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65 lines
1.3 KiB
ArmAsm
65 lines
1.3 KiB
ArmAsm
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.export soft80_kplot
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.include "c64.inc"
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.include "soft80.inc"
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soft80_kplot:
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bcs @getpos
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stx CURS_Y
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sty CURS_X
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; calc pointer to bitmap
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lda _bitmaplo,x
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clc
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adc _bitmapxlo,y
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sta SCREEN_PTR
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lda _bitmaphi,x
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adc _bitmapxhi,y
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sta SCREEN_PTR+1
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; calc pointer to vram
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tya
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lsr a ; NOTE: we can save 2 cycles here at the expense of
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; making the tables twice as big (+50 bytes)
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clc
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adc _vramlo,x
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sta CRAM_PTR
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lda #0
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adc _vramhi,x
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sta CRAM_PTR+1
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@getpos:
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ldx CURS_Y
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ldy CURS_X
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rts
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.rodata
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_bitmapxlo:
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.repeat 80,col
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.byte <((col/2)*8)
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.endrepeat
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_bitmapxhi:
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.repeat 80,col
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.byte >((col/2)*8)
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.endrepeat
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_vramlo:
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.repeat 25,row
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.byte <(soft80_vram+(row*40))
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.endrepeat
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_vramhi:
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.repeat 25,row
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.byte >(soft80_vram+(row*40))
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.endrepeat
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_bitmaplo:
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.repeat 25,row
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.byte <(soft80_bitmap+(row*40*8))
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.endrepeat
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_bitmaphi:
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.repeat 25,row
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.byte >(soft80_bitmap+(row*40*8))
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.endrepeat
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