cordic_3.v

流水线结构的cordic

module cordic (clk,rst_n,ena,phase_in,sin_out,cos_out,eps);

parameter DATA_WIDTH=8;
parameter PIPELINE=8;

input     clk;
input     rst_n;
input     ena;
input  [DATA_WIDTH-1:0]	 phase_in;

output [DATA_WIDTH-1:0]  sin_out;  
output [DATA_WIDTH-1:0]  cos_out;
output [DATA_WIDTH-1:0]  eps;

reg    [DATA_WIDTH-1:0]  sin_out;
reg    [DATA_WIDTH-1:0]  cos_out;
reg    [DATA_WIDTH-1:0]  eps;

reg    [DATA_WIDTH-1:0]  phase_in_reg;

reg	   [DATA_WIDTH-1:0]	 x0,y0,z0;
reg	   [DATA_WIDTH-1:0]  x1,y1,z1;
reg	   [DATA_WIDTH-1:0]  x2,y2,z2;
reg	   [DATA_WIDTH-1:0]  x3,y3,z3;
reg	   [DATA_WIDTH-1:0]  x4,y4,z4;
reg	   [DATA_WIDTH-1:0]  x5,y5,z5;
reg	   [DATA_WIDTH-1:0]  x6,y6,z6;
reg	   [DATA_WIDTH-1:0]  x7,y7,z7;

reg	   [1:0]			 quadrant[PIPELINE:0];

integer i;

//get real quadrant and map to first_n quadrant

always@(posedge clk or negedge rst_n)
begin
	if(!rst_n)
		phase_in_reg<=8'b0000_0000;
	else
		if(ena)
			begin
				case(phase_in[7:6])
					2'b00:phase_in_reg<=phase_in;
					2'b01:phase_in_reg<=phase_in-8'h40;  //-pi/2
					2'b10:phase_in_reg<=phase_in-8'h80;  //-pi
					2'b11:phase_in_reg<=phase_in-8'hc0;  //-3pi/2
					default:;
				 endcase
			 end
end

always@(posedge clk or negedge rst_n)
begin
	if(!rst_n)
		begin
			x0<=8'b0000_0000;
			y0<=8'b0000_0000;
			z0<=8'b0000_0000;
		end
	 else
		if(ena)
			begin
				x0<=8'h4D;  //define aggregate constant Xi=1/P=1/1.6467=0.60725 (Xi=2^7*P+8'h4D)
				y0<=8'h00;
				z0<=phase_in_reg;
			end
end

//level 1
always@(posedge clk or negedge rst_n)
begin
	if(!rst_n)
		begin
			x1<=8'b0000_0000;
			y1<=8'b0000_0000;
			z1<=8'b0000_0000;
		end
	 else
	 	if(ena)
			if(z0[7]==1'b0)
				begin
					x1<=x0-y0;
					y1<=y0+x0;
					z1<=z0-8'h20;  //45deg
				end
		else
			begin
					x1<=x0+y0;
					y1<=y0-x0;
					z1<=z0+8'h20;  //45deg	
		end	
end

//level 2
always@(posedge clk or negedge rst_n)
begin
	if(!rst_n)
		begin
			x2<=8'b0000_0000;
			y2<=8'b0000_0000;
			z2<=8'b0000_0000;
		end
	 else
	 	if(ena)
			if(z1[7]==1'b0)
				begin
					x2<=x1-{y1[DATA_WIDTH-1],y1[DATA_WIDTH-1:1]};
					y2<=y1+{x1[DATA_WIDTH-1],x1[DATA_WIDTH-1:1]};
					z2<=z1-8'h12;  //26deg
				end
			 else
				begin
					x2<=x1+{y1[DATA_WIDTH-1],y1[DATA_WIDTH-1:1]};
					y2<=y1-{x1[DATA_WIDTH-1],x1[DATA_WIDTH-1:1]};
					z2<=z1+8'h12;
				end
end

//level 3  
always@(posedge clk or negedge rst_n)
begin
	if(!rst_n)
		begin
			x3<=8'b0000_0000;
			y3<=8'b0000_0000;
			z3<=8'b0000_0000;
		end
	 else
	 	if(ena)
			if(z2[7]==1'b0)
				begin
					x3<=x2-{{2{y2[DATA_WIDTH-1]}},y2[DATA_WIDTH-1:2]};
					y3<=y2+{{2{x2[DATA_WIDTH-1]}},x2[DATA_WIDTH-1:2]};
					z3<=z2-8'h09;  //14deg
				end
			 else
				begin
					x3<=x2+{{2{y2[DATA_WIDTH-1]}},y2[DATA_WIDTH-1:2]};
					y3<=y2-{{2{x2[DATA_WIDTH-1]}},x2[DATA_WIDTH-1:2]};
					z3<=z2+8'h09;
				end
end

