dattransf.vhd

基于VHDL的10位定点数转浮点数模块源代码

----------------------------------------------------------------------------------
-- Company:        uestc
-- Engineer:       hubiao
-- 
-- Create Date:    20:06:34 07/17/2007 
-- Design Name:    10bit two's complement to ieee 32 bit float digitals 
-- Module Name:    dattransf - transf 
-- Project Name:   2c2f
-- Target Devices: xc2v1500-6fg676c
-- Tool versions:  ise8.2i
-- Description:    10 bit two's complement's point is in afront;32bit float digitals is ieee standards
--
-- Dependencies: 
--
-- Revision: 
-- Revision 0.01 - File Created
-- Additional Comments: test pass successfully!!look up test.txt for more descriptions
--
----------------------------------------------------------------------------------
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

---- Uncomment the following library declaration if instantiating
---- any Xilinx primitives in this code.
--library UNISIM;
--use UNISIM.VComponents.all;

entity dattransf is
   port(datin : in bit_vector(9 downto 0);
	     clk:in std_logic;
		  ad_rst:in std_logic;
		  ad_buffer:out bit_vector(9 downto 0);
	     datout: out bit_vector(31 downto 0));
end dattransf;

architecture transf of dattransf is
  	
begin

 P1:process (datin,clk) 
      variable datbuf:bit_vector(9 downto 0);             
	   variable datfh:bit;                                  --IEEE32位浮点数标准:1位符号&8位指数&23位尾数
	   variable datwsh:bit_vector(22 downto 0);
	   variable datzsh:bit_vector(7 downto 0); 
		
	 begin
	 if ad_rst='1' then
	  if clk='0' and clk'event  then
       if datin(9)='0' then                                --第一步将2的补码数转换成有符号的绝对   
	       datbuf:=datin;
			 ad_buffer<=datbuf;
	    else
	       datbuf(9):=datin(9);                                 --负二进制补码取反码
	     	 datbuf(8):=not datin(8);
		    datbuf(7):=not datin(7);
          datbuf(6):=not datin(6);
		    datbuf(5):=not datin(5);
		    datbuf(4):=not datin(4);
		    datbuf(3):=not datin(3);
		    datbuf(2):=not datin(2);
		    datbuf(1):=not datin(1);
		    datbuf(0):=not datin(0);
		  if datbuf="1111111111" then
           datbuf:="1111111111";
        else			  
          if datbuf(0)='0' then			                        --反码加一得绝对值形式
             datbuf(0):='1';
			 else
			    datbuf(0):='0';
				 if datbuf(1)='0' then
				    datbuf(1):='1';
				 else
				    datbuf(1):='0';
					 if datbuf(2)='0' then
					    datbuf(2):='1';
					 else
					    datbuf(2):='0';
						 if datbuf(3)='0' then
						    datbuf(3):='1';
						 else 
						    datbuf(3):='0';
							 if datbuf(4)='0' then
							    datbuf(4):='1' ;
							 else
							    datbuf(4):='0';
								 if datbuf(5)='0' then
								    datbuf(5):='1';
								 else
								    datbuf(5):='0';
								    if datbuf(6)='0' then
									    datbuf(6):='1';
									 else
									    datbuf(6):='0';
										 if datbuf(7)='0' then
										    datbuf(7):='1';
										 else
										    datbuf(7):='0';
                                  if datbuf(8)='0' then
                                     datbuf(8):='1';
                                  else 
                                     datbuf(8):='0';
                                  end if;
                               end if;
                            end if;
                         end if;
                       end if;
                     end if;
                   end if;
                 end if;
               end if;
				 end if;
             ad_buffer<=datbuf;					
		  end if;
		  
		
		if datbuf(8)='1' then                                --
		   datwsh:=datbuf(7 downto 0)&"000000000000000";       
			datzsh:="01111110";                                  -- -1+2^7-1
		else
		   if datbuf(7)='1' then
			   datwsh:=datbuf(6 downto 0)&"0000000000000000";
			   datzsh:="01111101";                                -- -2+2^7-1 
			else
			   if datbuf(6)='1' then
				   datwsh:=datbuf(5 downto 0)&"00000000000000000";
				   datzsh:="01111100";                               -- -3+2^7-1 
				else
				   if datbuf(5)='1' then
					   datwsh:=datbuf(4 downto 0)&"000000000000000000";
					   datzsh:="01111011";                               -- -4+2^7-1 
					else 
					   if datbuf(4)='1' then
					      datwsh:=datbuf(3 downto 0)&"0000000000000000000";
					      datzsh:="01111010";                              -- -5+2^7-1 
						else
						   if datbuf(3)='1' then
							   datwsh:=datbuf(2 downto 0)&"00000000000000000000";
							   datzsh:="01111001";                             -- -6+2^7-1 
							else
							   if datbuf(2)='1' then 
								   datwsh:=datbuf(1 downto 0)&"000000000000000000000";
									datzsh:="01111000";                             -- -7+2^7-1 
								else
								   if datbuf(1)='1' then
									   datwsh:=datbuf(0)&"0000000000000000000000";
				                  datzsh:="01110111";                           -- -8+2^7-1 
									else
									   if datbuf(0)='1' then
										   datwsh:="00000000000000000000000";
											datzsh:="01110110";                          -- -9+2^7-1 
										else
										   datwsh:="00000000000000000000000";
											datzsh:="00000000";                          --定0，用IEEE32位标准表示浮点0
									   end if;
									end if;
								end if;
							end if;
						end if;
					end if;
				end if;
			end if;
		end if;
	  datfh:=datbuf(9);
     datout<=datfh & datzsh & datwsh;                        --第三步将datout
	 end if;
	  
	else
	  datfh:='0';
	  datzsh:="00000000";
	  datwsh:="00000000000000000000000";
	  datout<=datfh & datzsh & datwsh;
	end if;
	end process;
	
end transf;