846 lines
27 KiB
NASM
846 lines
27 KiB
NASM
;
|
||
; Command & Conquer Red Alert(tm)
|
||
; Copyright 2025 Electronic Arts Inc.
|
||
;
|
||
; This program is free software: you can redistribute it and/or modify
|
||
; it under the terms of the GNU General Public License as published by
|
||
; the Free Software Foundation, either version 3 of the License, or
|
||
; (at your option) any later version.
|
||
;
|
||
; This program is distributed in the hope that it will be useful,
|
||
; but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
; GNU General Public License for more details.
|
||
;
|
||
; You should have received a copy of the GNU General Public License
|
||
; along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||
;
|
||
|
||
;***************************************************************************
|
||
;** C O N F I D E N T I A L --- W E S T W O O D S T U D I O S **
|
||
;***************************************************************************
|
||
;* *
|
||
;* Project Name : Mono Screen system *
|
||
;* *
|
||
;* File Name : MONO.ASM *
|
||
;* *
|
||
;* Programmer : Jeff Wilson *
|
||
;* *
|
||
;* Start Date : March 28, 1994 *
|
||
;* *
|
||
;* Last Update : September 8, 1994 [IML] *
|
||
;* *
|
||
;*-------------------------------------------------------------------------*
|
||
;* Functions: *
|
||
;GLOBAL MonoScreen :DWORD
|
||
;GLOBAL MonoEnabled :DWORD
|
||
;
|
||
;GLOBAL C Mono_Set_Cursor :NEAR
|
||
;GLOBAL C Mono_Clear_Screen :NEAR
|
||
;GLOBAL C Mono_Scroll :NEAR
|
||
;GLOBAL C Mono_Put_Char :NEAR
|
||
;GLOBAL C Mono_Draw_Rect :NEAR
|
||
;
|
||
;GLOBAL C _Mono_Text_Print :NEAR
|
||
;GLOBAL C Mono_Text_Print :NEAR
|
||
;
|
||
;GLOBAL C Mono_Print :NEAR
|
||
;
|
||
;GLOBAL C Mono_View_Page :NEAR
|
||
;* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - *
|
||
|
||
|
||
IDEAL
|
||
P386
|
||
MODEL USE32 FLAT
|
||
|
||
LOCALS ??
|
||
|
||
|
||
;
|
||
; External declares so these functions can be called
|
||
;
|
||
GLOBAL MonoScreen :DWORD
|
||
GLOBAL MonoEnabled :DWORD
|
||
|
||
GLOBAL Mono_Set_Cursor :NEAR ; done
|
||
GLOBAL Mono_Clear_Screen :NEAR ; done
|
||
GLOBAL Mono_Scroll :NEAR ; done
|
||
GLOBAL Mono_Put_Char :NEAR ; done
|
||
GLOBAL Mono_Draw_Rect :NEAR ; done
|
||
GLOBAL _Mono_Text_Print :NEAR ; done
|
||
GLOBAL Mono_Text_Print :NEAR ; done
|
||
GLOBAL Mono_Print :NEAR ; done
|
||
GLOBAL Mono_View_Page :NEAR ; done
|
||
|
||
;
|
||
; Equates used in this file
|
||
;
|
||
NULL = 0 ; null code
|
||
CR = 13 ; carriage return code
|
||
CPL = 80 ; characters per line
|
||
LPS = 25 ; lines per screen
|
||
|
||
|
||
DATASEG
|
||
|
||
MonoX DD 0
|
||
MonoY DD 0
|
||
MonoOff DD 0
|
||
MonoScreen DD 0b0000h ;Deffault to Real mode!
|
||
MonoEnabled DD 0 ; Is mono printing enabled?
|
||
|
||
;====================================================================
|
||
|
||
CharData DB 0DAh,0C4h,0BFh,0B3h,0D9h,0C4h,0C0h,0B3h ; Single line
|
||
DB 0D5h,0CDh,0B8h,0B3h,0BEh,0CDh,0D4h,0B3h ; Double horz.
|
||
DB 0D6h,0C4h,0B7h,0BAh,0BDh,0C4h,0D3h,0BAh ; Double vert.
|
||
DB 0C9h,0CDh,0BBh,0BAh,0BCh,0CDh,0C8h,0BAh ; Double line.
|
||
|
||
|
||
; x,y,dist
|
||
BoxData DB 1,0,0 ; Upper left corner.
|
||
DB 1,0,1 ; Top edge.
|
||
DB 0,1,0 ; Upper right corner.
