Annotation of OpenXM_contrib2/asir2000/gc/setjmp_t.c, Revision 1.2
1.1 noro 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:
14: /* Check whether setjmp actually saves registers in jmp_buf. */
15: /* If it doesn't, the generic mark_regs code won't work. */
16: /* Compilers vary as to whether they will put x in a */
17: /* (callee-save) register without -O. The code is */
18: /* contrived such that any decent compiler should put x in */
19: /* a callee-save register with -O. Thus it is is */
20: /* recommended that this be run optimized. (If the machine */
21: /* has no callee-save registers, then the generic code is */
22: /* safe, but this will not be noticed by this piece of */
1.2 ! noro 23: /* code.) This test appears to be far from perfect. */
1.1 noro 24: #include <stdio.h>
25: #include <setjmp.h>
26: #include <string.h>
1.2 ! noro 27: #include "private/gcconfig.h"
1.1 noro 28:
29: #ifdef OS2
30: /* GETPAGESIZE() is set to getpagesize() by default, but that */
31: /* doesn't really exist, and the collector doesn't need it. */
32: #define INCL_DOSFILEMGR
33: #define INCL_DOSMISC
34: #define INCL_DOSERRORS
35: #include <os2.h>
36:
37: int
38: getpagesize()
39: {
40: ULONG result[1];
41:
42: if (DosQuerySysInfo(QSV_PAGE_SIZE, QSV_PAGE_SIZE,
43: (void *)result, sizeof(ULONG)) != NO_ERROR) {
44: fprintf(stderr, "DosQuerySysInfo failed\n");
45: result[0] = 4096;
46: }
47: return((int)(result[0]));
48: }
49: #endif
50:
51: struct {char a_a; char * a_b;} a;
52:
53: int * nested_sp()
54: {
55: int dummy;
56:
57: return(&dummy);
58: }
59:
60: main()
61: {
62: int dummy;
63: long ps = GETPAGESIZE();
64: jmp_buf b;
65: register int x = (int)strlen("a"); /* 1, slightly disguised */
66: static int y = 0;
67:
68: printf("This appears to be a %s running %s\n", MACH_TYPE, OS_TYPE);
69: if (nested_sp() < &dummy) {
70: printf("Stack appears to grow down, which is the default.\n");
71: printf("A good guess for STACKBOTTOM on this machine is 0x%lx.\n",
72: ((unsigned long)(&dummy) + ps) & ~(ps-1));
73: } else {
74: printf("Stack appears to grow up.\n");
75: printf("Define STACK_GROWS_UP in gc_private.h\n");
76: printf("A good guess for STACKBOTTOM on this machine is 0x%lx.\n",
77: ((unsigned long)(&dummy) + ps) & ~(ps-1));
78: }
79: printf("Note that this may vary between machines of ostensibly\n");
80: printf("the same architecture (e.g. Sun 3/50s and 3/80s).\n");
81: printf("On many machines the value is not fixed.\n");
82: printf("A good guess for ALIGNMENT on this machine is %ld.\n",
83: (unsigned long)(&(a.a_b))-(unsigned long)(&a));
84:
85: /* Encourage the compiler to keep x in a callee-save register */
86: x = 2*x-1;
87: printf("");
88: x = 2*x-1;
89: setjmp(b);
90: if (y == 1) {
91: if (x == 2) {
92: printf("Generic mark_regs code probably wont work\n");
93: # if defined(SPARC) || defined(RS6000) || defined(VAX) || defined(MIPS) || defined(M68K) || defined(I386) || defined(NS32K) || defined(RT)
94: printf("Assembly code supplied\n");
95: # else
96: printf("Need assembly code\n");
97: # endif
98: } else if (x == 1) {
99: printf("Generic mark_regs code may work\n");
100: } else {
101: printf("Very strange setjmp implementation\n");
102: }
103: }
104: y++;
105: x = 2;
106: if (y == 1) longjmp(b,1);
107: return(0);
108: }
109:
110: int g(x)
111: int x;
112: {
113: return(x);
114: }
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