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Code: Select all

plotLine(x0,y0, x1,y1)
  dx=x1-x0
  dy=y1-y0

  D = 2*dy - dx
  plot(x0,y0)
  y=y0

  for x from x0+1 to x1
    if D > 0
      y = y+1
      plot(x,y)
      D = D + (2*dy-2*dx)
    else
      plot(x,y)
      D = D + (2*dy)

Code: Select all

module LineGen ( input clk,
					  output reg [9:0] X = 0,			
					  output reg [8:0] Y = 0			
					);
					
reg [9:0] x0;
reg [8:0] y0;
reg [9:0] x1;	
reg [8:0] y1;
reg [9:0] dx;
reg [8:0] dy;
reg [16:0] D;

reg [2:0] state;
parameter LOAD = 0, CALC1 = 1, CALC2 = 2, PLOT = 3;
				 
always @(posedge clk) begin
	state <= LOAD;

		case (state)
			LOAD:
				state <= CALC1;
				
			CALC1:
				state <= CALC2;
				
			CALC2:
				state <= PLOT;
					
			PLOT:
				if ( x0+1 <= x1 )
				state <= CALC2;
				else
				state <= LOAD;
		endcase
end

always @(posedge clk) begin
	case (state)
		LOAD:
		begin
			x0 <= 0;
			y0 <= 1;
			x1 <= 6;
			y1 <= 4;
		end

		CALC1:
		begin
			X <= x0;
			Y <= y0;
			dx <= x1 - x0;
			dy <= y1 - y0;
			D <= y1*2 - y0*2 - x1 + x0;
		end
	
		CALC2:
		if ( D[16] == 0 ) begin
				x0 <= x0 + 1;
				y0 <= y0 + 1;
				D <= D + dy*2 - dx*2;
			end
			else begin
				x0 <= x0 + 1;
				D <= D + dy*2;
			end
		
		PLOT:								
		begin
			X <= x0;
			Y <= y0;
		end
endcase

end

endmodule