Int 2F/AX=12FFh/BX=0006h

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DR DOS 6+, Novell DOS 7+ - EMM386.EXE - VIDEO MEMORY SPACE CONTROL

AX = 12FFh
BX = 0006h
DX = 0000h
CX = function
0000h get status of video memory space (MEMMAX /V)
0001h map memory into video memory space (MEMMAX +V)
0002h unmap memory from video memory space (MEMMAX -V)

Return:
CF clear if successful AX = 0000h (successful) BX = segment of reserved video RAM CX = segment of used video RAM DX = segment of first upper MCB

Notes: This functionality is provided by EMM386, and partially supported by HIDOS.SYS. BL specifies which program handles the call, BH is the function number

BUG: 4DOS 5.51(a) often hangs the system (reported to be reproducable), if MEMMAX +V is issued from the 4DOS prompt. To avoid this, one should temporary load COMMAND.COM followed by MEMMAX +v , starting the application, MEMMAX -v and EXIT. 4DOS 5.5c does not show this phenomena on the same systems where 5.51a hangs.

See Also: AX=D201h/BX=4849h

(Table 04105) Values for DR DOS memory space control error code: 00h successful 80h video memory already unmapped 81h video memory already mapped 82h no video memory reserved (/VIDEO not specified) 83h video memory in use (graphics mode or non-standard text mode) 84h mapped video memory contains allocated arena(s) 85h hardware error 86h driver requires protected mode but is permanently in real mode ("EMM386 OFF")

Category: Memory Management - Int 2Fh - D

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