float_synth.vhdl

something i got you may find this useful

      tmpcmd := to_slv (in2reg3 (in2reg3'low+2 downto in2reg3'low));
      case tmpcmd is
        when "000" =>
          outarray(0) := to_float(0, 8, 23);
        when "001" =>
          outarray(0) := to_float(0.0, 8, 23);
        when "010" =>
          outarray(0) := to_float(8, in1reg3);
        when "011" =>
          outarray(0) := to_float(8.0, in1reg3);
        when "100" =>
          outarray(0) := to_float(-8, 8, 23);
        when "101" =>
          outarray(0) := to_float(-8.0, 8, 23);
        when "110" =>
          outarray(0) := to_float(27000, in2reg3);
        when "111" =>
--          outarray(0) := "01000000010010010000111111011011";
          outarray(0) := to_float(MATH_PI, in2reg3);
        when others => null;
      end case;
    end if;

  end process cmd9reg;

  -- purpose: "1010" data manipulation (+, -, scalb, etc)
  cmd10reg: process (clk, rst_n) is
    variable tmpcmd : STD_LOGIC_VECTOR (2 downto 0);
    variable s : SIGNED (7 downto 0);  -- signed number
    variable outarray : cry_type;       -- array for output
    constant posinf : float32 := "01111111100000000000000000000000";  -- +inf
    constant neginf : float32 := "11111111100000000000000000000000";  -- +inf
    constant onept5 : float32 := "00111111110000000000000000000000";  -- 1.5
  begin  -- process cmd2reg

    if rst_n = '0' then                 -- asynchronous reset (active low)
      outx(10) <= ( others => '0');      
      jrloop: for j in 0 to 7 loop
        outarray (j) := (others => '0');
      end loop jrloop;
    elsif rising_edge(clk) then         -- rising clock edge
      outx(10) <= outarray(7);
      jcloop: for j in 7 downto 1 loop
        outarray (j) := outarray(j-1);
      end loop jcloop;
      tmpcmd := to_slv (in2reg3 (in2reg3'low+2 downto in2reg3'low));
      case tmpcmd is
        when "000" =>
          outarray(0) := - in1reg3;
        when "001" =>
          outarray(0) := abs( in1reg3);
        when "010" =>
          if (cmdarray(4) = "1010") then
            s := resize (SIGNED (to_slv (in2reg3(8 downto 5))), s'length);
            outarray(0) := Scalb (in1reg3, s);
          else
            outarray(0) := (others => '0');
          end if;
        when "011" =>
          if (cmdarray(4) = "1010") then
            s := logb (in1reg3);
            outarray(0) := (others => '0');
            outarray(0)(-16 downto -23) := float(std_logic_vector(s));
          else
            outarray(0) := (others => '0');
          end if;
        when "100" =>
          outarray(0) := Nextafter ( in1reg3, onept5);
        when "101" =>
          outarray(0) := Nextafter ( in1reg3, -onept5);
        when "110" =>
          outarray(0) := Nextafter ( x => in1reg3, y => posinf,
                                     check_error => false,
                                     denormalize => false);
        when "111" =>
          outarray(0) := Nextafter (x => in1reg3, y => neginf,
                                    check_error => false,
                                    denormalize => false);
        when others => null;
      end case;
    end if;

  end process cmd10reg;

  -- purpose "1011" copysign
  cmd11reg: process (clk, rst_n) is
    variable outarray : cry_type;       -- array for output
  begin  -- process cmd2reg
    if rst_n = '0' then                 -- asynchronous reset (active low)
      outx(11) <= ( others => '0');      
      jrloop: for j in 0 to 7 loop
        outarray (j) := (others => '0');
      end loop jrloop;
    elsif rising_edge(clk) then         -- rising clock edge
      outx(11) <= outarray(7);
      jcloop: for j in 7 downto 1 loop
        outarray (j) := outarray(j-1);
      end loop jcloop;
      outarray(0) := Copysign (in1reg3, in2reg3);
    end if;
  end process cmd11reg;