|
||
DB 0,1,2 ; Right edge.
|
||
DB -1,0,0 ; Bottom right corner.
|
||
DB -1,0,1 ; Bottom edge.
|
||
DB 0,-1,0 ; Bottom left corner.
|
||
DB 0,-1,2 ; Left edge.
|
||
DB 0,0,-1 ; End of list.
|
||
|
||
; Mono page segment layout array.
|
||
PageMap DD 0,1,2,3,4,5,6,7
|
||
|
||
;===================================================================
|
||
|
||
CODESEG
|
||
|
||
|
||
;***************************************************************************
|
||
;* Map_Segment_To_Address_ -- Translate a 16bit Seg:Offset address to a *
|
||
;* Linear address. *
|
||
;* *
|
||
;* *
|
||
;* *
|
||
;* INPUT: *
|
||
;* *
|
||
;* OUTPUT: *
|
||
;* *
|
||
;* WARNINGS: *
|
||
;* *
|
||
;* HISTORY: *
|
||
;*=========================================================================*
|
||
; int Map_Segment_To_Address ( unsigned seg , unsigned offset );
|
||
|
||
|
||
|
||
;***************************************************************************
|
||
;* MONO_SET_CURSOR -- Sets the mono cursor to specified coordinates. *
|
||
;* *
|
||
;* *
|
||
;* *
|
||
;* INPUT: *
|
||
;* *
|
||
;* OUTPUT: *
|
||
;* *
|
||
;* WARNINGS: *
|
||
;* *
|
||
;* HISTORY: *
|
||
;*=========================================================================*
|
||
; void Mono_Set_Cursor(int x, int y);
|
||
|
||
|
||
PROC Mono_Set_Cursor C near
|
||
|
||
USES eax , ebx , edx
|
||
|
||
ARG xpos : DWORD
|
||
ARG ypos : DWORD
|
||
|
||
cmp [MonoEnabled],0
|
||
je ??exit
|
||
|
||
; mov ax,cs
|
||
; and ax,7
|
||
; or ax,SS_DATA
|
||
|
||
; mov ds,ax
|
||
; mov es,ax
|
||
|
||
; sub eax,eax
|
||
|
||
mov eax,[ypos]
|
||
; mov ah,CPL
|
||
; imul ah
|
||
lea eax , [ eax + 4 * eax ] ; multiply by CPL
|
||
shl eax , 4
|
||
|
||
; sub ebx,ebx
|
||
mov ebx,[xpos]
|
||
add ebx,eax
|
||
|
||
; Update cursor position.
|
||
mov edx,03B4h
|
||
|
||
mov al,0Eh ; High byte register set.
|
||
out dx,al
|
||
inc edx
|
||
mov al,bh
|
||
out dx,al ; Set high byte.
|
||
|
||
dec edx
|
||
mov al,0Fh ; Low byte register set.
|
||
out dx,al
|
||
inc edx
|
||
mov al,bl
|
||
out dx,al ; Set low byte.
|
||
|
||
; Update the globals.
|
||
add ebx,ebx
|
||
mov [MonoOff],ebx
|
||
mov eax,[xpos]
|
||
mov [MonoX],eax
|
||
mov eax,[ypos]
|
||
mov [MonoY],eax
|
||
|
||
??exit:
|
||
ret
|
||
|
||
ENDP Mono_Set_Cursor
|
||
|
||
|
||
;***************************************************************************
|
||
;* MONO_CLEAR_SCREEN -- Clears the mono screen and homes cursor. *
|
||
;* *
|
||
;* *
|
||
;* *
|
||
;* INPUT: *
|
||
;* *
|
||
;* OUTPUT: *
|
||
;* *
|
||
;* WARNINGS: *
|
||
;* *
|
||
;* HISTORY: *
|
||
;*=========================================================================*
|
||
; void Mono_Clear_Screen(void);
|
||
|
||
PROC Mono_Clear_Screen C near
|
||
|
||
USES eax , ecx , edi
|
||
|
||
cmp [MonoEnabled],0
|
||
je ??exit
|
||
|
||
; mov ax,cs
|
||
; and ax,7
|
||
; or ax,SS_DATA
|
||
|
||
; mov ds,ax
|
||
; mov es,ax
|
||
|
||
; mov eax,[MonoScreen] ; ES:DI = Mono RAM address.
|
||
; mov es,ax
|
||
; sub edi,edi
|
||
mov edi , [ MonoScreen ]
|
||
mov eax,02000200h ; Clear leave attrib bit normal.
