions from returning - chip-mem. - - The lower part of the new file AmigaOS.c does this in various ways, mainly by - wrapping GC_malloc, GC_malloc_atomic, GC_malloc_uncollectable, - GC_malloc_atomic_uncollectable, GC_malloc_stubborn, GC_malloc_ignore_off_page - and GC_malloc_atomic_ignore_off_page. GC_realloc is allso wrapped, but - doesn't do the same effort in preventing to return chip-mem. - Other allocating-functions (f.ex. GC_*_typed_) can probably be - used without any problems, but beware that the warn hook will not be called. - In case of problems, don't define GC_AMIGA_FASTALLOC. - - Programs using more time actually using the memory allocated - (instead of just allocate and free rapidly) have - the most to earn on this, but even gctest now normally runs twice - as fast and uses less memory, on my poor 8MB machine. - - The changes have only effect when there is no more - fast-mem left. But with the way GC works, it - could happen quite often. Beware that an atexit handler had to be added, - so using the abort() function will make a big memory-loss. - If you absolutely must call abort() instead of exit(), try calling - the GC_amiga_free_all_mem function before abort(). - - New amiga-spesific compilation flags: - - GC_AMIGA_FASTALLOC - By NOT defining this option, GC will work like before, - it will not try to force fast-mem out of the OS, and - it will use normal calloc for allocation, and the rest - of the following flags will have no effect. - - GC_AMIGA_ONLYFAST - Makes GC never to return chip-mem. GC_AMIGA_RETRY have - no effect if this flag is set. - - GC_AMIGA_GC - If gc returns NULL, do a GC_gcollect, and try again. This - usually is a success with the standard GC configuration. - It is allso the most important flag to set to prevent - GC from returning chip-mem. Beware that it slows down a lot - when a program is rapidly allocating/deallocating when - theres either very little fast-memory left or verly little - chip-memory left. Its not a very common situation, but gctest - sometimes (very rare) use many minutes because of this. - - GC_AMIGA_RETRY - If gc succeed allocating memory, but it is chip-mem, - try again and see if it is fast-mem. Most of the time, - it will actually return fast-mem for the second try. - I have set max number of retries to 9 or size/5000. You - can change this if you like. (see GC_amiga_rec_alloc()) - - GC_AMIGA_PRINTSTATS - Gather some statistics during the execution of a - program, and prints out the info when the atexit-handler - is called. - - My reccomendation is to set all this flags, except GC_AMIGA_PRINTSTATS and - GC_AMIGA_ONLYFAST. - - If your program demands high response-time, you should - not define GC_AMIGA_GC, and possible allso define GC_AMIGA_ONLYFAST. - GC_AMIGA_RETRY does not seem to slow down much. - - Allso, when compiling up programs, and GC_AMIGA_FASTALLOC was not defined when - compilling gc, you can define GC_AMIGA_MAKINGLIB to avoid having these allocation- - functions wrapped. (see gc.h) - - Note that GC_realloc must not be called before any of - the other above mentioned allocating-functions have been called. (shouldn't be - any programs doing so either, I hope). - - Another note. The allocation-function is wrapped when defining - GC_AMIGA_FASTALLOC by letting the function go thru the new - GC_amiga_allocwrapper_do function-pointer (see gc.h). Means that - sending function-pointers, such as GC_malloc, GC_malloc_atomic, etc., - for later to be called like f.ex this, (*GC_malloc_functionpointer)(size), - will not wrap the function. This is normally not a big problem, unless - all allocation function is called like this, which will cause the - atexit un-allocating function never to be called. Then you either - have to manually add the atexit handler, or call the allocation- - functions function-pointer functions like this; - (*GC_amiga_allocwrapper_do)(size,GC_malloc_functionpointer). - There are probably better ways this problem could be handled, unfortunately, - I didn't find any without rewriting or replacing a lot of the GC-code, which - I really didn't want to. (Making new GC_malloc_* functions, and just - define f.ex GC_malloc as GC_amiga_malloc should allso work). - - - New amiga-spesific function: - - void GC_amiga_set_toany(void (*func)(void)); - - 'func' is a function that will be called right