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cc65/libsrc/c64/cputc.s
uz d55fb5217e Changed the solution for the PLOT problem with old -02 kernals to that used
for the VIC20: PLOT is not an kernal entry but a library function that will 
do the right stuff. This makes it work with other stuff that calls PLOT, too.


git-svn-id: svn://svn.cc65.org/cc65/trunk@4249 b7a2c559-68d2-44c3-8de9-860c34a00d81
2009-09-27 18:45:08 +00:00

106 lines
1.8 KiB
ArmAsm

;
; Ullrich von Bassewitz, 1998-08-06, 2009-09-26
;
; void __fastcall__ cputcxy (unsigned char x, unsigned char y, char c);
; void __fastcall__ cputc (char c);
;
.export _cputcxy, _cputc, cputdirect, putchar
.export newline, plot
.import popa, _gotoxy
.import PLOT
.include "c64.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
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 SCREEN_PTR
sta SCREEN_PTR
bcc L4
inc SCREEN_PTR+1
clc
L4: lda #XSIZE
adc CRAM_PTR
sta CRAM_PTR
bcc L5
inc CRAM_PTR+1
L5: 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_X
ldx CURS_Y
clc
jmp PLOT ; Set the new cursor
; 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
lda CHARCOLOR
sta (CRAM_PTR),y ; Set color
rts