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=02H, AL=13H

Version

1.0

Brief

Set Extended Processor Exception Handler Vector (Real Mode)

Input

AX = 0213H
BL = exception/fault number (00H-1FH)
CX:(E)DX = selector:offset of exception handler

Return

if function successful
Carry flag = clear
if function unsuccessful
Carry flag = set
AX = error code
8021H	invalid value (BL not in range 00H-1FH)
8022H	invalid selector

Notes

CX:(E)DX does not specify a real-mode segment:offset. The reason is that this function allows a client to set the address of an exception handler which will receive control in protected mode when the specified exception occurs in real mode (i.e. the host will provide an implied mode switch for the purposes of servicing the exception, then return to real mode after the handler exits).

Real mode exceptions are sent to the primary client of the virtual machine. (See Appendix A: Glossary for definition of primary client.)

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