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
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
encase
end
endmodule
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