ack/modules/src/flt_arith/b64_sft.c
1989-10-16 17:56:36 +00:00

48 lines
996 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".
*/
/* $Header$ */
#include "misc.h"
flt_b64_sft(e,n)
register struct flt_mantissa *e;
register int n;
{
if (n > 63 || n < -63) {
e->flt_l_32 = 0;
e->flt_h_32 = 0;
return;
}
if (n >= 32) {
e->flt_l_32 = e->flt_h_32;
e->flt_h_32 = 0;
n -= 32;
}
if (n > 0) {
e->flt_l_32 = (e->flt_l_32 >> 1) & 0x7FFFFFFF;
e->flt_l_32 >>= (n - 1);
if (e->flt_h_32 != 0) {
e->flt_l_32 |= (e->flt_h_32 << (32 - n)) & 0xFFFFFFFF;
e->flt_h_32 = (e->flt_h_32 >> 1) & 0x7FFFFFFF;
e->flt_h_32 >>= (n - 1);
}
}
n = -n;
if (n >= 32) {
e->flt_h_32 = e->flt_l_32;
e->flt_l_32 = 0;
n -= 32;
}
if (n > 0) {
e->flt_h_32 = (e->flt_h_32 << n) & 0xFFFFFFFF;
if (e->flt_l_32 != 0) {
long l = (e->flt_l_32 >> 1) & 0x7FFFFFFF;
e->flt_h_32 |= (l >> (31 - n));
e->flt_l_32 = (e->flt_l_32 << n) & 0xFFFFFFFF;
}
}
}