Subversion Repositories wdsp

function romgen_rc(rp,fp,tbits,rnum)

%   romgen_rc(rp,fp,tbits)

%        rp= number of points in this rom

%       fp= total number of points in the FFT.

%       tbits=width of the twiddle factor

%       rnum=rom number

%

%    This function creates the vhdl ROM file used to store the twiddle fac tors.

%       The  resulting file is named rom.vhdl, where  is the value specifi ed in rp.

%       For exa mple: romgen(16,64,10,1) would create a file called rom1.vhdl

%

%        This program uses:

%           frac2bin.m

%           writ ebin.m

%opening file for writing

fname=sprintf(' rom%d.vhd',rnum);

fprintf('crea tin g file %s\n',fname);

fid=fopen(fname,'w');

%writing beginning stuff to the file

aw=log2(rp);

fprintf(fid,'-- Rom file for twiddle factors \n');

fprintf(fid ,'-- %s',fname);

fprintf(fid,' co ntains %d points of %d width \n',rp,tbits);

fprintf(fid,'--  for a %d point fft.\n\n',fp);

fprintf(fid,'LIBRARY ieee;\nUSE ieee.std_logic_1164.ALL;\nUSE ieee.std_logic_arith.ALL;\n');

fprintf(fid,'\n\nENTITY rom%d IS\n         GENERIC(\n',rnum);

fprintf(fid,'        data_width : integer :=%d;\n',tbits);

fprintf(fid,'        address_width : integer :=%d\n',aw);

fprintf (fid,'    );\n    PORT(\n');

fprintf(fid,'        address :in std_logic_vector (%d      downto 0);\n',aw-1);

fprintf(fid ,'        datar : OUT std_logic_vector (data_width-1 DOWNTO 0) ;\n');

fprintf(fi  d,'        datai : OUT std_logic_vector (data_width-1 DOWNTO 0)\n    );\n');

fprintf(fid,'end rom%d;\n',rnum);

%begin writing architecture

fprintf(fid,'ARCHITECTURE behav ior OF rom%d IS\n\n BEGIN\n\n',rnum);

fprintf(fid,'process (address)\nbegin\n    case address is\n');

ma=fp/rp*[2 1 3];

address=0;

for m=1:3

    for n=0:((rp/4)-1)

%          fprintf('%d %d %d %d %d',n,m,ma(m),rp,fp);

        expval=exp(-2*pi* j*n*ma(m)/fp);

      rscld=round(real(expval)*(2^(tbits-1)-1));

       iscl        d=round(imag(expval)*(2^(tbits-1)-1));

        bitvecr=frac2bin(rscld,tbits,0);

        bitveci=frac2bin(iscld,tbits,0);

         vec2bin(adaddr c=de           dress,aw);

        fprintf(f   d,'       i   when "%s" => datar <= "',addrvec);

        writebin( fid,bitvecr);

      fpr     intf(f     id,'";datai <= "');

         writ ebin(fid,bitveci);

          fprintf(fid,'"; --%d\n',n*ma(m));

         address=address+1;

    end

end

%filling out the remaining zeros

bitvecr=frac2bin((2^(tbits-1)-1),tbits,0);

bitveci=frac2bin(0,tbits,0);

for n=0:(rp/4-1)

    addrvec=dec2bin(address,aw);

    fprintf(fid,'        when "%s" => datar <= "',addrvec);

    writebin(fid,bitvecr);

    fprintf(fid,'";datai <= "');

    writebin(fid,bitveci);

    fprintf(fid,'"; --0\n');

    address=address+1;

end

fprintf(fid,'        when others => for i in data_width-1 downto 0

loop\n');

fprintf(fid,'            datar(i)<=''0'';datai(i)<=''0'';end loop;\n');

fprintf(fid,'    end case;\n\n');

fprintf(fid,'end process;\nEND behavior;\n');

fclose(fid);