ack/mach/proto/fp/sft_ext.c
1988-07-25 10:46:15 +00:00

61 lines
916 B
C

/*
(c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
See the copyright notice in the ACK home directory, in the file "Copyright".
*/
/* $Header$ */
/*
SHIFT TWO EXTENDED NUMBERS INTO PROPER
ALIGNMENT FOR ADDITION (exponents are equal)
*/
#include "FP_types.h"
sft_ext(e1,e2)
EXTEND *e1,*e2;
{
register EXTEND *s;
register int diff;
long tmp;
diff = e1->exp - e2->exp;
if (!diff)
return; /* exponents are equal */
if (diff < 0) { /* e2 is larger */
/* shift e1 */
diff = -diff;
s = e1;
}
else /* e1 is larger */
/* shift e2 */
s = e2;
s->exp += diff;
if (diff > 63) { /* no relative value */
s->m1 = 0L;
s->m2 = 0L;
return;
}
if (diff > 32) {
diff -= 32;
s->m2 = s->m1;
s->m1 = 0L;
}
if (diff) {
if (s->m1) {
tmp = s->m1;
tmp <<= (32-diff);
s->m1 >>= diff;
}
else
tmp = 0L;
s->m2 >>= diff;
s->m2 |= tmp;
}
}