diff options
Diffstat (limited to 'bugs/sgiccbug.c')
-rw-r--r-- | bugs/sgiccbug.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/bugs/sgiccbug.c b/bugs/sgiccbug.c new file mode 100644 index 0000000..178239d --- /dev/null +++ b/bugs/sgiccbug.c @@ -0,0 +1,57 @@ +/* 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; + } + } |