XMS Functions
TECH Help! describes all services of the Extended Memory Specification
version 2.0. Version 2.0 has been standard since October, 1992 and is
usually available on 286+ computers running DOS 4.0+.
There are two parts to the XMS API. The first uses INT 2fH 43xxH as a way
to test for installation and to obtain the entry address for the other
services. After obtaining that address, you call it directly. See
INT 2fH 4310H for an example.
See: INT 2fH 4300H (is HIMEM.SYS installed?)
INT 2fH 4310H (get XMM entry address)
AH
▀▀▀ ────────────────────────────────────────────────── General Functions
00H Get XMS version number
────────────────────────────────────────────────────── Standard Functions
01H Request high memory area
02H Release high memory area
03H Global enable A20
04H Global disable A20
05H Local enable A20
06H Local disable A20
07H Query A20 state
──────────────────────────────────────────────────── XMS Memory Functions
08H Query free extended memory
09H Allocate extended memory block
0aH Free extended memory block
0bH Move extended memory block
0cH Lock extended memory block
0dH Unlock extended memory block
0eH Get handle information
0fH Resize extended memory block
─────────────────────────────────────────────────────────── UMB Functions
10H Request upper memory block
11H Release upper memory block
See Also: XMS
XMS Error Codes
Expanded Memory Specification (EMS)
DOS Interrupts
Interrupts and BIOS Services
-♦-