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cc65/libsrc/cbm510/cputc.s
Oliver Schmidt 13482984ca Introduced internal gotoxy that pops both parameters.
About all CONIO functions offering a <...>xy variant call
  popa
  _gotoxy

By providing an internal gotoxy variant that starts with a popa all those CONIO function can be shortened by 3 bytes. As soon as program calls more than one CONIO function this means an overall code size reduction.
2016-06-05 14:58:38 +02:00

124 lines
3.0 KiB
ArmAsm

;
; Ullrich von Bassewitz, 14.09.2001
;
; void cputcxy (unsigned char x, unsigned char y, char c);
; void cputc (char c);
;
.export _cputcxy, _cputc, cputdirect, putchar
.export newline, plot
.import gotoxy
.import __VIDRAM_START__
.import CURS_X: zp, CURS_Y: zp, CHARCOLOR: zp, RVS: zp
.import SCREEN_PTR: zp, CRAM_PTR: zp
.include "cbm510.inc"
.macpack generic
; ------------------------------------------------------------------------
;
_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
; 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
; Move the cursor into the next line
newline:
inc CURS_Y
; Set cursor position, calculate RAM pointers
plot: ldx CURS_Y
lda LineLSBTab,x
sta SCREEN_PTR
sta CRAM_PTR
lda LineMSBTab,x
sta SCREEN_PTR+1
add #.hibyte(COLOR_RAM - __VIDRAM_START__)
sta CRAM_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
ldx IndReg
lda #$0F
sta IndReg
lda CHARCOLOR
sta (CRAM_PTR),y ; Set color
stx IndReg
rts
; -------------------------------------------------------------------------
; Low bytes of the start address of the screen lines
.rodata
LineLSBTab:
.repeat 25, I
.byte .lobyte(__VIDRAM_START__ + I * 40)
.endrep
; -------------------------------------------------------------------------
; High bytes of the start address of the screen lines
LineMSBTab:
.repeat 25, I
.byte .hibyte(__VIDRAM_START__ + I * 40)
.endrep