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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
.destructor setsyscursor
.import gotoxy
.import PLOT
.import ktmp: zp, crtc: zp, CURS_X: zp, CURS_Y: zp, RVS: zp
.import CharPtr: zp
.include "cbm610.inc"
_cputcxy:
pha ; Save C
jsr gotoxy ; Set cursor, drop x and y
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
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:
iny
cpy #XSIZE
bne L3
jsr newline ; new line
ldy #0 ; + cr
L3: sty CURS_X
rts
newline:
clc
lda #XSIZE
adc CharPtr
sta CharPtr
bcc L4
inc CharPtr+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 ; Branch always
; Write one character to the screen without doing anything else, return X
; position in Y
putchar:
ldx IndReg
ldy #$0F
sty IndReg
ora RVS ; Set revers bit
ldy CURS_X
sta (CharPtr),y ; Set char
stx IndReg
rts
; Set cursor position, calculate RAM pointers
plot: ldx CURS_Y
lda LineLSBTab,x
sta CharPtr
lda LineMSBTab,x
sta CharPtr+1
lda IndReg
pha
lda #$0F
sta IndReg
ldy #$00
clc
sei
sta (crtc),y
lda CharPtr
adc CURS_X
iny
sta (crtc),y
dey
lda #$0E
sta (crtc),y
iny
lda (crtc),y
and #$F8
sta ktmp
lda CharPtr+1
adc #$00
and #$07
ora ktmp
sta (crtc),y
cli
pla
sta IndReg
rts
; -------------------------------------------------------------------------
; Cleanup routine that sets the kernal cursor position to ours
.segment "PAGE2"
setsyscursor:
ldy CURS_X
ldx CURS_Y
clc
jmp PLOT ; Set the new cursor
; -------------------------------------------------------------------------
; Low bytes of the start address of the screen lines
.rodata
LineLSBTab:
.byte $00,$50,$A0,$F0,$40,$90,$E0,$30
.byte $80,$D0,$20,$70,$C0,$10,$60,$B0
.byte $00,$50,$A0,$F0,$40,$90,$E0,$30
.byte $80
; -------------------------------------------------------------------------
; High bytes of the start address of the screen lines
LineMSBTab:
.byte $D0,$D0,$D0,$D0,$D1,$D1,$D1,$D2
.byte $D2,$D2,$D3,$D3,$D3,$D4,$D4,$D4
.byte $D5,$D5,$D5,$D5,$D6,$D6,$D6,$D7
.byte $D7
|
