cc65/libsrc/geos-common/conio/cputc.s

;
; Maciej 'YTM/Elysium' Witkowiak
;
; 27.10.2001
; 06.03.2002
; 25.07.2005

; void cputcxy (unsigned char x, unsigned char y, char c);
; void cputc (char c);

; TODO:
; TAB (should be implemented)
; other special characters directly from keyboard are unsafe, though some might be
; implemented:
; HOME, UPLINE, ULINEON, ULINEOFF, REV_ON, REV_OFF, BOLDON, ITALICON, OUTLINEON, PLAINTEXT
; and cursor movement, maybe stuff like INSERT too
;
; these must be ignored:
; ESC_GRAPHICS, ESC_RULER, GOTOX, GOTOY, GOTOXY, NEWCARDSET, all 1..8
;
; note that there are conflicts between control characters and keyboard:
; HOME = KEY_ENTER, KEY_HOME = REV_ON, 
; UPLINE = ?, KEY_UPARROW = GOTOY, ...

	    .export _cputcxy, _cputc
	    .import _gotoxy, fixcursor
	    .import popa
	    .import xsize,ysize
	    .importzp cursor_x, cursor_y, cursor_c, cursor_r

	    .include "const.inc"
	    .include "geossym.inc"
	    .include "jumptab.inc"

_cputcxy:
	pha    			; Save C
	jsr popa		; Get Y
	jsr _gotoxy		; Set cursor, drop x
	pla			; Restore C

; Plot a character - also used as internal function

_cputc:
	tax			; save character
; some characters 0-31 are not safe for PutChar
	cmp #$20
	bcs L1
	cmp #CR
	beq do_cr
	cmp #LF
	beq do_lf
	cmp #KEY_DELETE
	bne L0
	ldx #BACKSPACE
	sec
	bcs L2
L0:	rts

L1:	clc
L2:	php
	lda cursor_x
	sta r11L
	lda cursor_x+1
	sta r11H
	lda cursor_y
	clc
	adc #6			; 6 pixels down to the baseline
	sta r1H
	txa
	jsr PutChar
	plp
	bcs fix_cursor

	inc cursor_c
	lda cursor_c
	cmp xsize		; hit right margin?
	bne fix_cursor
	lda #0			; yes - do cr+lf
	sta cursor_c
do_lf:	inc cursor_r
	lda cursor_r
	cmp ysize		; hit bottom margin?
	bne fix_cursor
	dec cursor_r		; yes - stay in the last line

fix_cursor:
	jmp fixcursor

do_cr:	lda #0
	sta cursor_c
	beq fix_cursor