for (;;) {
    colloc = col;
    if (colloc != 0xff) break;
}
for (i = 0,count = 0; i < 8; i++) {
    row = 1 << i;
    MSDelay(5);
    if (col != 0xff) {
        rowloc = i;
        count++;
    }
}
if (count == 1) {
    // Only one row had a pressed key. Now time to process column values.
    ...
}