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cc65/libsrc/cbm610/cputc.s
cuz a7042ddbe4 Complete redesign of the CBM610 support.
Use wrappers to call the kernal in bank 15 instead of implementing kernal
functionality within the cc65 libs (eats performance but is much smaller and
simpler).
Improved startup/shutdown code allows a return to the system bank without
calling the BASIC cold start vector.


git-svn-id: svn://svn.cc65.org/cc65/trunk@2793 b7a2c559-68d2-44c3-8de9-860c34a00d81
2003-12-20 23:13:26 +00:00

153 lines
2.8 KiB
ArmAsm

;
; 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 _gotoxy
.import popa
.import ktmp: zp, crtc: zp, CURS_X: zp, CURS_Y: zp, CharPtr: zp
.include "cbm610.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 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
; -------------------------------------------------------------------------
; 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