Int 67H [EMS 4.0] Function 5BH (91) Subfunction 03H Allocate alternate map register set

Allocates an alternate map register set for use with Int 67H Function 5BH Subfunctions 00H and 01H. The contents of the currently active map registers are copied into the newly allocated alternate map registers in order to provide an initial context when they are selected.

Call with:

AH = 5BH

AL = 03H

Returns:

If function successful

AH = 00H

BL = alternate map register set number or zero, if no alternate

sets are available

If function unsuccessful

AH = error code

Note:

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