ack/mach/mips/top/table

/* MIPS table for ACK target optimizer */

MAXOP 5;
LABEL_STARTER '.';

%%;

X, Y, Z                      { TRUE };
R                            { TRUE };

%%;

/* Whitespace is significant here! */

addiu R, R, X : addiu R, R, Y { plus(X, Y, Z) } -> addiu R, R, Z ;

addiu X, X, 0                -> ;

b X : nop : labdef X         -> labdef X ;

%%;

/* Does it fit a signed 16-bit integer? */
static int fits16(long l) {
        return l >= -32768 && l <= 32767;
}

/* Tries sum = a + b with signed 16-bit integers. */
int plus(const char *a, const char *b, const char *sum)
{
        long la, lb, lsum;
        char *end;

        la = strtol(a, &end, 10);
        if (*a == '\0' || *end != '\0' || !fits16(la))
                return 0;
        lb = strtol(b, &end, 10);
        if (*b == '\0' || *end != '\0' || !fits16(lb))
                return 0;

        lsum = la + lb;
        if (!fits16(lsum))
                return 0;
        snprintf(sum, 7, "%ld", lsum);
        return 1;
}