getsign

getsign.c

int getsign (register int x) {
        register int z;
        /* it would be nice not to have to clobber the input, but isel doesn't like r0  */
        asm (
                "cmpi 0, 0, %2, 0\n"
                "addi %2, 0, -1\n"
                "isel %0, %2, %0, 0\n" // lt
                "addi %2, 0, 1\n"
                "isel %0, %2, %0, 1\n" // gt
                "addi %2, 0, 0\n"
                "isel %0, %2, %0, 2\n" // eq
                : "=r"(z), "=r"(x) // output
                : "r"(x) // inputs
                : "cr0", "r0"
        );
        return z;
}