  -- purpose "1100" compare test
  cmd12reg: process (clk, rst_n) is
    variable outarray : cry_type;       -- array for output
    constant fifteenpt5 : float32 := "01000001011110000000000000000000";-- 15.5
  begin  -- process cmd2reg

    if rst_n = '0' then                 -- asynchronous reset (active low)
      outx(12) <= ( others => '0');      
      jrloop: for j in 0 to 7 loop
        outarray (j) := (others => '0');
      end loop jrloop;
    elsif rising_edge(clk) then         -- rising clock edge
      outx(12) <= outarray(7);
      jcloop: for j in 7 downto 1 loop
        outarray (j) := outarray(j-1);
      end loop jcloop;
      outarray(0) := (others => '0');
      if (in1reg3 = in2reg3) then
        outarray(0)(outarray(0)'high) := '1';
      else
        outarray(0)(outarray(0)'high) := '0';
      end if;
      if (in1reg3 /= in2reg3) then
        outarray(0)(outarray(0)'high-1) := '1';
      else
        outarray(0)(outarray(0)'high-1) := '0';
      end if;
      if (in1reg3 > in2reg3) then
        outarray(0)(outarray(0)'high-2) := '1';
      else
        outarray(0)(outarray(0)'high-2) := '0';
      end if;
      if (in1reg3 < in2reg3) then
        outarray(0)(outarray(0)'high-3) := '1';
      else
        outarray(0)(outarray(0)'high-3) := '0';
      end if;
      if (in1reg3 >= in2reg3) then
        outarray(0)(outarray(0)'high-4) := '1';
      else
        outarray(0)(outarray(0)'high-4) := '0';
      end if;
      if (in1reg3 <= in2reg3) then
        outarray(0)(outarray(0)'high-5) := '1';
      else
        outarray(0)(outarray(0)'high-5) := '0';
      end if;
      outarray(0)(outarray(0)'high-6) := \?=\ (in1reg3, 15);
      outarray(0)(outarray(0)'high-7) := \?=\ (in1reg3, 15.5);
      if (Unordered (in1reg3, in2reg3)) then
        outarray(0)(outarray(0)'high-8) := '1';
      else
        outarray(0)(outarray(0)'high-8) := '0';        
      end if;
      if (Finite (in1reg3)) then
        outarray(0)(outarray(0)'high-9) := '1';
      else
        outarray(0)(outarray(0)'high-9) := '0';        
      end if;
      if (Isnan (in1reg3)) then
        outarray(0)(outarray(0)'high-10) := '1';
      else
        outarray(0)(outarray(0)'high-10) := '0';        
      end if;
    end if;

  end process cmd12reg;

  -- purpose "1101" boolean test
  cmd13reg: process (clk, rst_n) is
    variable tmpcmd : STD_LOGIC_VECTOR (2 downto 0);
    variable outarray : cry_type;       -- array for output
  begin  -- process cmd2reg

    if rst_n = '0' then                 -- asynchronous reset (active low)
      outx(13) <= ( others => '0');      
      jrloop: for j in 0 to 7 loop
        outarray (j) := (others => '0');
      end loop jrloop;
    elsif rising_edge(clk) then         -- rising clock edge
      outx(13) <= outarray(7);
      jcloop: for j in 7 downto 1 loop
        outarray (j) := outarray(j-1);
      end loop jcloop;
      tmpcmd := to_slv (in2reg3 (in2reg3'low+2 downto in2reg3'low));
      case tmpcmd is
        when "000" =>
          outarray(0) := not (in1reg3);
        when "001" =>
          outarray(0) := in1reg3 and in2reg3;
        when "010" =>
          outarray(0) := in1reg3 or in2reg3;
        when "011" =>
          outarray(0) := in1reg3 nand in2reg3;
        when "100" =>
          outarray(0) := in1reg3 nor in2reg3;
        when "101" =>
          outarray(0) := in1reg3 xor in2reg3;
        when "110" =>
          outarray(0) := in1reg3 xnor in2reg3;
        when "111" =>
          outarray(0) := in1reg3 xor '1';
        when others => null;
      end case;
    end if;

  end process cmd13reg;

  -- purpose "1110" reduce and vector test
  cmd14reg: process (clk, rst_n) is
    variable tmpcmd : STD_LOGIC_VECTOR (2 downto 0);
    variable outarray : cry_type;       -- array for output
  begin  -- process cmd2reg

