00001 *************************
00002 *
00003 * SCROLL.ASM
00004 * MDJ 09-25-90
00005 *
00006 * SCROLLS THE SCREEN UP
00007 * ONE TEXT LINE & LEAVES
00008 * THE CURSOR AT THE LEFT
00009 * END (START) OF THE 
00010 * BOTTOM LINE - RESETS
00011 * THE ADVANCE CODE
00012 *
00013 *************************
00014 *
00015 * U AND S STACKS MUST
00016 * ALREADY BE INITIALIZED
00017 *
00018 * NO ENTRY CONDITIONS
00019 *
00020 * ON RETURN, ADVANCE CODE
00021 * IS RESET TO ZERO
00022 *
00023 *************************
00024 *
00025 BEGGRP  EQU     $BA     START OF CURRENT GRAPHICS PAGE
00026 XCURS   EQU     $F3     CURSOR X LOCATION
00027 YCURS   EQU     $F5     CURSOR Y LOCATION
00028 ADVCOD  EQU     $F7     ADVANCE CODE
00029         ORG     $3F33
00030 SCROLL  PSHS    A,B,X,Y,U
00031         LDD     BEGGRP  GET START OF PAGE
00032         TFR     D,X
00033         ADDD    #256
00034         TFR     D,Y
00035         LDU     #5888
00036 SCROL1  LDA     ,Y+
00037         STA     ,X+
00038         LEAU    -1,U
00039         CMPU    #0
00040         BNE     SCROL1
00041         LDU     #256
00042         LDA     #$FF
00043 SCROL2  STA     ,X+
00044         LEAU    -1,U
00045         CMPU    #0
00046         BNE     SCROL2
00047         LDX     #0
00048         STX     XCURS   NEW CURSOR X LOCATION
00049         LDX     #184
00050         STX     YCURS   NEW CURSOR Y LOCATION
00051         CLR     ADVCOD  RESET ADVANCE CODE
00052         PULS    A,B,X,Y,U
00053 ZEND    RTS
00054         END
 
 
 
 
 
 
 
 
 
 
 
 
