mirror of
https://github.com/cc65/cc65.git
synced 2024-07-16 02:28:57 +00:00
26 lines
502 B
ArmAsm
26 lines
502 B
ArmAsm
;
|
|
; void clrscr (void);
|
|
;
|
|
.export _clrscr
|
|
.include "c1p.inc"
|
|
|
|
; Adapted from the Challenger Character Graphics
|
|
; Reference Manual, "2.3.3 MACHINE LANGUAGE SCREEN CLEAR"
|
|
; This is self-modifying code!
|
|
BANKS = VIDEORAMSIZE / $100
|
|
|
|
_clrscr:
|
|
lda #$20 ;' '
|
|
ldy #BANKS
|
|
ldx #$00
|
|
staloc:
|
|
sta SCRNBASE,X
|
|
inx
|
|
bne staloc
|
|
inc staloc+2
|
|
dey
|
|
bne staloc
|
|
lda #>(SCRNBASE) ; load high byte
|
|
sta staloc+2 ; restore base address
|
|
rts
|