tests/tcg/x86_64/cmpxchg.c

   1 #include <assert.h>
   2
   3 static int mem;
   4
   5 static unsigned long test_cmpxchgb(unsigned long orig)
   6 {
   7   unsigned long ret;
   8   mem = orig;
   9   asm("cmpxchgb %b[cmp],%[mem]"
  10       : [ mem ] "+m"(mem), [ rax ] "=a"(ret)
  11       : [ cmp ] "r"(0x77), "a"(orig));
  12   return ret;
  13 }
  14
  15 static unsigned long test_cmpxchgw(unsigned long orig)
  16 {
  17   unsigned long ret;
  18   mem = orig;
  19   asm("cmpxchgw %w[cmp],%[mem]"
  20       : [ mem ] "+m"(mem), [ rax ] "=a"(ret)
  21       : [ cmp ] "r"(0x7777), "a"(orig));
  22   return ret;
  23 }
  24
  25 static unsigned long test_cmpxchgl(unsigned long orig)
  26 {
  27   unsigned long ret;
  28   mem = orig;
  29   asm("cmpxchgl %[cmp],%[mem]"
  30       : [ mem ] "+m"(mem), [ rax ] "=a"(ret)
  31       : [ cmp ] "r"(0x77777777u), "a"(orig));
  32   return ret;
  33 }
  34
  35 int main()
  36 {
  37   unsigned long test = 0xdeadbeef12345678ull;
  38   assert(test == test_cmpxchgb(test));
  39   assert(test == test_cmpxchgw(test));
  40   assert(test == test_cmpxchgl(test));
  41   return 0;
  42 }