Int 21/AX=4402h/SF=01h

Memory Managers - GET EMM IMPORT STRUCTURE ADDRESS

AX = 4402h subfn 01h
BX = file handle for device "EMMXXXX0"
CX = 0006h (size of buffer in bytes)
DS:DX -> buffer for EMM import structure record (see #01514)
first byte must be 01h on entry

Return:
CF clear if successful
buffer filled (see also #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+, QEMM-386 v6+, and CEMM v5.10+, and is intended for use by MS Windows as it starts up. For QEMM-386, this call always returns an error if Windows3 support has been disabled with the NW3 switch

See Also: INT 67/AH=3Fh


Format of EMM import structure record:

Offset  Size    Description     (Table 01514)
00h    DWORD   physical address of EMM import structure (see #01515)
04h    BYTE    EMM import structure major version
05h    BYTE    EMM import structure minor version

Note: Vession 1.00 contains only EMS information (Windows 3.0+). Version 1.10 contains UMB/XMS/HMA/EMS information (Windows 3.1). Version 1.11 is version 1.10 plus memory manager maker/product name

See Also: #03643

Format of Global EMM Import record: Offset Size Description (Table 01515) 00h BYTE bit flags

bit 2:
???

bit 3:
Free EMM386 virtual HMA only if hma_page_table_paddr!=0

bit 4:
No UMB??? 01h BYTE reserved (0) 02h WORD size of structure in bytes 04h WORD structure version 06h DWORD reserved 0Ah 384 BYTEs 64 EMS frame status records (see #01516), one per 16K of real-mode 1M address space 18Ah BYTE ??? (must be at least 3*number_of_EMS_frames+4) 18Bh BYTE number of UMB frame descriptors following 18Ch 4N DWORDs UMB frame descriptors each is 4 DWORDs giving physical page numbers for the four 4K pages of a 16K EMS frame (00000000h if non-UMB page) var BYTE number of EMS handle info records following 16N BYTEs EMS handle info records (see #01518) ---version 1.10+ ---. DWORD realmode INT 67 vector (used by Windows to set breakpoints). DWORD physical address of HMA page table values. BYTE number of free page entries following 2N DWORDs free page entries each is: DWORD physical page number DWORD number of consecutive physical pages. BYTE number of XMS handle info records following 00h if memory manager does not emulate XMS or has real mode XMS code which can execute in the Windows environment 12N BYTEs XMS handle info records (see #01519). BYTE number of free UMB info records following 2N WORDs free UMB info records each is: WORD real mode start segment WORD size in paragraphs ---version 1.11--- 20 BYTEs blank-padded maker name 20 BYTEs blank-padded product name

Format of EMS frame status record: Offset Size Description (Table 01516) 00h BYTE frame type (see #01517) 01h BYTE owner handle (00h/FFh = none) from frame including UMB index to UMB frame descriptors 02h WORD logical page for frame, 7FFFh if none, FFFFh if non-EMS frame 04h BYTE EMS physical page number (FFh for non-EMS = don't care???) 05h BYTE flags for non-EMS frames (00h for EMS frame) bits 0,1 for first 4K, bits 2,3 for second 4K, etc:

10:
Direct mapping (linear address = physical address)

01:
UMB mapping

Bitfields for EMS frame type: Bit(s) Description (Table 01517) 0 EMS frame 1 (if EMS frame) in standard 64K page frame 2 first 4K of frame is UMB 3 second 4K of frame is UMB 4 third 4K of frame is UMB 5 last 4K of frame is UMB

Format of EMS handle info record: Offset Size Description (Table 01518) 00h BYTE handle number (00h = system handle) 01h BYTE flags

bit 0:
Normal handle rather than system handle

bit 2:
??? (set by some EMS managers) 02h 8 BYTEs EMS handle's name 0Ah WORD number of 16K pages for handle 0Ch DWORD physical address of page table entries forming page map

Note: All values should be zero for the system handle if no large frame support is present


Format of XMS handle info record:

Offset  Size    Description     (Table 01519)
00h    WORD    handle
02h    WORD    flags
bit 0:
Handle usable by Windows
(already in use when Windows started if clear)
bit 1:
Reserved (0)
04h    DWORD   size in KB (may be zero, used only if flags bit 0 set)
08h    DWORD   physical address (only if flags bit 0 set)

Category: Memory Management - Int 21h - M

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