| 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 | } |