13e1
TITLE  MCGADump.ASM
;====
;====  Dumps MCGA screens (640x480x256) to disk
;====
;--------------------------------------------------------------------

CSEG    SEGMENT
        ASSUME CS:CSEG,DS:CSEG
        ORG 100H

Start:  jmp install_TSR

;================================
Org_Rutin DD ?
;================================

vidseg dw 0A000h

;-------------------------------------------------------------------

Start_TSR:                              ;H„r startar den programkod som
                                        ;kommer att bli minnesresident
Our_Layer PROC FAR
          ASSUME CS:CSEG,DS:CSEG        ;M†ste deklareras i denna del som
                                        ;f”rblir i minnet
        push ds                         ;DS-registrets v„rde sparas f”r
                                        ;att †terh„mtas vid †terhoppet
        push cs                         ;Under arbetet i 'Our_Layer' m†ste
        pop ds                          ;DS ha samma v„rde som CS annars
                                        ;kommer l„sning/skrivning fr†n/till
                                        ;minne att g† till fel datasegment

        sti                             ;F”r ordningens skull f”r att
                                        ;m”jligg”ra nytt interrupt

        pushf                           ;ett INT simuleras
        call Org_Rutin                  ;Originalrutinen anropas

;---------------------------------------------------------------------
;   Till denna punkt †terkommer vi sedan originalrutinen exekverats
;---------------------------------------------------------------------

        call ScrDump

        pop ds                          ;Det v„rde DS hade vid inhopp
                                        ;†terh„mtas
        iret                            ;Kontrollen tillbaka till
                                        ;anropande program (DOS)

Our_Layer ENDP


ScrDump  PROC NEAR
         ASSUME CS:CSEG,DS:CSEG

         push ax
         push bx
         push cx
         push dx

         mov ah,3ch                      ; create dump file
         mov cx,00h
         mov dx,offset fname
         int 21h

         mov ah,03dh                     ;Open for writing
         mov al,01h
         int 21h

         mov handle,ax

         mov cx,256
         mov DACreg,0

savepal:
         push cx

         mov ah,10h                       ;Save DAC palette
         mov al,15h                       
         mov bh,00
         mov bl,DACreg
         int 10h         
         inc DACreg

         mov red,dh
         mov green,ch
         mov blue,cl

         mov ah,40h
         mov bx,handle
         mov cx,1
         mov dx,offset red
         int 21h

         mov ah,40h
         mov cx,1
         mov dx,offset green
         int 21h

         mov ah,40h
         mov cx,1
         mov dx,offset blue
         int 21h

         pop cx
         loop savepal

;	mov ch,green            ;ch=green value
;	mov cl,blue             ;cl=blue value
;	mov dh,red              ;dh=red value


         mov ah,40h                       ;Write screen to dump file
         mov cx,64000                     ;64000 bytes
         mov ds,vidseg                    ;MCGA video adress
         mov dx,0                         ;Start of segment
         int 21h

         mov ah,3eh                       ;Close the dump file
         int 21h 

         pop dx
         pop cx
         pop bx
         pop ax

         ret

ScrDump  ENDP

handle dw 0

red db 0
green db 0
blue db 0

DACreg db 0
fname db 'MCGA.DMP',0

;----------------------------------------------------------------------
End_TSR:                                ;Minnesresident del slut
;=======================================================================


msgstr db 'MCGADump Installed. Press Alt-PrtScr to grab screen',13,10,'$'

Install_TSR:
        ASSUME CS:CSEG,DS:CSEG

        mov ah,09h
        mov dx,offset msgstr
        int 21h

        push cs                         ;DS m†ste peka p† r„tt segment
        pop ds                          ;d† vi skall ladda om vektorn

        mov al,05h                      ;H„mta vektorn till INT 05 (PrintScr)
        mov ah,35h
        int 21h

        mov word ptr Org_Rutin,BX       ;Org_Rutinens OFFSET h„mtas
        mov word ptr Org_Rutin+2,es     ;Segment sparas

        mov dx,OFFSET Start_TSR         ;Peka p† v†rt skikt
        mov al,05h                      ;Int 05h
        mov ah,25h                      ;Ladda om vektor
        int 21h

        mov dx,OFFSET End_TSR           ;Peka p† slutet p† den del som
                                        ;skall bli minnesresident
        int 27h                         ;G”r minnesresident

;-------------------------------------------------------------------------
CSEG    ENDS
        END Start
;--------------------------------------------------------------------------
.

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