|
||
mov ecx,8000h/4 ; Number of longs to clear.
|
||
rep stosd ; Clear the mono screen.
|
||
|
||
push 0
|
||
push 0
|
||
|
||
call Mono_Set_Cursor
|
||
add esp , 8
|
||
|
||
??exit:
|
||
ret
|
||
|
||
ENDP Mono_Clear_Screen
|
||
|
||
|
||
;***************************************************************************
|
||
;* MONO_SCROLL -- Scroll the mono screen up specified lines. *
|
||
;* *
|
||
;* *
|
||
;* *
|
||
;* INPUT: *
|
||
;* *
|
||
;* OUTPUT: *
|
||
;* *
|
||
;* WARNINGS: *
|
||
;* *
|
||
;* HISTORY: *
|
||
;*=========================================================================*
|
||
; void Mono_Scroll(DWORD lines);
|
||
PROC Mono_Scroll C near
|
||
|
||
USES eax , ebx , ecx , edx , edi , esi
|
||
ARG lines : DWORD
|
||
|
||
cmp [MonoEnabled],0
|
||
je ??exit
|
||
|
||
; mov ax,cs
|
||
; and ax,7
|
||
; or ax,SS_DATA
|
||
|
||
; mov ds,ax
|
||
; mov es,ax
|
||
|
||
; xor eax,eax ; clear eax so no need for sign extend
|
||
mov eax, [lines] ; get lines available
|
||
or eax,eax ; any lines to scroll?
|
||
je short ??fini ; =>NO
|
||
|
||
mov ebx,eax ; set line counter
|
||
|
||
mov edx,[MonoY] ; get row count
|
||
ror edx,16 ; store it in high half of register
|
||
mov dx,[WORD PTR MonoOff] ; get column offset
|
||
ror edx,16
|
||
|
||
; mov eax,[MonoScreen] ; get selector for mono screen
|
||
; push ds ; save off data seg for later
|
||
; mov ds,ax ; set data source register
|
||
; mov es,ax ; and extra source register
|
||
|
||
sub eax,eax ; set to clear clear line
|
||
|
||
??looper:
|
||
mov ecx,(80*24) ; Number of words to move.
|
||
|
||
; xor edi,edi ; dst start at top of screen area
|
||
; mov esi,80*2 ; src start at next line down
|
||
mov edi , [ MonoScreen ]
|
||
lea esi , [ 80 * 2 + edi ]
|
||
rep movsw ; Scroll the screen upward.
|
||
|
||
dec dx ; decrement Y counter
|
||
ror edx,16 ; switch to mono offset
|
||
sub dx,80*2 ; fix MonoOffset
|
||
ror edx,16 ; switch to y counter
|
||
|
||
mov ecx,40 ; Clear out the last line.
|
||
rep stosd ; by storing words across it
|
||
dec ebx ; last line?
|
||
|
||
jne ??looper ; =>NO
|
||
|
||
; reset data values
|
||
; pop ds ; restore the ds segment
|
||
mov [WORD PTR MonoY],dx ; store of the mono y position
|
||
ror edx,16 ; switch to screen offset
|
||
mov [WORD PTR MonoOff],dx ; store of the mono offset
|
||
|
||
??fini:
|
||
??exit:
|
||
ret
|
||
|
||
ENDP Mono_Scroll
|
||
|
||
|
||
;***************************************************************************
|
||
;* MONO_PUT_CHAR -- Output a character to the mono screen. *
|
||
;* *
|
||
;* *
|
||
;* *
|
||
;* INPUT: *
|
||
;* *
|
||
;* OUTPUT: *
|
||
;* *
|
||
;* WARNINGS: *
|
||
;* *
|
||
;* HISTORY: *
|
||
;*=========================================================================*
|
||
; void Mono_Put_Char(char character, int attrib=2);
|
||
|
||
PROC Mono_Put_Char C near
|
||
|
||
USES eax , edi
|
||
|
||
ARG character : BYTE
|
||
ARG attrib : DWORD
|
||
|
||
cmp [MonoEnabled],0
|
||
je ??exit
|
||
|
||
; mov ax,cs
|
||
; and ax,7
|
||
; or ax,SS_DATA
|
||
|
||
; mov ds,ax
|
||
|
||
mov edi,[MonoOff]
|
||
; mov eax,[MonoScreen]
|
||
; mov es,ax ; ES:DI = First character output pointer.
|
||
add edi , [ MonoScreen ]
|
||
|
||
; Output character to monochrome monitor.
