60 lines
1.6 KiB
Systemverilog
60 lines
1.6 KiB
Systemverilog
// Composite-like horizontal blending by Kitrinx
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// AMR - disable shift register recognition
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(* altera_attribute = "-name AUTO_SHIFT_REGISTER_RECOGNITION OFF" *)
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module cofi (
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input clk,
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input pix_ce,
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input enable,
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input hblank,
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input vblank,
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input hs,
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input vs,
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input [VIDEO_DEPTH-1:0] red,
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input [VIDEO_DEPTH-1:0] green,
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input [VIDEO_DEPTH-1:0] blue,
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output reg hblank_out,
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output reg vblank_out,
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output reg hs_out,
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output reg vs_out,
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output reg [VIDEO_DEPTH-1:0] red_out,
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output reg [VIDEO_DEPTH-1:0] green_out,
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output reg [VIDEO_DEPTH-1:0] blue_out
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);
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parameter VIDEO_DEPTH=8;
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function bit [VIDEO_DEPTH-1:0] color_blend (
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input [VIDEO_DEPTH-1:0] color_prev,
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input [VIDEO_DEPTH-1:0] color_curr,
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input blank_last
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);
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begin
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color_blend = blank_last ? color_curr : (color_prev >> 1) + (color_curr >> 1);
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end
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endfunction
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reg [VIDEO_DEPTH-1:0] red_last;
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reg [VIDEO_DEPTH-1:0] green_last;
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reg [VIDEO_DEPTH-1:0] blue_last;
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wire ce = enable ? pix_ce : 1'b1;
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always @(posedge clk) if (ce) begin
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hblank_out <= hblank;
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vblank_out <= vblank;
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vs_out <= vs;
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hs_out <= hs;
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red_last <= red;
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blue_last <= blue;
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green_last <= green;
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red_out <= enable ? color_blend(red_last, red, hblank_out) : red;
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blue_out <= enable ? color_blend(blue_last, blue, hblank_out) : blue;
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green_out <= enable ? color_blend(green_last, green, hblank_out) : green;
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end
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endmodule
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