before gc has to change - allocation-method from MEMF_FAST to MEMF_ANY. Ie. when it is likely - it will return chip-mem. - - -2. A few small compiler-spesific additions to make it compile with SAS/C again. - -3. Updated and rewritten the smakefile, so that it works again and that - the "unnecesarry" 'SCOPTIONS' files could be removed. Allso included - the cord-smakefile stuff in the main smakefile, so that the cord smakefile - could be removed too. By writing smake -f Smakefile.smk, both gc.lib and - cord.lib will be made. - - - -STILL MISSING: - -Programs can not be started from workbench, at least not for SAS/C. (Martin -Tauchmanns note about that it now works with workbench is definitely wrong -when concerning SAS/C). I guess it works if you use the old "#if 0'ed"-code, -but I haven't tested it. I think the reason for MT to replace the -"#if 0'ed"-code was only because it was a bit to SAS/C-spesific. But I -don't know. An iconx-script solves this problem anyway. - - -BEWARE! - --To run gctest, set the stack to around 200000 bytes first. --SAS/C-spesific: cord will crash if you compile gc.lib with - either parm=reg or parm=both. (missing legal prototypes for - function-pointers someplace is the reason I guess.). - - -tested with software: Radium, http://www.stud.ifi.uio.no/~ksvalast/radium/ - -tested with hardware: MC68060 - - --ksvalast@ifi.uio.no - - -=========================================================================== - Martin Tauchmann's notes (1-Apr-99) -=========================================================================== - -Works now, also with the GNU-C compiler V2.7.2.1. <ftp://ftp.unina.it/pub/amiga/geekgadgets/amiga/m68k/snapshots/971125/amiga-bin/> -Modify the `Makefile` -CC=cc $(ABI_FLAG) -to -CC=gcc $(ABI_FLAG) - -TECHNICAL NOTES - -- `GC_get_stack_base()`, `GC_register_data_segments()` works now with every - C compiler; also Workbench. - -- Removed AMIGA_SKIP_SEG, but the Code-Segment must not be scanned by GC. - - -PROBLEMS -- When the Linker, does`t merge all Code-Segments to an single one. LD of GCC - do it always. - -- With ixemul.library V47.3, when an GC program launched from another program - (example: `Make` or `if_mach M68K AMIGA gctest`), `GC_register_data_segments()` - found the Segment-List of the caller program. - Can be fixed, if the run-time initialization code (for C programs, usually *crt0*) - support `__data` and `__bss`. - -- PowerPC Amiga currently not supported. - -- Dynamic libraries (dyn_load.c) not supported. - - -TESTED WITH SOFTWARE - -`Optimized Oberon 2 C` (oo2c) <http://cognac.informatik.uni-kl.de/download/index.html> - - -TESTED WITH HARDWARE - -MC68030 - - -CONTACT - -Please, contact me at <martintauchmann@bigfoot.com>, when you change the -Amiga port. <http://martintauchmann.home.pages.de> - -=========================================================================== - Michel Schinz's notes -=========================================================================== -WHO DID WHAT - -The original Amiga port was made by Jesper Peterson. I (Michel Schinz) -modified it slightly to reflect the changes made in the new official -distributions, and to take advantage of the new SAS/C 6.x features. I also -created a makefile to compile the "cord" package (see the cord -subdirectory). - -TECHNICAL NOTES - -In addition to Jesper's notes, I have the following to say: - -- Starting with version 4.3, gctest checks to see if the code segment is - added to the root set or not, and complains if it is. Previous versions - of this Amiga port added the code segment to the root set, so I tried to - fix that. The only problem is that, as far as I know, it is impossible to - know which segments are code segments and which are data segments (there - are indeed solutions to this problem, like scanning the program on disk - or patch the LoadSeg functions, but they are rather complicated). The - solution I have chosen (see os_dep.c) is to test whether the program - counter is in the segment we are about to add to the root set, and if it - is, to skip the segment. The problems are that this solution is rather - awkward and that it works only for one code segment. This means that if - your program has more than one code segment, all of them but one will be - added to the root set. This isn't a big problem in fact, since the - collector will