diff options
Diffstat (limited to 'conio/clrscr.s')
| -rw-r--r-- | conio/clrscr.s | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/conio/clrscr.s b/conio/clrscr.s new file mode 100644 index 0000000..5881aea --- /dev/null +++ b/conio/clrscr.s @@ -0,0 +1,35 @@ +; +; Christian Groessler, Apr-2000 +; +; void clrscr (void); +; + + .export _clrscr + .include "atari.inc" + .importzp ptr1 + +SCRSIZE = 960 ; 40x24: size of default atari screen + +_clrscr:lda SAVMSC ; screen memory + sta ptr1 + lda SAVMSC+1 + clc + adc #>(SCRSIZE-1) + sta ptr1+1 + lda #0 ; screen code of space char + sta OLDCHR + ldy #<(SCRSIZE-1) + ldx #>(SCRSIZE-1) +_clr1: sta (ptr1),y + dey + bne _clr1 + sta (ptr1),y + dex + bmi done + dec ptr1+1 + dey + jmp _clr1 + +done: sta COLCRS + sta ROWCRS + rts |