|
||
mov al,[character]
|
||
mov ah,[BYTE PTR attrib]
|
||
; stosw
|
||
mov [ edi ] , ax
|
||
|
||
; Update cursor position.
|
||
inc [MonoX] ; X position moves.
|
||
|
||
mov eax,[MonoY]
|
||
push eax
|
||
mov eax,[MonoX]
|
||
push eax
|
||
|
||
call Mono_Set_Cursor
|
||
add esp,8
|
||
|
||
??exit:
|
||
ret
|
||
|
||
ENDP Mono_Put_Char
|
||
|
||
|
||
;***************************************************************************
|
||
;* MONO_DRAW_RECT -- Draw a rectangle using mono characters. *
|
||
;* *
|
||
;* *
|
||
;* *
|
||
;* INPUT: *
|
||
;* *
|
||
;* OUTPUT: *
|
||
;* *
|
||
;* WARNINGS: *
|
||
;* *
|
||
;* HISTORY: *
|
||
;*=========================================================================*
|
||
; void Mono_Draw_Rect(int x, int y, int w, int h, int attrib=2, int thick=0);
|
||
|
||
PROC Mono_Draw_Rect C near
|
||
|
||
USES eax , ebx , ecx , esi , edi
|
||
|
||
ARG xpos:DWORD
|
||
ARG ypos:DWORD
|
||
ARG width:DWORD
|
||
ARG height:DWORD
|
||
ARG attrib:DWORD
|
||
ARG thick:DWORD
|
||
|
||
cmp [MonoEnabled],0
|
||
je ??exit
|
||
|
||
; mov ax,cs
|
||
; and ax,7
|
||
; or ax,SS_DATA
|
||
|
||
; mov ds,ax
|
||
; mov es,ax
|
||
|
||
mov esi,OFFSET BoxData
|
||
mov edi,OFFSET CharData
|
||
|
||
; mov cl,3
|
||
; sub eax,eax
|
||
mov eax,[thick]
|
||
and eax,011b
|
||
shl eax,3
|
||
add edi,eax
|
||
|
||
; Prep width and height.
|
||
cmp [width],2
|
||
jb ??fini
|
||
|
||
cmp [height],2
|
||
jb ??fini
|
||
|
||
sub [width],2
|
||
sub [height],2
|
||
|
||
; Preserve cursor position for later restore.
|
||
mov ecx,[MonoX]
|
||
push ecx
|
||
mov ecx,[MonoY]
|
||
push ecx
|
||
|
||
; Cursor starts at upper left corner.
|
||
mov ecx,[ypos]
|
||
push ecx
|
||
mov ecx,[xpos]
|
||
push ecx
|
||
call Mono_Set_Cursor
|
||
add esp,8
|
||
|
||
??drawloop:
|
||
; Determine the number of characters to output.
|
||
mov ecx,[width]
|
||
cmp [BYTE PTR esi+2],1
|
||
je short ??gotlen
|
||
|
||
mov ecx,[height]
|
||
cmp [BYTE PTR esi+2],2
|
||
je short ??gotlen
|
||
|
||
mov ecx,1
|
||
??gotlen:
|
||
|
||
jecxz ??donerun
|
||
|
||
??runloop:
|
||
sub ebx,ebx
|
||
mov bl,[BYTE PTR edi]
|
||
|
||
; mov ebx,eax
|
||
sub eax,eax
|
||
mov al,[BYTE PTR attrib]
|
||
push eax
|
||
push ebx
|
||
|
||
call Mono_Put_Char
|
||
add esp,8
|
||
|
||
movsx eax,[BYTE PTR esi+1]
|
||
; cbw
|
||
add eax,[MonoY]
|
||
push eax
|
||
movsx eax,[BYTE PTR esi]
|
||
; cbw
|
||
add eax,[MonoX]
|
||
dec eax ; Undo cursor advance.
|
||
push eax
|
||
|
||
call Mono_Set_Cursor ; Properly advance cursor.
|
||
add esp,8
|
||
|
||
loop ??runloop
|
||
|
||
??donerun:
|
||
|
||
; Advance to next control entry.
|
||
add esi,3
|
||
inc edi
|
||
cmp [BYTE PTR esi+2],-1
|
||
jne ??drawloop
|
||
|
||
; Restore cursor to original position.