continue to work correctly, but it may be slower. - - Anyway, the code which decides whether to skip a segment or not can be - removed simply by not defining AMIGA_SKIP_SEG. But notice that if you do - so, gctest will complain (it will say that "GC_is_visible produced wrong - failure indication"). However, it may be useful if you happen to have - pointers stored in a code segment (you really shouldn't). - - If anyone has a good solution to the problem of finding, when a program - is loaded in memory, whether a segment is a code or a data segment, - please let me know. - -PROBLEMS - -If you have any problem with this version, please contact me at -schinz@alphanet.ch (but do *not* send long files, since we pay for -every mail!). - -=========================================================================== - Jesper Peterson's notes -=========================================================================== - -ADDITIONAL NOTES FOR AMIGA PORT - -These notes assume some familiarity with Amiga internals. - -WHY I PORTED TO THE AMIGA - -The sole reason why I made this port was as a first step in getting -the Sather(*) language on the Amiga. A port of this language will -be done as soon as the Sather 1.0 sources are made available to me. -Given this motivation, the garbage collection (GC) port is rather -minimal. - -(*) For information on Sather read the comp.lang.sather newsgroup. - -LIMITATIONS - -This port assumes that the startup code linked with target programs -is that supplied with SAS/C versions 6.0 or later. This allows -assumptions to be made about where to find the stack base pointer -and data segments when programs are run from WorkBench, as opposed -to running from the CLI. The compiler dependent code is all in the -GC_get_stack_base() and GC_register_data_segments() functions, but -may spread as I add Amiga specific features. - -Given that SAS/C was assumed, the port is set up to be built with -"smake" using the "SMakefile". Compiler options in "SCoptions" can -be set with "scopts" program. Both "smake" and "scopts" are part of -the SAS/C commercial development system. - -In keeping with the porting philosophy outlined above, this port -will not behave well with Amiga specific code. Especially not inter- -process comms via messages, and setting up public structures like -Intuition objects or anything else in the system lists. For the -time being the use of this library is limited to single threaded -ANSI/POSIX compliant or near-complient code. (ie. Stick to stdio -for now). Given this limitation there is currently no mechanism for -allocating "CHIP" or "PUBLIC" memory under the garbage collector. -I'll add this after giving it considerable thought. The major -problem is the entire physical address space may have to me scanned, -since there is no telling who we may have passed memory to. - -If you allocate your own stack in client code, you will have to -assign the pointer plus stack size to GC_stackbottom. - -The initial stack size of the target program can be compiled in by -setting the __stack symbol (see SAS documentaion). It can be over- -ridden from the CLI by running the AmigaDOS "stack" program, or from -the WorkBench by setting the stack size in the tool types window. - -SAS/C COMPILER OPTIONS (SCoptions) - -You may wish to check the "CPU" code option is appropriate for your -intended target system. - -Under no circumstances set the "StackExtend" code option in either -compiling the library or *ANY* client code. - -All benign compiler warnings have been suppressed. These mainly -involve lack of prototypes in the code, and dead assignments -detected by the optimizer. - -THE GOOD NEWS - -The library as it stands is compatible with the GigaMem commercial -virtual memory software, and probably similar PD software. - -The performance of "gctest" on an Amiga 2630 (68030 @ 25Mhz) -compares favourably with an HP9000 with similar architecture (a 325 -with a 68030 I think). - ------------------------------------------------------------------------ - -The Amiga port has been brought to you by: - -Jesper Peterson. - -jep@mtiame.mtia.oz.au (preferred, but 1 week turnaround) -jep@orca1.vic.design.telecom.au (that's orca<one>, 1 day turnaround) - -At least one of these addresses should be around for a while, even -though I don't work for either of the companies involved. - |