60 lines
1.4 KiB
C
60 lines
1.4 KiB
C
/* NOCW */
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/* sgibug.c */
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/* bug found by Eric Young (eay@mincom.oz.au) May 95 */
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#include <stdio.h>
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/*
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* This compiler bug it present on IRIX 5.3, 5.1 and 4.0.5 (these are the
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* only versions of IRIX I have access to. defining FIXBUG removes the bug.
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* (bug is still present in IRIX 6.3 according to Gage
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* <agage@forgetmenot.Mines.EDU>
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*/
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/*-
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* Compare the output from
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* cc sgiccbug.c; ./a.out
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* and
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* cc -O sgiccbug.c; ./a.out
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*/
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static unsigned long a[4] =
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{ 0x01234567, 0x89ABCDEF, 0xFEDCBA98, 0x76543210 };
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static unsigned long b[4] =
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{ 0x89ABCDEF, 0xFEDCBA98, 0x76543210, 0x01234567 };
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static unsigned long c[4] =
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{ 0x77777778, 0x8ACF1357, 0x88888888, 0x7530ECA9 };
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main()
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{
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unsigned long r[4];
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sub(r, a, b);
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fprintf(stderr, "input a= %08X %08X %08X %08X\n", a[3], a[2], a[1], a[0]);
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fprintf(stderr, "input b= %08X %08X %08X %08X\n", b[3], b[2], b[1], b[0]);
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fprintf(stderr, "output = %08X %08X %08X %08X\n", r[3], r[2], r[1], r[0]);
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fprintf(stderr, "correct= %08X %08X %08X %08X\n", c[3], c[2], c[1], c[0]);
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}
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int sub(r, a, b)
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unsigned long *r, *a, *b;
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{
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register unsigned long t1, t2, *ap, *bp, *rp;
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int i, carry;
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#ifdef FIXBUG
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unsigned long dummy;
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#endif
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ap = a;
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bp = b;
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rp = r;
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carry = 0;
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for (i = 0; i < 4; i++) {
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t1 = *(ap++);
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t2 = *(bp++);
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t1 = (t1 - t2);
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#ifdef FIXBUG
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dummy = t1;
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#endif
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*(rp++) = t1 & 0xffffffff;
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}
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}
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