|
||
call Mono_Set_Cursor
|
||
add esp,8
|
||
|
||
??fini:
|
||
??exit:
|
||
ret
|
||
|
||
ENDP Mono_Draw_Rect
|
||
|
||
|
||
;***************************************************************************
|
||
;* MONO_TEXT_PRINT -- Prints text to the mono screen at coordinates. *
|
||
;* *
|
||
;* *
|
||
;* *
|
||
;* INPUT: *
|
||
;* *
|
||
;* OUTPUT: *
|
||
;* *
|
||
;* WARNINGS: *
|
||
;* *
|
||
;* HISTORY: *
|
||
;*=========================================================================*
|
||
; void Mono_Text_Print(void *text, int x, int y, int attrib, int update);
|
||
|
||
PROC _Mono_Text_Print C near
|
||
|
||
USES eax,ebx,ecx,edx,edi,esi
|
||
|
||
ARG text:DWORD
|
||
ARG xpos:DWORD
|
||
ARG ypos:DWORD
|
||
ARG attrib:DWORD
|
||
ARG update:DWORD
|
||
|
||
cmp [MonoEnabled],0
|
||
je ??exit
|
||
|
||
; mov ax,cs
|
||
; and ax,7
|
||
; or ax,SS_DATA
|
||
|
||
; mov ds,ax
|
||
; mov es,ax
|
||
|
||
; Preserve cursor coordinates for later restoration.
|
||
mov eax,[MonoY]
|
||
push eax
|
||
mov eax,[MonoX]
|
||
push eax
|
||
|
||
cmp [text],NULL
|
||
je ??fini
|
||
|
||
mov eax,[ypos]
|
||
push eax
|
||
mov eax,[xpos]
|
||
push eax
|
||
call Mono_Set_Cursor
|
||
add esp,8
|
||
|
||
mov esi,[text]
|
||
|
||
??charloop:
|
||
xor eax,eax
|
||
mov al,[BYTE PTR esi] ; Fetch character to output.
|
||
inc esi
|
||
|
||
; Stop processing on a NULL character.
|
||
or eax,eax
|
||
je short ??fini
|
||
|
||
; Special processing for a '\r' characters.
|
||
cmp eax,CR
|
||
je short ??cr
|
||
|
||
; Output character to monochrome monitor.
|
||
??normal:
|
||
; xor ah,ah
|
||
|
||
mov ebx,eax
|
||
mov eax,[attrib]
|
||
push eax
|
||
push ebx
|
||
call Mono_Put_Char
|
||
add esp,8
|
||
|
||
; Perform adjustments if wrapping past right margin.
|
||
cmp [WORD PTR MonoX],CPL
|
||
jb short ??nowrap
|
||
|
||
inc [ypos]
|
||
|
||
mov eax,[ypos]
|
||
push eax
|
||
; sub eax,eax
|
||
push 0
|
||
call Mono_Set_Cursor
|
||
add esp,8
|
||
|
||
jmp short ??nowrap
|
||
|
||
; Move to start of next line.
|
||
??cr:
|
||
inc [ypos]
|
||
|
||
mov eax,[ypos]
|
||
push eax
|
||
mov eax,[xpos]
|
||
push eax
|
||
call Mono_Set_Cursor
|
||
add esp,8
|
||
|
||
; Scroll the monochrome screen if necessary.
|
||
??nowrap:
|
||
cmp [MonoY],LPS
|
||
jb short ??noscroll
|
||
|
||
push 1
|
||
call Mono_Scroll
|
||
add esp,4
|
||
|
||
dec [ypos]
|
||
|
||
??noscroll:
|
||
jmp short ??charloop
|
||
|
||
??fini:
|
||
cmp [update],0
|
||
jne short ??noupdate
|
||
|
||
call Mono_Set_Cursor
|
||
??noupdate:
|
||
add esp,8
|
||
|
||
??exit:
|
||
ret
|
||
|
||
ENDP _Mono_Text_Print
|
||
|
||
;=====================================================================
|
||
|
||
PROC Mono_Text_Print C near
|
||
USES eax
|
||
ARG text:DWORD
|
||
ARG xpos:DWORD
|
||
ARG ypos:DWORD
|
||
ARG attrib:DWORD
|
||
|
||
|
||
cmp [MonoEnabled],0
|
||
je ??exit
|
||
|
||
; sub eax,eax
|
||
push 0
|
||
mov eax,[attrib]
|
||
push eax
|
||
mov eax,[ypos]
|
||
push eax
|
||
mov eax,[xpos]
|
||
push eax
|
||
mov eax,[text]
|
||
push eax
|
||
|
||
call _Mono_Text_Print
|
||
add esp,20
|
||
|
||
??exit:
|
||
ret
