lib/ack/fphook/shifter.fc

   1 /*
   2   (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
   3   See the copyright notice in the ACK home directory, in the file "Copyright".
   4 */
   5
   6 /* $Header$ */
   7
   8 # include "FP_types.h"
   9
  10 void
  11 b64_sft(e1,n)
  12 B64     *e1;
  13 int     n;
  14 {
  15         if (n > 0) {
  16                 if (n > 63) {
  17                         e1->l_32 = 0;
  18                         e1->h_32 = 0;
  19                         return;
  20                 }
  21                 if (n >= 32) {
  22                         e1->l_32 = e1->h_32;
  23                         e1->h_32 = 0;
  24                         n -= 32;
  25                 }
  26                 if (n > 0) {
  27                         e1->l_32 >>= n;
  28                         if (e1->h_32 != 0) {
  29                                 e1->l_32 |= (e1->h_32 << (32 - n));
  30                                 e1->h_32 >>= n;
  31                         }
  32                 }
  33                 return;
  34         }
  35         n = -n;
  36         if (n > 0) {
  37                 if (n > 63) {
  38                         e1->l_32 = 0;
  39                         e1->h_32 = 0;
  40                         return;
  41                 }
  42                 if (n >= 32) {
  43                         e1->h_32 = e1->l_32;
  44                         e1->l_32 = 0;
  45                         n -= 32;
  46                 }
  47                 if (n > 0) {
  48                         e1->h_32 <<= n;
  49                         if (e1->l_32 != 0) {
  50                                 e1->h_32 |= (e1->l_32 >> (32 - n));
  51                                 e1->l_32 <<= n;
  52                         }
  53                 }
  54         }
  55 }
  56
  57 void
  58 b64_lsft(e1)
  59 B64     *e1;
  60 {
  61         /*      shift left 1 bit */
  62         e1->h_32 <<= 1;
  63         if (e1->l_32 & 0x80000000L) e1->h_32 |= 1;
  64         e1->l_32 <<= 1;
  65 }
  66
  67 void
  68 b64_rsft(e1)
  69 B64     *e1;
  70 {
  71         /*      shift right 1 bit */
  72         e1->l_32 >>= 1;
  73         if (e1->h_32 & 1) e1->l_32 |= 0x80000000L;
  74         e1->h_32 >>= 1;
  75 }