none/tests/amd64/slahf-amd64.c

   1
   2 #include <stdio.h>
   3
   4 typedef unsigned long long int ULong;
   5
   6 extern ULong lahf_1 ( void );
   7 asm("\n"
   8 ".text\n"
   9 "lahf_1:\n"
  10 "\tpushq $0\n"
  11 "\tpopfq\n"
  12 "\tmovabsq $0xFFFFFFFFFFFFFFFF, %rax\n"
  13 "\tmovabsq $0x8765432112345678, %rdx\n"
  14 "\tsubq %rax, %rdx\n"
  15 "\t.byte 0x9F\n" /* lahf */
  16 "\tret\n"
  17 ".previous\n"
  18 );
  19
  20 extern ULong lahf_0 ( void );
  21 asm("\n"
  22 ".text\n"
  23 "lahf_0:\n"
  24 "\tpushq $0\n"
  25 "\tpopfq\n"
  26 "\tmovabsq $0x0, %rax\n"
  27 "\tmovabsq $0x8765432112345678, %rdx\n"
  28 "\tsubq %rax, %rdx\n"
  29 "\t.byte 0x9F\n" /* lahf */
  30 "\tret\n"
  31 ".previous\n"
  32 );
  33
  34 extern ULong sahf_then_lahf ( ULong );
  35 asm("\n"
  36 ".text\n"
  37 "sahf_then_lahf:\n"
  38 "\tmovq %rdi, %rax\n"
  39 "\t.byte 0x9E\n" /* sahf */
  40 "\tmovabsq $0, %rax\n"
  41 "\t.byte 0x9F\n" /* lahf */
  42 "\tret\n"
  43 ".previous\n"
  44 );
  45
  46 int main ( void )
  47 {
  48    ULong i;
  49    printf("0x%llx\n", lahf_0());
  50    printf("0x%llx\n", lahf_1());
  51    for (i = 0; i < 255; i++) {
  52       ULong x = sahf_then_lahf(i << 8);
  53       printf("%llx -> %llx\n", i, x);
  54    }
  55    return 0;
  56 }