1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
|
/* NOCW */
/* sgibug.c */
/* bug found by Eric Young (eay@mincom.oz.au) May 95 */
#include <stdio.h>
/*
* This compiler bug it present on IRIX 5.3, 5.1 and 4.0.5 (these are the
* only versions of IRIX I have access to. defining FIXBUG removes the bug.
* (bug is still present in IRIX 6.3 according to Gage
* <agage@forgetmenot.Mines.EDU>
*/
/*-
* Compare the output from
* cc sgiccbug.c; ./a.out
* and
* cc -O sgiccbug.c; ./a.out
*/
static unsigned long a[4] =
{ 0x01234567, 0x89ABCDEF, 0xFEDCBA98, 0x76543210 };
static unsigned long b[4] =
{ 0x89ABCDEF, 0xFEDCBA98, 0x76543210, 0x01234567 };
static unsigned long c[4] =
{ 0x77777778, 0x8ACF1357, 0x88888888, 0x7530ECA9 };
main()
{
unsigned long r[4];
sub(r, a, b);
fprintf(stderr, "input a= %08X %08X %08X %08X\n", a[3], a[2], a[1], a[0]);
fprintf(stderr, "input b= %08X %08X %08X %08X\n", b[3], b[2], b[1], b[0]);
fprintf(stderr, "output = %08X %08X %08X %08X\n", r[3], r[2], r[1], r[0]);
fprintf(stderr, "correct= %08X %08X %08X %08X\n", c[3], c[2], c[1], c[0]);
}
int sub(r, a, b)
unsigned long *r, *a, *b;
{
register unsigned long t1, t2, *ap, *bp, *rp;
int i, carry;
#ifdef FIXBUG
unsigned long dummy;
#endif
ap = a;
bp = b;
rp = r;
carry = 0;
for (i = 0; i < 4; i++) {
t1 = *(ap++);
t2 = *(bp++);
t1 = (t1 - t2);
#ifdef FIXBUG
dummy = t1;
#endif
*(rp++) = t1 & 0xffffffff;
}
}
|
