+# ifdef CRIS
+# define MACH_TYPE "CRIS"
+# define CPP_WORDSZ 32
+# define ALIGNMENT 1
+# define OS_TYPE "LINUX"
+# define DYNAMIC_LOADING
+# define LINUX_STACKBOTTOM
+# define USE_GENERIC_PUSH_REGS
+# define SEARCH_FOR_DATA_START
+ extern int _end[];
+# define DATAEND (_end)
+# endif
+
+# ifdef SH
+# define MACH_TYPE "SH"
+# define ALIGNMENT 4
+# ifdef MSWINCE
+# define OS_TYPE "MSWINCE"
+# define DATAEND /* not needed */
+# endif
+# ifdef LINUX
+# define OS_TYPE "LINUX"
+# define LINUX_STACKBOTTOM
+# define USE_GENERIC_PUSH_REGS
+# define DYNAMIC_LOADING
+# define SEARCH_FOR_DATA_START
+ extern int _end[];
+# define DATAEND (_end)
+# endif
+# ifdef NETBSD
+# define OS_TYPE "NETBSD"
+# define HEURISTIC2
+# define DATASTART GC_data_start
+# define USE_GENERIC_PUSH_REGS
+# define DYNAMIC_LOADING
+# endif
+# endif
+
+# ifdef SH4
+# define MACH_TYPE "SH4"
+# define OS_TYPE "MSWINCE"
+# define ALIGNMENT 4
+# define DATAEND /* not needed */
+# endif
+
+# ifdef M32R
+# define CPP_WORDSZ 32
+# define MACH_TYPE "M32R"
+# define ALIGNMENT 4
+# ifdef LINUX
+# define OS_TYPE "LINUX"
+# define LINUX_STACKBOTTOM
+# undef STACK_GRAN
+# define STACK_GRAN 0x10000000
+# define USE_GENERIC_PUSH_REGS
+# define DYNAMIC_LOADING
+# define SEARCH_FOR_DATA_START
+ extern int _end[];
+# define DATAEND (_end)
+# endif
+# endif
+
+# ifdef X86_64
+# define MACH_TYPE "X86_64"
+# define ALIGNMENT 8
+# define CPP_WORDSZ 64
+# ifndef HBLKSIZE
+# define HBLKSIZE 4096
+# endif
+# define CACHE_LINE_SIZE 64
+# define USE_GENERIC_PUSH_REGS
+# ifdef LINUX
+# define OS_TYPE "LINUX"
+# define LINUX_STACKBOTTOM
+# if !defined(GC_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>
+# define SEARCH_FOR_DATA_START
+ extern int _end[];
+# define DATAEND (_end)
+# else
+ extern int etext[];
+# define DATASTART ((ptr_t)((((word) (etext)) + 0xfff) & ~0xfff))
+# endif
+# if defined(__GNUC__) && __GNUC >= 3
+# define PREFETCH(x) __builtin_prefetch((x), 0, 0)
+# define PREFETCH_FOR_WRITE(x) __builtin_prefetch((x), 1)
+# endif
+# endif
+# ifdef DARWIN
+# define OS_TYPE "DARWIN"
+# define DARWIN_DONT_PARSE_STACK
+# define DYNAMIC_LOADING
+ /* XXX: see get_end(3), get_etext() and get_end() should not be used.
+ These aren't used when dyld support is enabled (it is by default) */
+# define DATASTART ((ptr_t) get_etext())
+# define DATAEND ((ptr_t) get_end())
+# ifdef HAVE_PTHREAD_GET_STACKADDR_NP
+# define STACKBOTTOM (ptr_t)pthread_get_stackaddr_np(pthread_self())
+# else
+# define STACKBOTTOM ((ptr_t) 0x7fff5fc00000)
+# endif
+# define USE_MMAP
+# define USE_MMAP_ANON
+# ifdef GC_DARWIN_THREADS
+# define MPROTECT_VDB
+# endif
+# include <unistd.h>
+# define GETPAGESIZE() getpagesize()
+ /* There seems to be some issues with trylock hanging on darwin. This
+ should be looked into some more */
+# define NO_PTHREAD_TRYLOCK
+# endif
+# ifdef FREEBSD
+# define OS_TYPE "FREEBSD"
+# ifndef GC_FREEBSD_THREADS
+# define MPROTECT_VDB
+# endif
+# ifdef __GLIBC__
+# define SIG_SUSPEND (32+6)
+# define SIG_THR_RESTART (32+5)
+ extern int _end[];
+# define DATAEND (_end)
+# else
+# define SIG_SUSPEND SIGUSR1
+# define SIG_THR_RESTART SIGUSR2
+# endif
+# define FREEBSD_STACKBOTTOM
+# ifdef __ELF__
+# define DYNAMIC_LOADING
+# endif
+ extern char etext[];
+ extern char * GC_FreeBSDGetDataStart();
+# define DATASTART GC_FreeBSDGetDataStart(0x1000, &etext)
+# endif
+# ifdef NETBSD
+# define OS_TYPE "NETBSD"
+# ifdef __ELF__
+# define DYNAMIC_LOADING
+# endif
+# define HEURISTIC2
+ extern char etext[];
+# define SEARCH_FOR_DATA_START
+# endif
+# ifdef SUNOS5
+# define ELF_CLASS ELFCLASS64
+# define OS_TYPE "SUNOS5"
+ extern int _etext[], _end[];
+ extern ptr_t GC_SysVGetDataStart();
+# define DATASTART GC_SysVGetDataStart(0x1000, _etext)
+# define DATAEND (_end)
+/* # define STACKBOTTOM ((ptr_t)(_start)) worked through 2.7, */
+/* but reportedly breaks under 2.8. It appears that the stack */
+/* base is a property of the executable, so this should not break */
+/* old executables. */
+/* HEURISTIC2 probably works, but this appears to be preferable. */
+/* # include <sys/vm.h> */
+/* # define STACKBOTTOM USRSTACK */
+# define HEURISTIC2
+# define PROC_VDB
+# define DYNAMIC_LOADING
+# if !defined(USE_MMAP) && defined(REDIRECT_MALLOC)
+# define USE_MMAP
+ /* Otherwise we now use calloc. Mmap may result in the */
+ /* heap interleaved with thread stacks, which can result in */
+ /* excessive blacklisting. Sbrk is unusable since it */
+ /* doesn't interact correctly with the system malloc. */
+# endif
+# ifdef USE_MMAP
+# define HEAP_START (ptr_t)0x40000000
+# else
+# define HEAP_START DATAEND
+# endif
+# endif
+# endif
+
+#if defined(LINUX) && defined(USE_MMAP)
+ /* The kernel may do a somewhat better job merging mappings etc. */
+ /* with anonymous mappings. */
+# define USE_MMAP_ANON