Int 21/AX=4402h

HIGHUMM.SYS v1.17+ - IOCTL - GET API ADDRESS

AX = 4402h
BX = handle for device "KSP$UMM"
CX = 0004h
DS:DX -> DWORD to hold entry point (see #01446)

Return:
CF set on error
AX = error code (see #01680 at AH=59h/BX=0000h)
CF clear if successful
AX = number of bytes read

Program: HIGHUMM.SYS is part of the shareware "The Last Byte" memory management package by Key Software Products

See Also: AX=4402h"LASTBYTE"



(Table 01446)
Call HIGHUMM.SYS entry point with:.
AH = 00h allocate UMB (same as XMS function 10h) (see INT 2F/AX=4310h)
DX = size in paragraphs
Return:
BX = segment number (if successful)
DX = size of requested block/size of largest block.
AH = 01h deallocate UMB (same as XMS func 11h) (see INT 2F/AX=4310h)
DX = segment number of UMB.
AH = 02h request a bank-switched memory block
DX = size in paragraphs
Return:
BX = segment number (if successful)
DX = size of requested block/size of largest block.
AH = 03h release a bank-switched memory block
DX = segment number.
AH = 04h transfer data to/from high memory
DS:SI -> source
ES:DI -> destination
CX = length in bytes

Note: Enables bank-switched memory, does the copy, then disables bank-switched memory. AH = 05h get a word from bank-switched memory ES:DI -> word to read

Return:
DX = word.
AH = 06h put a word to bank-switched memory
ES:DI -> word to write
DX = word.
AH = 07h put a byte to bank-switched memory
ES:DI -> byte to write
DL = byte.
AH = 08h enable bank-switched memory
DS:SI -> 6-byte status save area.
AH = 09h disable bank-switched memory
DS:SI -> 6-byte save area from enable call (AH=08h).
AH = 0Ah assign name to UMB or high bank-switched block
DX = segment number
DS:SI -> 8-byte blank-padded name.
AH = 0Bh locate UMB block by name
DS:SI -> 8-byte blank-padded name
Return:
BX = segment number (if successful)
DX = size of block.
AH = 0Ch locate bank-switched block by name
DS:SI -> 8-byte blank-padded name
Return:
BX = segment number (if successful)
DX = size of block

Return:
AX = status code
0001h successful
0000h failed
BL = error code
80h not implemented
B0h insufficient memory, smaller block available
B1h insufficient memory, no blocks available
B2h invalid segment number

Note: Only functions 00h and 01h are always available; the remaining functions are only enabled if the proper commandline switch is given

Category: Memory Management - Int 21h - H

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