    if rst_n = '0' then                 -- asynchronous reset (active low)
      outx(14) <= ( others => '0');      
      jrloop: for j in 0 to 7 loop
        outarray (j) := (others => '0');
      end loop jrloop;
    elsif rising_edge(clk) then         -- rising clock edge
      outx(14) <= outarray(7);
      jcloop: for j in 7 downto 1 loop
        outarray (j) := outarray(j-1);
      end loop jcloop;
      tmpcmd := to_slv (in2reg3 (in2reg3'low+2 downto in2reg3'low));
      case tmpcmd is
        when "000" =>
          outarray(0) := (others => '0');
          outarray(0)(outarray(0)'high) := and_reduce (in1reg3);
          outarray(0)(outarray(0)'high-1) := nand_reduce (in1reg3);
          outarray(0)(outarray(0)'high-2) := or_reduce (in1reg3);
          outarray(0)(outarray(0)'high-3) := nor_reduce (in1reg3);
          outarray(0)(outarray(0)'high-4) := xor_reduce (in1reg3);
          outarray(0)(outarray(0)'high-5) := xnor_reduce (in1reg3);
        when "001" => 
          outarray(0) := in1reg3 and in2reg3(in2reg3'high);
        when "010" => 
          outarray(0) := in1reg3 or in2reg3(in2reg3'high);
        when "011" => 
          outarray(0) := in1reg3 nand in2reg3(in2reg3'high);
        when "100" => 
          outarray(0) := in1reg3 nor in2reg3(in2reg3'high);
        when "101" => 
          outarray(0) := in2reg3(in2reg3'high) xor in1reg3;
        when "110" => 
          outarray(0) := in2reg3(in2reg3'high) xnor in1reg3;
        when "111" => 
          outarray(0) := in2reg3(in2reg3'high) and in1reg3;
        when others => null;
      end case;
    end if;

  end process cmd14reg;

  -- purpose "1111"  + constant
  cmd15reg: process (clk, rst_n) is
    variable tmpcmd : STD_LOGIC_VECTOR (2 downto 0);
    variable outarray : cry_type;       -- array for output
  begin  -- process cmd2reg

    if rst_n = '0' then                 -- asynchronous reset (active low)
      outx(15) <= ( others => '0');      
      jrloop: for j in 0 to 7 loop
        outarray (j) := (others => '0');
      end loop jrloop;
    elsif rising_edge(clk) then         -- rising clock edge
      outx(15) <= outarray(7);
      jcloop: for j in 7 downto 1 loop
        outarray (j) := outarray(j-1);
      end loop jcloop;
      tmpcmd := to_slv (in2reg3 (in2reg3'low+2 downto in2reg3'low));
      case tmpcmd is
        when "000" =>
          outarray(0) := in1reg3 + 1;
        when "001" =>
          outarray(0) := 1 + in1reg3;
        when "010" =>
          outarray(0) := in1reg3 + 1.0;
        when "011" =>
          outarray(0) := 1.0 + in1reg3;
        when "100" =>
          outarray(0) := in1reg3 * 1;
        when "101" =>
          outarray(0) := 1 * in1reg3;
        when "110" =>
          outarray(0) := in1reg3 * 1.0;
        when "111" =>
          outarray(0) := 1.0 * in1reg3;
        when others => null;
      end case;
    end if;

  end process cmd15reg;
  
  -- purpose: multiply floating point
  -- type   : sequential
  -- inputs : clk, rst_n, in1, in2
  -- outputs: out1
  cmdreg: process (clk, rst_n) is
    variable  outreg : float32;  -- register stages
    variable in1reg, in2reg : float32;  -- register stages
    variable in1reg2, in2reg2 : float32;  -- register stages
  begin  -- process mulreg

    if rst_n = '0' then                 -- asynchronous reset (active low)
      in1reg := ( others => '0');
      in2reg := ( others => '0');
      in1reg2 := ( others => '0');
      in2reg2 := ( others => '0');
      in1reg3 <= ( others => '0');
      in2reg3 <= ( others => '0');
      out1 <= ( others => '0');
      outreg := (others => '0');
      rcloop: for i in 1 to 15 loop
        cmdarray (i) <= (others => '0');
      end loop rcloop;
    elsif rising_edge(clk) then         -- rising clock edge
      out1 <= to_slv (outreg);
      outregc: case cmdarray (13) is
        when "0000" => outreg := outx (0);
        when "0001" => outreg := outx (1);
        when "0010" => outreg := outx (2);
        when "0011" => outreg := outx (3);
        when "0100" => outreg := outx (4);
        when "0101" => outreg := outx (5);
        when "0110" => outreg := outx (6);
        when "0111" => outreg := outx (7);
        when "1000" => outreg := outx (8);
        when "1001" => outreg := outx (9);
        when "1010" => outreg := outx (10);
        when "1011" => outreg := outx (11);
        when "1100" => outreg := outx (12);
        when "1101" => outreg := outx (13);
        when "1110" => outreg := outx (14);
        when "1111" => outreg := outx (15);
        when others => null;
      end case outregc;
      cmdpipe: for i in 15 downto 3 loop
        cmdarray (i) <= cmdarray (i-1);
      end loop cmdpipe;
      cmdarray (2) <= std_ulogic_vector(cmd);
      in1reg3 <= in1reg2;
      in2reg3 <= in2reg2;
      in1reg2 := in1reg;
      in2reg2 := in2reg;
      in1reg := to_float (in1, in1reg);
      in2reg := to_float (in2, in2reg);
    end if;

  end process cmdreg;

end architecture rtl;