blob: 35e8aee2cae4b739ce309604a3f9f3da12a9f4bc [file] [log] [blame] [edit]
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);
}