Int 31H Function 0100H

Allocate DOS Memory Block [0.9]

Allocates a block of memory from the DOS memory pool, i.e. memory below the 1 MB boundary that is controlled by DOS. Such memory blocks are typically used to exchange data with real mode programs, TSRs, or device drivers. The function returns both the real mode segment base address of the block and one or more descriptors that can be used by protected mode applications to access the block.

Call With

AX = 0100H
BX = number of (16-byte) paragraphs desired


if function successful
Carry flag = clear
AX = real mode segment base address of allocated block
DX = selector for allocated block

if function unsuccessful
Carry flag = set
AX = error code
0007Hmemory control blocks damaged (also returned by DPMI 0.9 hosts)
0008Hinsufficient memory (also returned by DPMI 0.9 hosts).
8011Hdescriptor unavailable
BX = size of largest available block in paragraphs


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