Parameter-Related Errors

Parameter related errors do not return an error indication. The Int 14h BIOS services checks the following parameter-related conditions when it receives input:

The function# (AH) is in the range (0-3).

The port# (DX) is in the range (0-3).

The port# (DX) exists in hardware (Base I/O Address in EIADRTBL RAM).

If any of the conditions above are not true, the requested service is not performed, and all CPU registers are returned intact.