Parameter-Related Errors

Parameter-related errors do not return an error indication. The Int 17h BIOS services check the following parameter-related conditions:

The function# (in AH) is in the range (0-2).

The port# (in DX) is in the range (0-3) (only port 0 is implemented in the HP palmtop).

The corresponding base I/O address (EIADRTBL RAM) is non-zero.

If the input parameters are invalid (one or more of the above conditions are not true), the requested service is not performed, and all CPU registers are returned intact.

If the input parameters are valid (above conditions all true), the service will be executed. All services exit through service 02h, hence return status information to the caller.