; $Id$

;; @file

; IPRT - DevHelp_GetDOSVar, Ring-0 Driver, OS/2.

;

;

; Copyright (c) 1999-2007 knut st. osmundsen <bird-src-spam@anduin.net>

;

; Permission is hereby granted, free of charge, to any person

; obtaining a copy of this software and associated documentation

; files (the "Software"), to deal in the Software without

; restriction, including without limitation the rights to use,

; copy, modify, merge, publish, distribute, sublicense, and/or sell

; copies of the Software, and to permit persons to whom the

; Software is furnished to do so, subject to the following

; conditions:

;

; The above copyright notice and this permission notice shall be

; included in all copies or substantial portions of the Software.

;

; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES

; OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

; NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

; HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,

; WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

; FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

; OTHER DEALINGS IN THE SOFTWARE.

;

;*******************************************************************************

;* Header Files *

;*******************************************************************************

%define RT_INCL_16BIT_SEGMENTS

%include "iprt/asmdefs.mac"

%include "iprt/err.mac"

;*******************************************************************************

;* External Symbols *

;*******************************************************************************

extern KernThunkStackTo32

extern KernThunkStackTo16

extern NAME(g_fpfnDevHlp)

;*******************************************************************************

;* Defined Constants And Macros *

;*******************************************************************************

%define DevHlp_GetDOSVar 24h

BEGINCODE

;

; Jump table used by RTR0Os2DHQueryDOSVar

;

DosVarJumpTab:

dd 0 ; 0 - Reserved

dd Load1600 ; 1 - GIS

dd Load1616 ; 2 - LIS

dd 0 ; 3 - Reserved

dd Load1616 ; 4 - VectorSDF

dd Load1616 ; 5 - VectorReboot

dd Load1616 ; 6 - VectorMSATS

dd AsIs ; 7 - YieldFlag (Resched)

dd AsIs ; 8 - TCYieldFlag (TCResched)

dd AsIs ; 9 - DOSTable

dd Load1616 ; a - VectorDEKKO

dd AsIs ; b - CodePgBuff

dd Load1616 ; c - VectorRIPL

dd AsIs ; d - InterruptLevel

dd AsIs ; e - DevClassTables

dd AsIs ; f - DMQS_Sel

dd AsIs ;10 - APMInfo

dd LoadWord ;11 - APM_Length (length of above structure)

DosVarJumpTabEnd:

%define DosVarJumpTabSize (DosVarJumpTabEnd - DosVarJumpTab) / 4

;;

; Unified DevHelp_GetDOSVar -> Far 16:16 pointer wrapper.

;

; @param iVar [ebp + 08h] Variable.

; @param iMember [ebp + 0ch] Member.

; @param pfp [ebp + 10h] Where to store the variable address (pointer to 16:16).

;

BEGINPROC_EXPORTED RTR0Os2DHQueryDOSVar

; switch stack first.

call KernThunkStackTo16

; normal prolog.

push ebp

mov ebp, esp

push dword [NAME(g_fpfnDevHlp)] ; ebp - 4

push ebx ; save ebx

push es ; save es

; setup the devhelp call and switch to

mov eax, [ebp + 08h] ; iVar (8-bit)

mov ecx, [ebp + 0ch] ; iMember (16-bit)

mov dl, DevHlp_GetDOSVar

; jump to the 16-bit code.

;jmp far dword NAME(RTR0Os2DHQueryDOSVar_16) wrt CODE16

db 066h

db 0eah

dw NAME(RTR0Os2DHQueryDOSVar_16) wrt CODE16

dw CODE16

BEGINCODE16

GLOBALNAME RTR0Os2DHQueryDOSVar_16

call far [ss:ebp - 4]

;jmp far dword NAME(RTR0Os2DHQueryDOSVar) wrt FLAT

db 066h

db 0eah

dd NAME(RTR0Os2DHQueryDOSVar_32) ;wrt FLAT

dw TEXT32 wrt FLAT

BEGINCODE

GLOBALNAME RTR0Os2DHQueryDOSVar_32

jc Error1

;

; Make ax:ebx contain the pointer and take action according

; to the variable jump table.

;

and ebx, 0000ffffh ; clean high part of ebx

movzx ecx, byte [ebp + 08] ; iVar

cmp ecx, DosVarJumpTabSize

jg Error2

jmp [DosVarJumpTab + ecx * 4]

; Load Word at ax:ebx.

LoadWord:

mov es, ax

movzx edx, word [es:ebx]

jmp StoreIt

; Load selector at ax:ebx.

Load1600:

mov es, ax

movzx edx, word [es:ebx]

shl edx, 16

jmp StoreIt

; Load 16:16 ptr at ax:ebx.

Load1616:

mov es, ax

mov edx, dword [es:ebx]

jmp StoreIt

; Move ax:bx into edx.

AsIs:

mov dx, ax

shl edx, 16

mov dx, bx

jmp StoreIt

Error2:

mov eax, VERR_INVALID_PARAMETER

jmp Done

Error1:

mov eax, VERR_GENERAL_FAILURE

jmp Done

StoreIt:

mov ecx, [ebp + 10h]

mov [ecx], edx

xor eax, eax ; return success (VINF_SUCCESS == 0)

Done:

pop es

pop ebx

leave

; switch stack back and return.

push eax

call KernThunkStackTo32

pop eax

ret

ENDPROC RTR0Os2DHQueryDOSVar