fpga cordic

module Cordic(
    clk,
    rst_n,
    deg,
    sin,
    cos,
    finish
    );
    input clk;
    input rst_n;
    input signed [49:0]deg;//Q40 1符号位 9整数位
    output reg [31:0]sin;//Q31
    output reg [31:0]cos;
    output reg finish;
    reg signed [31:0]x;
    reg signed [31:0]y;
    reg signed [49:0]z;
    reg [3:0] quadrant;
    localparam signed [49:0]DEG90=50'h05a00000000a0; 
    localparam signed [49:0]DEG180=50'h0b40000000140;
    localparam signed [49:0]DEG270=50'h10dfffff860c0;
    localparam signed [49:0]DEG360=50'h1680000000280;
    localparam signed [32:0]KN=32'h4dba76d6;
    
    reg signed [49:0]deglis[15:0];
    always@(posedge clk)begin
    deglis[0]<=50'h02cffffff3d00;
    deglis[1]<=50'h01a90a7323be0;
    deglis[2]<=50'h00e09474070a0;
    deglis[3]<=50'h0072001123b80;
    deglis[4]<=50'h003938aa64bb0;
    deglis[5]<=50'h001ca3794f310;
    deglis[6]<=50'h000e52a1ab098;
    deglis[7]<=50'h0007296d7a290;
    deglis[8]<=50'h000394ba51d40;
    deglis[9]<=50'h0001ca5d9b6a8;
    deglis[10]<=50'h0000e52edc0a0;
    deglis[11]<=50'h000072976fd38;
    deglis[12]<=50'h0000394bb8220;
    deglis[13]<=50'h00001ca5dc16a;
    deglis[14]<=50'h00000e52ee0ce;
    deglis[15]<=50'h000007297706c;
    end
    //调整象限
    always@(*)begin
        if(!deg[49])begin
            if((deg>=0)&&(deg<DEG90))begin
                z=deg;
                quadrant=1;
                end
            else if((deg>=DEG90)&&(deg<DEG180))begin
                z=deg-DEG90;
                quadrant=2;
                end
            else if((deg>=DEG180)&&(deg<DEG270))begin     
                 z=DEG270-deg;
                 quadrant=3;
                 end
            else if((deg>=DEG270)&&(deg<DEG360))begin
                z=deg-DEG360;
                quadrant=4;
                end
        end
        else if(deg[49])begin
            if((deg[48:0]>=0)&&(deg[48:0]<DEG90[48:0]))begin
                z={1'b0,deg[48:0]};
                quadrant=4;
                end
            else if((deg[48:0]>=DEG90[48:0])&&(deg[48:0]<DEG180[48:0]))begin
                z={1'b0,deg[48:0]}-DEG90;
                quadrant=3;
                end
            else if((deg[48:0]>=DEG180[48:0])&&(deg[48:0]<DEG270[48:0]))begin     
                 z=DEG270-{1'b0,deg[48:0]};
                 quadrant=2;
                 end
            else if((deg[48:0]>=DEG270[48:0])&&(deg[48:0]<DEG360[48:0]))begin
                z={1'b0,deg[48:0]}-DEG360;
                quadrant=1;
                end
        end
    end
    
    reg [3:0] iter;
    always@(posedge clk or negedge rst_n)
    if(!rst_n)
        iter<=0;
    else if(!finish)
        iter<=iter+1;   
        
    always@(posedge clk or negedge rst_n)
    if(!rst_n)begin
        sin<=0;
        cos<=0;
        end
    else if(iter==15)begin
        case(quadrant)
        1:begin sin<=y;cos<=x;sin[31]<=0;cos[31]<=0;end
        2:begin cos<=y;sin<=x;sin[31]<=0;cos[31]<=1;end
        3:begin cos<=y;sin<=x;sin[31]<=1;cos[31]<=1;end
        4:begin sin<=y;cos<=x;sin[31]<=1;cos[31]<=0;end
        endcase
        end
        
    always@(posedge clk or negedge rst_n)
    if(!rst_n)
        finish<=0;
    else if(iter==15)
        finish<=1;
         
    always@(posedge clk or negedge rst_n)
    if(!rst_n)begin
        x<=KN;
        y<=0;
        end
    else if(!finish)
        if(z[49]==0)begin
            x<=x-(y>>>iter);
            y<=y+(x>>>iter);
            z<=z-deglis[iter];
            end
        else begin
            x<=x+(y>>>iter);
            y<=y-(x>>>iter);
            z<=z+deglis[iter];
            end 
    else begin
        x<=x;
        y<=y;
        z<=z;
        end
endmodule