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;
; Mark Keates, Christian Groessler, Piotr Fusik
;
; void cputcxy (unsigned char x, unsigned char y, char c);
; void cputc (char c);
;
.export _cputcxy, _cputc
.export plot, cputdirect, putchar
.import gotoxy, _mul40
.importzp tmp4,ptr4
.import _revflag,setcursor
.include "atari.inc"
_cputcxy:
pha ; Save C
jsr gotoxy ; Set cursor, drop x and y
pla ; Restore C
_cputc:
cmp #$0D ; CR
bne L4
lda #0
sta COLCRS
beq plot ; return
L4: cmp #$0A ; LF
beq newline
cmp #ATEOL ; Atari-EOL?
beq newline
asl a ; shift out the inverse bit
adc #$c0 ; grab the inverse bit; convert ATASCII to screen code
bpl codeok ; screen code ok?
eor #$40 ; needs correction
codeok: lsr a ; undo the shift
bcc cputdirect
eor #$80 ; restore the inverse bit
cputdirect: ; accepts screen code
jsr putchar
; advance cursor
inc COLCRS
lda COLCRS
cmp #40
bcc plot
lda #0
sta COLCRS
.export newline
newline:
inc ROWCRS
lda ROWCRS
cmp #24
bne plot
lda #0
sta ROWCRS
plot: jsr setcursor
ldy COLCRS
ldx ROWCRS
rts
; turn off cursor, update screen, turn on cursor
putchar:
pha ; save char
ldy #0
lda OLDCHR
sta (OLDADR),y
lda ROWCRS
jsr _mul40 ; destroys tmp4, carry is cleared
adc SAVMSC ; add start of screen memory
sta ptr4
txa
adc SAVMSC+1
sta ptr4+1
pla ; get char again
ora _revflag
sta OLDCHR
ldy COLCRS
sta (ptr4),y
jmp setcursor
|
