minix/lib/float/shifter.c
2005-04-21 14:53:53 +00:00

75 lines
1.1 KiB
C
Executable file

/*
(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 "FP_types.h"
void
b64_sft(e1,n)
B64 *e1;
int n;
{
if (n > 0) {
if (n > 63) {
e1->l_32 = 0;
e1->h_32 = 0;
return;
}
if (n >= 32) {
e1->l_32 = e1->h_32;
e1->h_32 = 0;
n -= 32;
}
if (n > 0) {
e1->l_32 >>= n;
if (e1->h_32 != 0) {
e1->l_32 |= (e1->h_32 << (32 - n));
e1->h_32 >>= n;
}
}
return;
}
n = -n;
if (n > 0) {
if (n > 63) {
e1->l_32 = 0;
e1->h_32 = 0;
return;
}
if (n >= 32) {
e1->h_32 = e1->l_32;
e1->l_32 = 0;
n -= 32;
}
if (n > 0) {
e1->h_32 <<= n;
if (e1->l_32 != 0) {
e1->h_32 |= (e1->l_32 >> (32 - n));
e1->l_32 <<= n;
}
}
}
}
void
b64_lsft(e1)
B64 *e1;
{
/* shift left 1 bit */
e1->h_32 <<= 1;
if (e1->l_32 & 0x80000000L) e1->h_32 |= 1;
e1->l_32 <<= 1;
}
void
b64_rsft(e1)
B64 *e1;
{
/* shift right 1 bit */
e1->l_32 >>= 1;
if (e1->h_32 & 1) e1->l_32 |= 0x80000000L;
e1->h_32 >>= 1;
}