Category : Dbase (Clipper, FoxBase, etc) Languages Source Code
Archive   : ASMFILE.ZIP
Filename : ROLLSCRN.ASM

; Title: ROLLSCRN.ASM
; Author: F. Ho
; Date: sometime 1985
; Syntax: DO ROLLUP WITH 1,2,3,4
; DO ROLLDN WITH 1,2,3,4
; Note: - rollup = rolls UP that part of the screen specified by
; the coordinates
; - rolldn = rolls DOWN that part of the screen specified
; by the coordinates
;
public ROLLUP ; declare as public
public ROLLDN ;
;
extrn _PARNI:far ; declare as external of type far
extrn _RET:far ;
;
;
datasg segment para 'DATA' ; start of data segment
;
TOP db 0h ; top -
LEFT db 0h ; left corner
BOTTOM db 0h ; bottom -
RIGHT db 0h ; right corner
;
datasg ends ; end of data segment
;
;
_prog segment byte ; start of code segment
assume cs:_prog,ds:datasg,es:_prog
;
ROLLUP proc far ; start of ROLLUP process
push bp ; preserve return address
mov bp,sp

push ds ; save registers
push es ;

mov ax,1 ; take 1st para
push ax
call _PARNI
add sp,2 ; restore stack
mov TOP,al ; assign 1st para to TOP

mov ax,2 ; take 2nd para
push ax
call _PARNI
add sp,2
mov LEFT,al ; assign to LEFT

mov ax,3 ; take 3rd para
push ax
call _PARNI
add sp,2
mov BOTTOM,al ; assign to BOTTOM

mov ax,4 ; take 4th para
push ax
call _PARNI
add sp,2
mov RIGHT,al ; assign to right

push cx ; preserve coordinate
push dx ; registers

mov ch,TOP ; assign TOP to high CX
mov cl,LEFT ; assign LEFT to low CX
mov dh,BOTTOM ; assign BOTTOM to high DX
mov dl,RIGHT ; assign RIGHT to low DX

xor ax,ax ; zero out AX
push ax
mov ax,0601h ; request roll up service
mov bh,07 ; normal attribute
int 10h ; issue video int

pop ax ; restore registers
pop dx ; before calling RETs
pop cx ; |

pop es ; |
pop ds ; |
pop bp ; |

call _RET ; Clipper return (actual cleaning)

ret ; actual physical return
ROLLUP endp ; end of process
;
;
ROLLDN proc far
push bp
mov bp,sp

push ds
push es

mov ax,1
push ax
call _PARNI
add sp,2
mov TOP,al

mov ax,2
push ax
call _PARNI
add sp,2
mov LEFT,al

mov ax,3
push ax
call _PARNI
add sp,2
mov BOTTOM,al
mov ax,4
push ax
call _PARNI
add sp,2
mov RIGHT,al

push cx
push dx

mov ch,TOP
mov cl,LEFT
mov dh,BOTTOM
mov dl,RIGHT

xor ax,ax
push ax
mov ax,0701h ; request roll down service
mov bh,07
int 10h

pop ax
pop dx
pop cx

pop es
pop ds
pop bp

call _RET

ret
ROLLDN endp
;
_prog ends
end