Int 21/AX=4402h/SF=00h

Memory Managers - GET API ENTRY POINT

AX = 4402h subfn 00h
BX = file handle for device "EMMXXXX0"
CX = 0006h (size of buffer in bytes)
DS:DX -> buffer for API entry point record (see #01512)
first byte must be 00h on entry

Return:
CF clear if successful
buffer filled (see #03603 at INT 67/AH=3Fh)
CF set on error
AX = error code (01h,05h,06h,0Dh) (see #01680 at AH=59h/BX=0000h)

Notes: This function is supported by Microsoft EMM386.EXE v4.45+ and CEMM v5.10+, and is intended for use by MS Windows as it starts up. If no other program has hooked INT 67, an alternate installation check for CEMM is testing for the string "COMPAQ EXPANDED MEMORY MANAGER 386" at offset 14h in the INT 67 handler's segment; if present, the word at offset 12h contains the offset of the API entry point


Format of memory manager API entry point record:

Offset  Size    Description     (Table 01512)
00h    WORD    ??? (0022h for CEMM 5.11, 0025h for MS EMM386 v4.45)
02h    DWORD   manager's private API entry point
(see #01513,#03666 at INT 67/AX=FFA5h)


(Table 01513)
Call CEMM v5.10+ entry point with:.
AH = 00h get memory manager's state
Return:
AH = state
bit 0:
Turned OFF
bit 1:
AUTO mode enabled.
AH = 01h set memory manager's state
AL = new state (00h ON, 01h OFF, 02h AUTO)
Return:
CF clear if successful
CF set on error.
AH = 02h Weitek coprocessor support
AL = subfunction
00h get Weitek support state
Return:
AL = status
bit 0:
Weitek coprocessor is present
bit 1:
Weitek support is enabled
01h turn on Weitek support
02h turn off Weitek support
Return:
CF clear if successful
CF set on error
AH = error code (01h invalid subfunc, 02h no Weitek).
AH = 05h get statistics
???.
AH > 06h
Return:
CF set
AH = 01h (invalid function)

Notes: AH=03h,04h,06h are NOPs which return CF clear, presumably for backwards compatibility with earlier versions of CEMM. In v5.11, AH=05h merely prints an error message (using INT 21/AH=09h) stating that a different version of CEMM is installed and it is therefore not possible to display the statistics

Category: Memory Management - Int 21h - M

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