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Annotation of OpenXM_contrib/gc/setjmp_t.c, Revision 1.1

1.1     ! maekawa     1: /*
        !             2:  * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
        !             3:  *
        !             4:  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
        !             5:  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
        !             6:  *
        !             7:  * Permission is hereby granted to use or copy this program
        !             8:  * for any purpose,  provided the above notices are retained on all copies.
        !             9:  * Permission to modify the code and to distribute modified code is granted,
        !            10:  * provided the above notices are retained, and a notice that the code was
        !            11:  * modified is included with the above copyright notice.
        !            12:  */
        !            13: /* Boehm, September 21, 1995 5:39 pm PDT */
        !            14:
        !            15: /* Check whether setjmp actually saves registers in jmp_buf. */
        !            16: /* If it doesn't, the generic mark_regs code won't work.     */
        !            17: /* Compilers vary as to whether they will put x in a        */
        !            18: /* (callee-save) register without -O.  The code is          */
        !            19: /* contrived such that any decent compiler should put x in   */
        !            20: /* a callee-save register with -O.  Thus it is is           */
        !            21: /* recommended that this be run optimized.  (If the machine  */
        !            22: /* has no callee-save registers, then the generic code is    */
        !            23: /* safe, but this will not be noticed by this piece of       */
        !            24: /* code.)                                                   */
        !            25: #include <stdio.h>
        !            26: #include <setjmp.h>
        !            27: #include <string.h>
        !            28: #include "gcconfig.h"
        !            29:
        !            30: #ifdef OS2
        !            31: /* GETPAGESIZE() is set to getpagesize() by default, but that  */
        !            32: /* doesn't really exist, and the collector doesn't need it.    */
        !            33: #define INCL_DOSFILEMGR
        !            34: #define INCL_DOSMISC
        !            35: #define INCL_DOSERRORS
        !            36: #include <os2.h>
        !            37:
        !            38: int
        !            39: getpagesize()
        !            40: {
        !            41:     ULONG result[1];
        !            42:
        !            43:     if (DosQuerySysInfo(QSV_PAGE_SIZE, QSV_PAGE_SIZE,
        !            44:                        (void *)result, sizeof(ULONG)) != NO_ERROR) {
        !            45:        fprintf(stderr, "DosQuerySysInfo failed\n");
        !            46:        result[0] = 4096;
        !            47:     }
        !            48:     return((int)(result[0]));
        !            49: }
        !            50: #endif
        !            51:
        !            52: struct {char a_a; char * a_b;} a;
        !            53:
        !            54: int * nested_sp()
        !            55: {
        !            56:     int dummy;
        !            57:
        !            58:     return(&dummy);
        !            59: }
        !            60:
        !            61: main()
        !            62: {
        !            63:        int dummy;
        !            64:        long ps = GETPAGESIZE();
        !            65:        jmp_buf b;
        !            66:        register int x = (int)strlen("a");  /* 1, slightly disguised */
        !            67:        static int y = 0;
        !            68:
        !            69:        printf("This appears to be a %s running %s\n", MACH_TYPE, OS_TYPE);
        !            70:        if (nested_sp() < &dummy) {
        !            71:          printf("Stack appears to grow down, which is the default.\n");
        !            72:          printf("A good guess for STACKBOTTOM on this machine is 0x%lx.\n",
        !            73:                 ((unsigned long)(&dummy) + ps) & ~(ps-1));
        !            74:        } else {
        !            75:          printf("Stack appears to grow up.\n");
        !            76:          printf("Define STACK_GROWS_UP in gc_private.h\n");
        !            77:          printf("A good guess for STACKBOTTOM on this machine is 0x%lx.\n",
        !            78:                 ((unsigned long)(&dummy) + ps) & ~(ps-1));
        !            79:        }
        !            80:        printf("Note that this may vary between machines of ostensibly\n");
        !            81:        printf("the same architecture (e.g. Sun 3/50s and 3/80s).\n");
        !            82:        printf("On many machines the value is not fixed.\n");
        !            83:        printf("A good guess for ALIGNMENT on this machine is %ld.\n",
        !            84:               (unsigned long)(&(a.a_b))-(unsigned long)(&a));
        !            85:
        !            86:        /* Encourage the compiler to keep x in a callee-save register */
        !            87:        x = 2*x-1;
        !            88:        printf("");
        !            89:        x = 2*x-1;
        !            90:        setjmp(b);
        !            91:        if (y == 1) {
        !            92:            if (x == 2) {
        !            93:                printf("Generic mark_regs code probably wont work\n");
        !            94: #              if defined(SPARC) || defined(RS6000) || defined(VAX) || defined(MIPS) || defined(M68K) || defined(I386) || defined(NS32K) || defined(RT)
        !            95:                    printf("Assembly code supplied\n");
        !            96: #              else
        !            97:                    printf("Need assembly code\n");
        !            98: #              endif
        !            99:            } else if (x == 1) {
        !           100:                printf("Generic mark_regs code may work\n");
        !           101:            } else {
        !           102:                printf("Very strange setjmp implementation\n");
        !           103:            }
        !           104:        }
        !           105:        y++;
        !           106:        x = 2;
        !           107:        if (y == 1) longjmp(b,1);
        !           108:        return(0);
        !           109: }
        !           110:
        !           111: int g(x)
        !           112: int x;
        !           113: {
        !           114:        return(x);
        !           115: }