INT 13 calls return a status value via %ah, with CF set if %ah is
non-zero (indicating an error). Our wrappers zero the whole of %ax if
CF is clear, to allow C code (which has no easy access to CF) to
simply test for a non-zero status to detect an error.
The current code assigns the returned status to a uint8_t, effectively
testing %al rather than %ah. Fix by treating the returned status as a
uint16_t instead.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
f8cf3ceb0b