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cc65/libsrc/cbm610/kplot.s
cuz 6d498d8187 Use external symbols for the CBM kernal jump table functions. This allows
to emulate these functions on platforms where one or more of these functions
are not available (PET, CBM-II).


git-svn-id: svn://svn.cc65.org/cc65/trunk@1544 b7a2c559-68d2-44c3-8de9-860c34a00d81
2002-11-19 23:02:47 +00:00

77 lines
1.2 KiB
ArmAsm

;
; Ullrich von Bassewitz, 28.09.1998
;
; PLOT routine for the 610.
;
.export PLOT
.importzp crtc
.include "cbm610.inc"
.proc PLOT
bcc set
ldx CURS_Y
ldy CURS_X
rts
set: stx CURS_Y
sty CURS_X
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 sedt1
lda CharPtr+1
adc #$00
and #$07
ora sedt1
sta (crtc),y
cli
pla
sta IndReg
rts
.endproc
; -------------------------------------------------------------------------
; 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