//level 4
always@(posedge clk or negedge rst_n)
begin
	if(!rst_n)
		begin
			x4<=8'b0000_0000;
			y4<=8'b0000_0000;
			z4<=8'b0000_0000;
		end
	 else
	 	if(ena)
			if(z3[7]==1'b0)
				begin
					x4<=x3-{{3{y3[DATA_WIDTH-1]}},y3[DATA_WIDTH-1:3]};
					y4<=y3+{{3{x3[DATA_WIDTH-1]}},x3[DATA_WIDTH-1:3]};
					z4<=z3-8'h04;  //7deg
				end
			 else
				begin
					x4<=x3+{{3{y3[DATA_WIDTH-1]}},y3[DATA_WIDTH-1:3]};
					y4<=y3-{{3{x3[DATA_WIDTH-1]}},x3[DATA_WIDTH-1:3]};
					z4<=z3+8'h04;
				end
end

//level 5
always@(posedge clk or negedge rst_n)
begin
	if(!rst_n)
		begin
			x5<=8'b0000_0000;
			y5<=8'b0000_0000;
			z5<=8'b0000_0000;
		end
	 else
	 	if(ena)
			if(z4[7]==1'b0)
				begin
					x5<=x4-{{4{y4[DATA_WIDTH-1]}},y4[DATA_WIDTH-1:4]};
					y5<=y4+{{4{x4[DATA_WIDTH-1]}},x4[DATA_WIDTH-1:4]};
					z5<=z4-8'h02;  //4deg
				end
			 else
				begin
					x5<=x4+{{4{y4[DATA_WIDTH-1]}},y4[DATA_WIDTH-1:4]};
					y5<=y4-{{4{x4[DATA_WIDTH-1]}},x4[DATA_WIDTH-1:4]};
					z5<=z4+8'h02;
				end
end

//level 6
always@(posedge clk or negedge rst_n)
begin
	if(!rst_n)
		begin
			x6<=8'b0000_0000;
			y6<=8'b0000_0000;
			z6<=8'b0000_0000;
		end
	 else
	 	if(ena)
			if(z5[7]==1'b0)
				begin
					x6<=x5-{{5{y5[DATA_WIDTH-1]}},y5[DATA_WIDTH-1:5]};
					y6<=y5+{{5{x5[DATA_WIDTH-1]}},x5[DATA_WIDTH-1:5]};
					z6<=z5-8'h01;  //2deg
				end
			 else
				begin
					x6<=x5+{{5{y5[DATA_WIDTH-1]}},y5[DATA_WIDTH-1:5]};
					y6<=y5-{{5{x5[DATA_WIDTH-1]}},x5[DATA_WIDTH-1:5]};
					z6<=z5+8'h01;
				end
end

//level 7
always@(posedge clk or negedge rst_n)
begin
	if(!rst_n)
		begin
			x7<=8'b0000_0000;
			y7<=8'b0000_0000;
			z7<=8'b0000_0000;
		end
	 else
	 	if(ena)
			if(z6[7]==1'b0)
				begin
					x7<=x6-{{6{y6[DATA_WIDTH-1]}},y6[DATA_WIDTH-1:6]};
					y7<=y6+{{6{x6[DATA_WIDTH-1]}},x6[DATA_WIDTH-1:6]};
					z7<=z6-8'h00;  //1deg
				end
			 else
				begin
					x7<=x6+{{6{y6[DATA_WIDTH-1]}},y6[DATA_WIDTH-1:6]};
					y7<=y6-{{6{x6[DATA_WIDTH-1]}},x6[DATA_WIDTH-1:6]};
					z7<=z6+8'h00;
				end
end

//remain the quadrant information for "duiqi"
always@(posedge clk or negedge rst_n)
begin
	if(!rst_n)
		for(i=0;i<=PIPELINE;i=i+1)
			quadrant[i]<=2'b00;
	else
		if(ena)
			begin
				for(i=0;i<PIPELINE;i=i+1)
					quadrant[i+1]<=quadrant[i];
					quadrant[0]<=phase_in[7:6];
			end
end

always@(posedge clk or negedge rst_n)
begin
	if(!rst_n)
		begin
			sin_out<=8'b0000_0000;
			cos_out<=8'b0000_0000;
			eps    <=8'b0000_0000;
		end
	 else
		if(ena)
			case(quadrant[7])
				2'b00:begin
			    	sin_out<=y6;
					cos_out<=x6;
					eps    <=z6;
				   end
				2'b01:begin
					sin_out<=x6;
					cos_out<=~(y6)+1'b1;
					eps    <=z6;
				   end
				2'b10:begin
					sin_out<=~(y6)+1'b1;
					cos_out<=~(x6)+1'b1;
					eps    <=z6;
				   end	
				2'b11:begin
					sin_out<=~(x6)+1'b1;
					cos_out<=y6;
					eps    <=z6;
				   end
			  endcase
end

endmodule