Int 67H [EMS 4.0] Function 5BH (91) Subfunction 04H Deallocate alternate map register set

Releases an alternate map register set that was previously allocated with Int 67H Function 5BH Subfunction 03H.

Call with:

AH = 5BH

AL = 04H

BL = alternate register set number

Returns:

If function successful

AH = 00H

If function unsuccessful

AH = error code

Notes:

The current alternate map register set cannot be deallocated.

This function is intended for use by operating systems only and can be disabled by the operating system at any time.