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=04H, AL=00H
Version
0.9
Brief
Get Version
Input
AX = 0400H
Return
Carry flag = clear (this function always succeeds) AH = DPMI major version as a binary number AL = DPMI minor version as a binary number BX = flags
| Bits | Significance |
|---|---|
| 0 | 0 = host is 16-bit DPMI implementation 1 = host is 32-bit (80386) DPMI implementation |
| 1 | 0 = CPU returned to Virtual 86 mode for reflected interrupts 1 = CPU returned to real mode for reflected interrupts |
| 2 | 0 = virtual memory not supported 1 = virtual memory supported |
| 3 | reserved, for historical reasons |
| 4-15 | reserved for later use |
CL = processor type
| Value | Significance |
|---|---|
| 02H | 80286 |
| 03H | 80386 |
| 04H | 80486 |
| 05H-FFH | reserved for future Intel processors |
DH = current value of virtual master PIC base interrupt DL = current value of virtual slave PIC base interrupt
Notes
Returns the version number of the DPMI Specification implemented by the DPMI host. Clients can use this information to determine which function calls are supported in the current environment.
Under DPMI hosts, the major version number is returned in AH and the minor version number is returned in AL. There are two decimal digits for the minor version number with the least-significant digit representing the revision number of the minor version number. Under DPMI version 0.9 hosts, AH is returned as 0, and AL is returned as decimal 90 (5AH). In hypothetical DPMI version 2.3, AH would be returned as 2 and AL would be returned as 30 (1EH).
See also
Note
Text based on http://www.delorie.com/djgpp/doc/dpmi/