cc65/libsrc/c1p/clrscr.s

;
; 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
Implemented clrscr routine for C1P 2014-11-08 00:14:46 +00:00			`;`
			`; 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`

Adapt to assembler coding conventions. 2014-11-16 20:57:59 +00:00			`_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`