none/tests/x86/bt_literal.c

   1
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <assert.h>
   5
   6 typedef unsigned int UInt;
   7
   8 /* Given a word, do bt/bts/btr/btc on bits 0, 1, 2 and 3 of it, and
   9    also reconstruct the original bits 0, 1, 2, 3 by looking at the
  10    carry flag.  Returned result has mashed bits 0-3 at the bottom and
  11    the reconstructed original bits 0-3 as 4-7. */
  12 UInt mash_reg_L ( UInt orig )
  13 {
  14   UInt reconstructed, mashed;
  15   __asm__ __volatile__ (
  16      "movl %2, %%edx\n\t"
  17      ""
  18      "movl $0, %%eax\n\t"
  19      "\n\t"
  20      "btl  $0, %%edx\n\t"
  21      "setb %%cl\n\t"
  22      "movzbl %%cl, %%ecx\n\t"
  23      "orl %%ecx, %%eax\n\t"
  24      "\n\t"
  25      "btsl $1, %%edx\n\t"
  26      "setb %%cl\n\t"
  27      "movzbl %%cl, %%ecx\n\t"
  28      "shll $1, %%ecx\n\t"
  29      "orl %%ecx, %%eax\n\t"
  30      "\n\t"
  31      "btrl $2, %%edx\n\t"
  32      "setb %%cl\n\t"
  33      "movzbl %%cl, %%ecx\n\t"
  34      "shll $2, %%ecx\n\t"
  35      "orl %%ecx, %%eax\n\t"
  36      "\n\t"
  37      "btcl $3, %%edx\n\t"
  38      "setb %%cl\n\t"
  39      "movzbl %%cl, %%ecx\n\t"
  40      "shll $3, %%ecx\n\t"
  41      "orl %%ecx, %%eax\n\t"
  42      "\n\t"
  43      "movl %%eax, %0\n\t"
  44      "movl %%edx, %1"
  45
  46      : "=r" (reconstructed), "=r" (mashed)
  47      : "r" (orig)
  48      : "eax", "ecx", "edx", "cc");
  49   return (mashed & 0xF) | ((reconstructed & 0xF) << 4);
  50 }
  51
  52
  53
  54
  55 UInt mash_mem_L ( int* origp )
  56 {
  57   UInt reconstructed, mashed;
  58   __asm__ __volatile__ (
  59      "movl %2, %%edx\n\t"
  60      ""
  61      "movl $0, %%eax\n\t"
  62      "\n\t"
  63      "btl  $0, (%%edx)\n\t"
  64      "setb %%cl\n\t"
  65      "movzbl %%cl, %%ecx\n\t"
  66      "orl %%ecx, %%eax\n\t"
  67      "\n\t"
  68      "btsl $1, (%%edx)\n\t"
  69      "setb %%cl\n\t"
  70      "movzbl %%cl, %%ecx\n\t"
  71      "shll $1, %%ecx\n\t"
  72      "orl %%ecx, %%eax\n\t"
  73      "\n\t"
  74      "btrl $2, (%%edx)\n\t"
  75      "setb %%cl\n\t"
  76      "movzbl %%cl, %%ecx\n\t"
  77      "shll $2, %%ecx\n\t"
  78      "orl %%ecx, %%eax\n\t"
  79      "\n\t"
  80      "btcl $3, (%%edx)\n\t"
  81      "setb %%cl\n\t"
  82      "movzbl %%cl, %%ecx\n\t"
  83      "shll $3, %%ecx\n\t"
  84      "orl %%ecx, %%eax\n\t"
  85      "\n\t"
  86      "movl %%eax, %0\n\t"
  87      "movl (%%edx), %1"
  88
  89      : "=r" (reconstructed), "=r" (mashed)
  90      : "r" (origp)
  91      : "eax", "ecx", "edx", "cc");
  92   return (mashed & 0xF) | ((reconstructed & 0xF) << 4);
  93 }
  94
  95
  96
  97 UInt mash_reg_W ( UInt orig )
  98 {
  99   UInt reconstructed, mashed;
 100   __asm__ __volatile__ (
 101      "movl %2, %%edx\n\t"
 102      ""
 103      "movl $0, %%eax\n\t"
 104      "\n\t"
 105      "btw  $0, %%dx\n\t"
 106      "setb %%cl\n\t"
 107      "movzbl %%cl, %%ecx\n\t"
 108      "orl %%ecx, %%eax\n\t"
 109      "\n\t"
 110      "btsw $1, %%dx\n\t"
 111      "setb %%cl\n\t"
 112      "movzbl %%cl, %%ecx\n\t"
 113      "shll $1, %%ecx\n\t"
 114      "orl %%ecx, %%eax\n\t"
 115      "\n\t"
 116      "btrw $2, %%dx\n\t"
 117      "setb %%cl\n\t"
 118      "movzbl %%cl, %%ecx\n\t"
 119      "shll $2, %%ecx\n\t"
 120      "orl %%ecx, %%eax\n\t"
 121      "\n\t"
 122      "btcw $3, %%dx\n\t"
 123      "setb %%cl\n\t"
 124      "movzbl %%cl, %%ecx\n\t"
 125      "shll $3, %%ecx\n\t"
 126      "orl %%ecx, %%eax\n\t"
 127      "\n\t"
 128      "movl %%eax, %0\n\t"
 129      "movl %%edx, %1"
 130
 131      : "=r" (reconstructed), "=r" (mashed)
 132      : "r" (orig)
 133      : "eax", "ecx", "edx", "cc");
 134   return (mashed & 0xF) | ((reconstructed & 0xF) << 4);
 135 }
 136
 137
 138
 139
 140 int main ( void )
 141 {
 142   int i, ii;
 143   for (i = 0; i < 0x10; i++) {
 144     ii = i;
 145     printf("0x%x -> 0x%2x 0x%2x 0x%2x\n", i,
 146            mash_reg_L(i), mash_mem_L(&ii), mash_reg_W(i));
 147   }
 148   return 1;
 149 }
 150