none/tests/amd64/lzcnt64.c

   1
   2 #include <stdio.h>
   3
   4 typedef  unsigned long long int  ULong;
   5 typedef  unsigned int            UInt;
   6
   7 __attribute__((noinline))
   8 void do_lzcnt64 ( /*OUT*/UInt* flags, /*OUT*/ULong* res, ULong arg )
   9 {
  10   ULong block[3] = { arg, 0ULL, 0ULL };
  11   __asm__ __volatile__(
  12     "movabsq $0x5555555555555555, %%r11" "\n\t"
  13     "lzcntq 0(%0), %%r11"     "\n\t"
  14     "movq %%r11, 8(%0)"       "\n\t"
  15     "pushfq"                  "\n\t"
  16     "popq %%r11"              "\n\t"
  17     "movq %%r11, 16(%0)"      "\n"
  18     : : "r"(&block[0]) : "r11","cc","memory"
  19   );
  20   *res = block[1];
  21   *flags = block[2] & 0x8d5;
  22 }
  23
  24 __attribute__((noinline))
  25 void do_lzcnt32 ( /*OUT*/UInt* flags, /*OUT*/ULong* res, ULong arg )
  26 {
  27   ULong block[3] = { arg, 0ULL, 0ULL };
  28   __asm__ __volatile__(
  29     "movabsq $0x5555555555555555, %%r11" "\n\t"
  30     "lzcntl 0(%0), %%r11d"    "\n\t"
  31     "movq %%r11, 8(%0)"       "\n\t"
  32     "pushfq"                  "\n\t"
  33     "popq %%r11"              "\n\t"
  34     "movq %%r11, 16(%0)"      "\n"
  35     : : "r"(&block[0]) : "r11","cc","memory"
  36   );
  37   *res = block[1];
  38   *flags = block[2] & 0x8d5;
  39 }
  40
  41 __attribute__((noinline))
  42 void do_lzcnt16 ( /*OUT*/UInt* flags, /*OUT*/ULong* res, ULong arg )
  43 {
  44   ULong block[3] = { arg, 0ULL, 0ULL };
  45   __asm__ __volatile__(
  46     "movabsq $0x5555555555555555, %%r11" "\n\t"
  47     "lzcntw 0(%0), %%r11w"    "\n\t"
  48     "movq %%r11, 8(%0)"       "\n\t"
  49     "pushfq"                  "\n\t"
  50     "popq %%r11"              "\n\t"
  51     "movq %%r11, 16(%0)"      "\n"
  52     : : "r"(&block[0]) : "r11","cc","memory"
  53   );
  54   *res = block[1];
  55   *flags = block[2] & 0x8d5;
  56 }
  57
  58 int main ( void )
  59 {
  60    ULong w;
  61
  62    w = 0xFEDC192837475675ULL;
  63    while (1) {
  64       ULong res;
  65       UInt  flags;
  66       do_lzcnt64(&flags, &res, w);
  67       printf("lzcntq %016llx -> %016llx %04x\n", w, res, flags);
  68       if (w == 0) break;
  69       w = ((w >> 2) | (w >> 1)) + (w / 17ULL);
  70    }
  71
  72    w = 0xFEDC192837475675ULL;
  73    while (1) {
  74       ULong res;
  75       UInt  flags;
  76       do_lzcnt32(&flags, &res, w);
  77       printf("lzcntl %016llx -> %016llx %04x\n", w, res, flags);
  78       if (w == 0) break;
  79       w = ((w >> 2) | (w >> 1)) + (w / 17ULL);
  80    }
  81
  82    w = 0xFEDC192837475675ULL;
  83    while (1) {
  84       ULong res;
  85       UInt  flags;
  86       do_lzcnt16(&flags, &res, w);
  87       printf("lzcntw %016llx -> %016llx %04x\n", w, res, flags);
  88       if (w == 0) break;
  89       w = ((w >> 2) | (w >> 1)) + (w / 17ULL);
  90    }
  91
  92    return 0;
  93 }