cc65/libsrc/atari/cgetc.s

;
; Christian Groessler, November-2002
;
; get a char from the keyboard
; char cgetc(void)
;

        .include "atari.inc"
        .export _cgetc,setcursor
        .import KEYBDV_handler
        .import cursor,mul40

_cgetc:
        jsr     setcursor
        lda     #12
        sta     ICAX1Z          ; fix problems with direct call to KEYBDV
.ifndef __ATARIXL__
        jsr     @1
.else
        jsr     KEYBDV_handler
.endif
        ldx     #0
        rts

.ifndef __ATARIXL__
@1:     lda     KEYBDV+5
        pha
        lda     KEYBDV+4
        pha
        rts
.endif

.proc   setcursor

        ldy     #0
        lda     OLDCHR
        sta     (OLDADR),y

        lda     ROWCRS
        jsr     mul40
        clc
        adc     SAVMSC          ; add start of screen memory
        sta     OLDADR
        txa
        adc     SAVMSC+1
        sta     OLDADR+1
        lda     COLCRS
        adc     OLDADR
        sta     OLDADR
        bcc     nc
        inc     OLDADR+1
nc:     lda     (OLDADR),y
        sta     OLDCHR

        ldx     cursor          ; current cursor setting as requested by the user
        beq     off
        ldx     #0
        beq     cont

off:    inx
cont:   stx     CRSINH          ; update system variable

        beq     turnon
        and     #$7f            ; clear high bit / inverse flag
finish: sta     (OLDADR),y      ; update on-screen display
        rts

turnon: ora     #$80            ; set high bit / inverse flag
        bne     finish

.endproc