|
||
|
||
ENDP Mono_Text_Print
|
||
|
||
|
||
|
||
;***************************************************************************
|
||
;* MONO_PRINT -- Prints text to the mono screen at current pos. *
|
||
;* *
|
||
;* *
|
||
;* *
|
||
;* INPUT: *
|
||
;* *
|
||
;* OUTPUT: *
|
||
;* *
|
||
;* WARNINGS: *
|
||
;* *
|
||
;* HISTORY: *
|
||
;*=========================================================================*
|
||
; void Mono_Print(void *text);
|
||
|
||
PROC Mono_Print C near
|
||
|
||
USES eax
|
||
|
||
ARG text:DWORD
|
||
|
||
cmp [MonoEnabled],0
|
||
je ??exit
|
||
|
||
; mov ax,cs
|
||
; and ax,7
|
||
; or ax,SS_DATA
|
||
|
||
; mov ds,ax
|
||
; mov es,ax
|
||
|
||
; mov eax,1
|
||
push 1
|
||
; mov eax,2
|
||
push 2
|
||
mov eax,[MonoY]
|
||
push eax
|
||
mov eax,[MonoX]
|
||
push eax
|
||
mov eax,[text]
|
||
push eax
|
||
|
||
call _Mono_Text_Print
|
||
add esp,20
|
||
|
||
??exit:
|
||
ret
|
||
|
||
ENDP Mono_Print
|
||
|
||
;***************************************************************************
|
||
;* Mono_View_Page -- page in a mono screen *
|
||
;* *
|
||
;* Displays the specified page in displayable mono memory area. *
|
||
;* *
|
||
;* INPUT: WORD page = which page of memory we will use for storage *
|
||
;* *
|
||
;* OUTPUT: old_page *
|
||
;* *
|
||
;* WARNINGS: none. *
|
||
;* *
|
||
;* HISTORY: *
|
||
;*=========================================================================*
|
||
; int cdecl Mono_View_Page(int page);
|
||
|
||
|
||
PROC Mono_View_Page C near
|
||
|
||
USES eax,ebx,ecx,edx,edi,esi
|
||
|
||
ARG page:DWORD
|
||
|
||
LOCAL oldpage:DWORD
|
||
|
||
cmp [MonoEnabled],0
|
||
je ??exit
|
||
|
||
cld
|
||
|
||
; mov ax,cs
|
||
; and ax,7
|
||
; or ax,SS_DATA
|
||
|
||
; mov ds,ax
|
||
; mov es,ax
|
||
|
||
; Prepare the original page number for return to caller.
|
||
mov ebx,[PageMap]
|
||
mov [oldpage],ebx
|
||
|
||
; If the desired page is already displayed, then don't do anything.
|
||
mov eax,[page]
|
||
cmp eax,ebx
|
||
je short ??fini
|
||
|
||
; Verify that page specified is legal.
|
||
cmp eax,7
|
||
ja short ??fini
|
||
|
||
; Find where the logical page to display is actually located.
|
||
mov ecx,8
|
||
|
||
mov edi,OFFSET PageMap
|
||
repne scasd
|
||
neg ecx
|
||
add ecx,7 ; ECX = where desired page is located.
|
||
|
||
; Swap the page ID bytes in the PageMap array.
|
||
sub edi,4
|
||
mov ebx,[PageMap]
|
||
mov eax,[edi]
|
||
mov [edi],ebx
|
||
mov [PageMap],eax
|
||
|
||
; Set DS and ES to point to each page.
|
||
; mov eax,[MonoScreen]
|
||
; mov ds,ax
|
||
mov esi , [ MonoScreen ]
|
||
; shl ecx,8
|
||
shl ecx , 12
|
||
; add ecx,edi ; NO Addition to selectors!
|
||
lea edi , [ esi + ecx ]
|
||
|
||
; mov edi,ecx
|
||
; xor esi,esi
|
||
|
||
; Exchange the two pages.
|
||
mov ecx,1000H/4
|
||
|
||
??looper:
|
||
mov edx,[edi]
|
||
mov ebx,[esi]
|
||
mov [edi],ebx
|
||
mov [esi],edx
|
||
add esi,4
|
||
add edi,4
|
||
loop ??looper
|
||
|
||
; Return with the original page number.
|
||
??fini:
|
||
??exit:
|
||
mov eax,[oldpage]
|
||
ret
|
||
|
||
ENDP Mono_View_Page
|
||
|
||
END
|
||
|