| void __attribute__((naked)) cas(int *a, int *b) { |
| // This atomic sequence implements a copy-and-swap function. This test should |
| // at the first instruction, and after step instruction, we should stop at the |
| // end of the sequence (on the ret instruction). |
| asm volatile("1:\n\t" |
| "lr.w a2, (a0)\n\t" |
| "and a5, a2, a4\n\t" |
| "beq a5, a1, 2f\n\t" |
| "xor a5, a2, a0\n\t" |
| "and a5, a5, a4\n\t" |
| "xor a5, a2, a5\n\t" |
| "sc.w a5, a1, (a3)\n\t" |
| "beqz a5, 1b\n\t" |
| "2:\n\t" |
| "ret\n\t"); |
| } |
| |
| int main() { |
| int a = 4; |
| int b = 2; |
| cas(&a, &b); |
| } |