source: trunk/minix/lib/ack/fphook/shifter.fc@ 20

/*
  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
  See the copyright notice in the ACK home directory, in the file "Copyright".
*/

/* $Header: /cvsup/minix/src/lib/ack/fphook/shifter.fc,v 1.1 2005/10/10 15:27:44 beng Exp $ */

# 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;
}