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91 lines
1.4 KiB
Plaintext
91 lines
1.4 KiB
Plaintext
# Kernel
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# A Kernel draws a set of scanlines to the screen.
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component Kernel
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lines: 0..255 "Height of region in scanlines"
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bgcolor: 0..255 "Background color"
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end
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system SimpleKernel
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tempbytes 8
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on preframe do once [Kernel] ---
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lda #192 ; TODO: numlines
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sec
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sbc ypos_ypos_b0+ent
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sta {{$5}}+ofs
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ldy hasbitmap_bitmap_b0+ent
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lda bitmap_bitmapdata_b0,y
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sec
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sbc {{$5}}+ofs
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sta {{$0}}+ofs
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lda bitmap_bitmapdata_b8,y
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sbc #0
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sta {{$1}}+ofs
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ldy hascolormap_colormap_b0+ent
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lda colormap_colormapdata_b0,y
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sec
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sbc {{$5}}+ofs
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sta {{$2}}+ofs
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lda colormap_colormapdata_b8,y
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sbc #0
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sta {{$3}}+ofs
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lda sprite_height_b0+ent
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sta {{$4}}+ofs
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lda ypos_ypos_b0+ent
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sta {{$5}}+ofs
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---
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on preframe do once [Sprite,HasBitmap,HasColormap,HasYpos] --
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{{@KernelSetup}} 0,0
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{{@KernelSetup}} 1,6
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--
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on kernel do once [Kernel]:
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lda %{<bgcolor}
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sta COLUBK
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ldy %{<lines}
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@LVScan:
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lda %{$4} ; height
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dcp %{$5}
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bcs @DoDraw1
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lda #0
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.byte $2C
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@DoDraw1:
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lda (%{$0}),y
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sta WSYNC
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sta GRP0
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lda (%{$2}),y
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sta COLUP0
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lda %{$10} ; height
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dcp %{$11}
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bcs @DoDraw2
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lda #0
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.byte $2C
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@DoDraw2:
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lda (%{$6}),y
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sta GRP1
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lda (%{$8}),y
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sta COLUP1
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dey ; decrement
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bne @LVScan ; repeat until 192 lines
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--
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end
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scope Root
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entity kernel [SimpleKernel]
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const lines = 100
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end
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entity player1 [Sprite,HasBitmap,HasColormap,HasYpos]
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const plyrindex = 0
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init height = 8
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init xpos = 100
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init ypos = 100
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end
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end scope
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