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+/*
+ * 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. */
+
+/* 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(__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)
+# 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)
+# define HP_PA
+# define mach_type_known
+# endif
+# if defined(linux) && defined(i386)
+# define I386
+# define LINUX
+# define mach_type_known
+# endif
+# if defined(linux) && defined(powerpc)
+# define POWERPC
+# define LINUX
+# define mach_type_known
+# endif
+# if defined(__alpha) || defined(__alpha__)
+# define ALPHA
+# if defined(linux) || defined(__linux__)
+# define LINUX
+# else
+# define OSF1 /* a.k.a Digital Unix */
+# endif
+# define mach_type_known
+# endif
+# if defined(_AMIGA)
+# define M68K
+# define AMIGA
+# 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(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(__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)
+# 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__)
+# 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 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 NETBSD
+# define OS_TYPE "NETBSD"
+# define HEURISTIC2
+ extern char etext;
+# define DATASTART ((ptr_t)(&etext))
+# 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"
+# define ALIGNMENT 2
+# 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 */
+# endif
+# ifdef LINUX
+# define OS_TYPE "LINUX"
+# define STACKBOTTOM ((ptr_t)0x80000000)
+# define DATASTART GC_data_start
+ extern int _end;
+# define DATAEND (&_end)
+# 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
+# define HEURISTIC1
+# include <unistd.h>
+# define GETPAGESIZE() sysconf(_SC_PAGESIZE)
+ /* getpagesize() appeared to be missing from at least one */
+ /* Solaris 5.4 installation. Weird. */
+# 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
+# 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)
+# endif
+# define DYNAMIC_LOADING
+# 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 STACKBOTTOM ((ptr_t)0xc0000000)
+ /* Appears to be 0xe0000000 for at least one 2.1.91 kernel. */
+ /* Probably needs to be more flexible, but I don't yet */
+ /* fully understand how flexible. */
+# define MPROTECT_VDB
+# ifdef __ELF__
+# define DYNAMIC_LOADING
+# ifdef UNDEFINED /* includes ro data */
+ extern int _etext;
+# define DATASTART ((ptr_t)((((word) (&_etext)) + 0xfff) & ~0xfff))
+# endif
+# include <linux/version.h>
+# include <features.h>
+# if LINUX_VERSION_CODE >= 0x20000 && 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
+ 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;
+# define DATASTART ((ptr_t)((((word) (&etext)) + 0x1ff) & ~0x1ff))
+# define STACKBOTTOM ((ptr_t)((word) _stubinfo + _stubinfo->size \
+ + _stklen))
+ /* This may not be right. */
+# 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(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"
+ /* Get_DATASTART, Get_DATAEND, Get_STACKBOTTOM
+ * Defined in gc-watcom.asm
+ */
+ extern char* Get_DATASTART (void);
+ extern char* Get_DATAEND (void);
+ extern char* Get_STACKBOTTOM (void);
+# pragma aux Get_DATASTART "*" value [eax];
+# pragma aux Get_DATAEND "*" value [eax];
+# pragma aux Get_STACKBOTTOM "*" value [eax];
+# define DATASTART ((ptr_t) Get_DATASTART())
+# define STACKBOTTOM ((ptr_t) Get_STACKBOTTOM())
+# define DATAEND ((ptr_t) Get_DATAEND())
+# 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)
+# define HEURISTIC2
+ /* Normally HEURISTIC2 is too conervative, since */
+ /* the text segment immediately follows the stack. */
+ /* Hence we give an upper pound. */
+ extern __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__
+ extern int __data_start;
+# define DATASTART &__data_start
+# define DYNAMIC_LOADING
+# else
+# define DATASTART ((ptr_t) 0x140000000)
+# endif
+ extern int _end;
+# define DATAEND (&_end)
+ /* As of 1.3.90, I couldn't find a way to retrieve the correct */
+ /* fault address from a signal handler. */
+ /* Hence MPROTECT_VDB is broken. */
+# 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
+
+# if !defined(PCR_VDB) && !defined(PROC_VDB) && !defined(MPROTECT_VDB)
+# define DEFAULT_VDB
+# endif
+
+# if defined(IRIX_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)
+# define THREADS
+# endif
+
+# if defined(SPARC)
+# define SAVE_CALL_CHAIN
+# define ASM_CLEAR_CODE /* Stack clearing is crucial, and we */
+ /* include assembly code to do it well. */
+# endif
+
+# endif