Note: This API calls are shared between DOS and Win16 personality.

DPMI is a shared interface for DOS applications to access Intel 80286+ CPUs services. DOS DMPI host provides core services for protected mode applications. Multitasking OS with DOS support also provides DMPI in most cases. Windows standard and extended mode kernel is a DPMI client app. Standard and extended mode kernel differs minimally and shares common codebase. Standard Windows kernel works under DOSX extender. DOSX is a specialized version of 16-bit DPMI Extender (but it is standard DPMI host). Standard mode is just DPMI client, exnhanced mode is DPMI client running under Virtual Machime Manager (really, multitasker which allow to run many DOS sessions). Both modes shares DPMI interface for kernel communication. The OS/2 virtual DOS Protected Mode Interface (VDPMI) device driver provides Version 0.9 DPMI support for virtual DOS machines. Win16 (up to Windows ME) provides Version 0.9 DPMI support. Windows in Standard Mode provides DPMI services only for Windows Applications, not DOS sessions.

DPMI host often merged with DPMI extender. Usually DPMI extender provide DPMI host standard services and DOS translation or True DPMI services.

Int 31H, AH=00H, AL=07H

Version

0.9

Brief

Set Segment Base Address

Input

AX = 0007H
BX = selector
CX:DX = 32-bit linear base address of segment

Return

if function successful
Carry flag = clear
if function unsuccessful
Carry flag = set
AX = error code
8022H	invalid selector
8025H	invalid linear address (changing the base would cause the descriptor to reference a linear address range outside that allowed for DPMI clients)

Notes

Sets the 32-bit linear base address field in the LDT descriptor for the specified segment.

A DPMI 1.0 host will automatically reload any segment register which contains the selector specified in register BX. It is suggested that DPMI 0.9 hosts also implement this.

Refer to the rules for descriptor usage in Appendix D.

See also

Note

Text based on http://www.delorie.com/djgpp/doc/dpmi/

DPMI
Process manager	INT 2FH 1680H, 1687H
Signals
Memory manager
Misc	INT 2FH 1686H, 168AH
Devices