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.

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

2021/08/05 12:15 · prokushev

Int 31H, AH=0BH, AL=02H




Get State of Debug Watchpoint


AX = 0B02H
BX = watchpoint handle


if function successful
Carry flag = clear
AX = watchpoint status
Bit Significance
0 0 = watchpoint has not been encountered 1 = watchpoint has been encountered
1-15 reserved


Returns the state of a debug watchpoint that was previously set using the Set Debug Watchpoint function (Int 31H Function 0B00H).

The client can use Int 31H Function 0B03H to clear the watchpoint state without releasing the watchpoint handle.

See also


Process manager INT 2FH 1680H, 1687H
Memory manager
Misc INT 2FH 1686H, 168AH
2021/08/13 16:23 · prokushev

en/docs/dpmi/api/int31/0b/02.txt · Last modified: 2021/08/27 08:29 by prokushev