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cc65/libsrc/c1p/cputc.s

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;
; Ullrich von Bassewitz, 06.08.1998
;
; void cputcxy (unsigned char x, unsigned char y, char c);
; void cputc (char c);
;
.export _cputcxy, _cputc, cputdirect, putchar
.export newline, plot
.import popa, _gotoxy
.include "c1p.inc"
.include "extzp.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: cmp #$0A ; CR?
bne L1
lda #0
sta CURS_X
beq plot ; Recalculate pointers
L1: cmp #$0D ; LF?
beq newline ; Recalculate pointers
; Printable char of some sort
; cmp #' '
; bcc cputdirect ; Other control char < 0x20
; tay
; bmi L10
; cmp #$60
; bcc L2
; and #$DF
; bne cputdirect ; Branch always
;L2: and #$3F
cputdirect:
jsr putchar ; Write the character to the screen
; Advance cursor position
advance:
cpy SCR_LINELEN ; xsize-1
bne L3
jsr newline ; new line
ldy #$FF ; + cr
L3: iny
sty CURS_X
rts
newline:
lda SCR_LINELEN ; xsize-1
sec ; Account for -1 above
adc SCREEN_PTR
sta SCREEN_PTR
bcc L4
inc SCREEN_PTR+1
L4: inc CURS_Y
rts
; Handle character if high bit set
; L10: and #$7F
; cmp #$7E ; PI?
; bne L11
; lda #$5E ; Load screen code for PI
; bne cputdirect
; L11: ora #$40
; bne cputdirect
; Set cursor position, calculate RAM pointers
plot: ldy CURS_Y
lda ScrLo,y
sta SCREEN_PTR
lda ScrHi,y
; ldy SCR_LINELEN
; cpy #40+1
; bcc @L1
; asl SCREEN_PTR ; 80 column mode
; rol a
;@L1: ora #$80 ; Screen at $8000
sta SCREEN_PTR+1
rts
; Write one character to the screen without doing anything else, return X
; position in Y
putchar:
; ora RVS ; Set revers bit
ldy CURS_X
sta (SCREEN_PTR),y ; Set char
rts
; Screen address tables - offset to real screen
.rodata
ScrLo: .byte $83, $A3, $C3, $E3, $03, $23, $43, $63
.byte $83, $A3, $C3, $E3, $03, $23, $43, $63
.byte $83, $A3, $C3, $E3, $03, $23, $43, $63
.byte $83
ScrHi: .byte $D0, $D0, $D0, $D0, $D1, $D1, $D1, $D1
.byte $D1, $D1, $D1, $D1, $D2, $D2, $D2, $D2
.byte $D2, $D2, $D2, $D2, $D3, $D3, $D3, $D3
.byte $D3