##// END OF EJS Templates
jro_hard » gen_acq
RSS
aaguilar - - Load All Authors

File last commit:

r214:215
r221:222
Show More
cic_utils.vhd
79 lines | 2.4 KiB | text/x-vhdl | VhdlLexer
/ trunk / firmware / sources / processingEngine / cic_utils.vhd
History | Annotation | Raw |Copy content |Copy permalink
library IEEE;
use IEEE.STD_LOGIC_1164.all;
use IEEE.numeric_std.all;
package cic_utils is
-- parametros de diseño del filtro CIC ----------------------------------------
constant MANTISSA_BITS : integer := 24;
constant NUMBER_BITS : integer := 32; -- incluye bit de signo
constant FIXWIDTH : integer := NUMBER_BITS + MANTISSA_BITS;
constant STAGES : integer := 5; -- orden del filtro CIC (numero de etapas)
-- no modificar ---------------------------------------------------------------
subtype fixpoint is std_logic_vector(FIXWIDTH-1 downto 0);
function "*"(a: std_logic_vector ; b: std_logic_vector) return std_logic_vector;
function "/"(a: std_logic_vector ; b: std_logic_vector) return std_logic_vector;
function "+"(a: std_logic_vector ; b: std_logic_vector) return std_logic_vector;
function "-"(a: std_logic_vector ; b: std_logic_vector) return std_logic_vector;
function to_fix(a: integer) return std_logic_vector;
constant MAX_M2_DEC : integer := 19;
constant ONE: integer := 2**MANTISSA_BITS;
end cic_utils;
package body cic_utils is
-- operaciones aritmeticas de punto fijo
function "*" ( a: std_logic_vector ; b: std_logic_vector)
return std_logic_vector is
variable ret : std_logic_vector(2*FIXWIDTH-1 downto 0);
begin
ret := std_logic_vector(signed(a)*signed(b));
return ret(a'length+MANTISSA_BITS-1 downto MANTISSA_BITS);
end "*";
function "/" (a: std_logic_vector ; b: std_logic_vector)
return std_logic_vector is
variable ret : std_logic_vector(a'length+MANTISSA_BITS-1 downto 0);
variable tmp : std_logic_vector(a'length+MANTISSA_BITS-1 downto 0):=(others=>'0');
begin
for i in 0 to a'length-1 loop
tmp(i+MANTISSA_BITS ) := a(i);
end loop;
ret := std_logic_vector(signed(tmp)/signed(b));
return ret(a'length-1 downto 0);
end "/";
function "+" (a: std_logic_vector ; b: std_logic_vector)
return std_logic_vector is
variable ret : std_logic_vector(a'length-1 downto 0);
begin
ret := std_logic_vector(signed(a)+signed(b));
return ret;
end "+";
function "-" (a: std_logic_vector ; b: std_logic_vector)
return std_logic_vector is
variable ret : std_logic_vector(a'length-1 downto 0);
begin
ret := std_logic_vector(signed(a)-signed(b));
return ret;
end "-";
--
function to_fix(a: integer)
return std_logic_vector is
variable ret : std_logic_vector(FIXWIDTH-1 downto 0);
begin
ret := std_logic_vector(to_signed(a,FIXWIDTH));
return ret;
end to_fix;
end cic_utils;