mirror of
https://github.com/cc65/cc65.git
synced 2024-11-14 05:05:45 +00:00
36 lines
466 B
ArmAsm
36 lines
466 B
ArmAsm
;
|
|
; Christian Groessler, Apr-2000
|
|
;
|
|
; void clrscr (void);
|
|
;
|
|
|
|
.export _clrscr
|
|
.include "atari.inc"
|
|
.importzp ptr1
|
|
|
|
_clrscr:lda SAVMSC ; screen memory
|
|
sta ptr1
|
|
lda SAVMSC+1
|
|
clc
|
|
adc #>(40*24)
|
|
sta ptr1+1
|
|
lda #0 ; screen code of space char
|
|
ldy #<(40*24) ; 40x24: size of default atari screen
|
|
ldx #>(40*24)
|
|
_clr1: sta (ptr1),y
|
|
dey
|
|
bne _clr1
|
|
sta (ptr1),y
|
|
dex
|
|
bmi done
|
|
ldy ptr1+1
|
|
dey
|
|
sty ptr1+1
|
|
ldy #255
|
|
jmp _clr1
|
|
|
|
done: sta COLCRS
|
|
sta ROWCRS
|
|
rts
|
|
|