зеркало из https://github.com/mozilla/gecko-dev.git
116 строки
3.4 KiB
C
116 строки
3.4 KiB
C
/*
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* Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
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*
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* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
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* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
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*
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* Permission is hereby granted to use or copy this program
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* for any purpose, provided the above notices are retained on all copies.
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* Permission to modify the code and to distribute modified code is granted,
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* provided the above notices are retained, and a notice that the code was
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* modified is included with the above copyright notice.
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*/
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/* Boehm, September 21, 1995 5:39 pm PDT */
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/* Check whether setjmp actually saves registers in jmp_buf. */
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/* If it doesn't, the generic mark_regs code won't work. */
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/* Compilers vary as to whether they will put x in a */
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/* (callee-save) register without -O. The code is */
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/* contrived such that any decent compiler should put x in */
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/* a callee-save register with -O. Thus it is is */
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/* recommended that this be run optimized. (If the machine */
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/* has no callee-save registers, then the generic code is */
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/* safe, but this will not be noticed by this piece of */
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/* code.) */
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#include <stdio.h>
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#include <setjmp.h>
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#include <string.h>
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#include "gcconfig.h"
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#ifdef OS2
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/* GETPAGESIZE() is set to getpagesize() by default, but that */
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/* doesn't really exist, and the collector doesn't need it. */
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#define INCL_DOSFILEMGR
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#define INCL_DOSMISC
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#define INCL_DOSERRORS
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#include <os2.h>
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int
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getpagesize()
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{
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ULONG result[1];
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if (DosQuerySysInfo(QSV_PAGE_SIZE, QSV_PAGE_SIZE,
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(void *)result, sizeof(ULONG)) != NO_ERROR) {
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fprintf(stderr, "DosQuerySysInfo failed\n");
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result[0] = 4096;
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}
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return((int)(result[0]));
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}
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#endif
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struct {char a_a; char * a_b;} a;
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int * nested_sp()
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{
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int dummy;
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return(&dummy);
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}
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main()
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{
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int dummy;
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long ps = GETPAGESIZE();
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jmp_buf b;
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register int x = (int)strlen("a"); /* 1, slightly disguised */
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static int y = 0;
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printf("This appears to be a %s running %s\n", MACH_TYPE, OS_TYPE);
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if (nested_sp() < &dummy) {
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printf("Stack appears to grow down, which is the default.\n");
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printf("A good guess for STACKBOTTOM on this machine is 0x%lx.\n",
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((unsigned long)(&dummy) + ps) & ~(ps-1));
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} else {
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printf("Stack appears to grow up.\n");
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printf("Define STACK_GROWS_UP in gc_private.h\n");
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printf("A good guess for STACKBOTTOM on this machine is 0x%lx.\n",
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((unsigned long)(&dummy) + ps) & ~(ps-1));
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}
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printf("Note that this may vary between machines of ostensibly\n");
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printf("the same architecture (e.g. Sun 3/50s and 3/80s).\n");
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printf("On many machines the value is not fixed.\n");
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printf("A good guess for ALIGNMENT on this machine is %ld.\n",
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(unsigned long)(&(a.a_b))-(unsigned long)(&a));
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/* Encourage the compiler to keep x in a callee-save register */
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x = 2*x-1;
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printf("");
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x = 2*x-1;
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setjmp(b);
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if (y == 1) {
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if (x == 2) {
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printf("Generic mark_regs code probably wont work\n");
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# if defined(SPARC) || defined(RS6000) || defined(VAX) || defined(MIPS) || defined(M68K) || defined(I386) || defined(NS32K) || defined(RT)
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printf("Assembly code supplied\n");
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# else
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printf("Need assembly code\n");
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# endif
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} else if (x == 1) {
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printf("Generic mark_regs code may work\n");
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} else {
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printf("Very strange setjmp implementation\n");
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}
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}
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y++;
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x = 2;
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if (y == 1) longjmp(b,1);
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return(0);
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}
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int g(x)
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int x;
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{
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return(x);
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}
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