'===========================================================================
' Subject: SMOOTH TEXT VERTICAL SCROLL        Date: 07-01-95 (00:00)       
'  Author: The ABC Programmer                 Code: ASM, QB, PDS           
'  Origin: Used within The ABC Reader       Packet: ASMCODE.ABC
'===========================================================================
; Smooth Vertical Scroll by William Yu
; Purpose:  Scroll Up/Down certain portions of a Text Screen
; Used within The ABC Reader
; If you are unfimiliar with the registers, refer to the DOS Reference Guide

 .MODEL MEDIUM, BASIC
 .CODE

        PUBLIC Scroll
Scroll PROC FAR USES DI SI DS ES, TopRow:WORD, TopCol:WORD, BotRow:WORD, BotCol:WORD, BLines:WORD, Attr:WORD, WhichWay:WORD

        MOV BX, WhichWay  ;Scroll Up/Down  6/7
        MOV AH, [BX]      ;Or you can have two seperate procedures ScrollUp/ScrollDown
        MOV BX, TopRow    ;Top Row
        MOV CH, [BX]
        MOV BX, TopCol    ;Top Column
        MOV CL, [BX]
        MOV BX, BotRow    ;Bottom Row
        MOV DH, [BX]
        MOV BX, BotCol    ;Botton Column
        MOV DL, [BX]
        MOV BX, BLines    ;# Lines Blanked
        MOV AL, [BX]
        MOV BX, Attr      ;Attribute to Use
        MOV BH, [BX]
        INT 10H

        RET 
Scroll ENDP
        END