GT-6144 Subroutine

SUBROUTINE TO SET UP GRAPHICS PIA AND CLEAR SCREEN

<br />
TO ENTER:<br />
   IN MACHINE LANGUAGE- JSR $0300<br />
                        (20 00 03)</p>
<p>   IN BASIC -           CALL 768</p>
<p>0300-     48          PHA<br />
0301-     8A          TXA<br />
0302-     48          PHA<br />
0303-     98          TYA<br />
0304-     48          PHA<br />
0305-     A9 00       LDA   #$00<br />
0307-     8D 0B D0    STA   $D00B<br />
030A-     A9 FF       LDA   #$FF<br />
030C-     8D 0A D0    STA   $D00A<br />
030F-     A0 2C       LDA   #$2C<br />
0311-     8D 0B D0    STA   $D00B<br />
0314-     A2 00       LDX   #$00<br />
0316-     A0 00       LDY   #$00<br />
0318-     8A          TXA<br />
0319-     8D 0A D0    STA   $D00A<br />
031C-     98          TYA<br />
031D-     09 80       ORA   #$80<br />
031F-     8D 0A D0    STA   $D00A<br />
0322-     C9 FF       CMP   #$FF<br />
0324-     10 04       BPL   $032A<br />
0326-     C8          INY<br />
0327-     4C 1C 03    JMP   $031C<br />
032A-     8A          TXA<br />
032B-     C9 3F       CMP   #$3F<br />
032D-     10 04       BPL   $0333<br />
032F-     E8          INX<br />
0330-     4C 16 03    JMP   $0316<br />
0333-     68          PLA<br />
0334-     A8          TAY<br />
0335-     68          PLA<br />
0336-     AA          TAX<br />
0337-     68          PLA<br />
0338-     60          RTS<br />
0339-     FF          ???<br />
033A-     FF          ???<br />
033B-     FF          ???<br />
033C-     FF          ???<br />
033D-     FF          ???<br />
033E-     FF          ???<br />