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----------------------------------------------------------------------
-- Typedefs and functions for clocks
-- www.fpgaarcade.com
-- All rights reserved.
--
-- admin@fpgaarcade.com
--
-- This Source Code Form is subject to the terms of the Mozilla Public
-- License, v. 2.0. If a copy of the MPL was not distributed with this
-- file, You can obtain one at https://mozilla.org/MPL/2.0/.
----------------------------------------------------------------------
library ieee;
use ieee.std_logic_1164.all;
package clock_functions_pack is
-----------------------------------------------------------------------------
-- Transparent handling of clock enables
--
-- Basic type def
type r_clk is record
base : std_logic;
val : std_logic;
rise : std_logic;
fall : std_logic;
end record;
constant z_clk : r_clk := (
base => '0',
val => '0',
rise => '0',
fall => '0');
-- Overloaded functions for synchronous process template
function rising_edge(signal clk : r_clk) return boolean;
function falling_edge(signal clk : r_clk) return boolean;
-- Overloaded functions for boolean arithmetic on clocks
function "not" (clk : r_clk) return r_clk;
--
function "and" (clk1, clk2 : r_clk) return r_clk;
function "and" (clk1 : r_clk; op2 : std_logic) return r_clk;
function "and" (op1 : std_logic; clk2 : r_clk) return std_logic;
--
function "nand" (clk1, clk2 : r_clk) return r_clk;
function "nand" (clk1 : r_clk; op2 : std_logic) return r_clk;
function "nand" (op1 : std_logic; clk2 : r_clk) return std_logic;
--
function "or" (clk1, clk2 : r_clk) return r_clk;
function "or" (clk1 : r_clk; op2 : std_logic) return r_clk;
function "or" (op1 : std_logic; clk2 : r_clk) return std_logic;
--
function "nor" (clk1, clk2 : r_clk) return r_clk;
function "nor" (clk1 : r_clk; op2 : std_logic) return r_clk;
function "nor" (op1 : std_logic; clk2 : r_clk) return std_logic;
--
function "=" (clk1 : r_clk; op2 : std_logic) return boolean;
end;
package body clock_functions_pack is
function rising_edge(signal clk : r_clk) return boolean is
begin
return rising_edge(clk.base) and clk.rise = '1';
end;
function falling_edge(signal clk : r_clk) return boolean is
begin
return rising_edge(clk.base) and clk.fall = '1';
end;
function "not" (clk : r_clk) return r_clk is
begin
return (base => clk.base,
val => not clk.val,
rise => clk.fall,
fall => clk.rise);
end;
function "and" (clk1, clk2 : r_clk) return r_clk is
begin
return (base => clk1.base,
val => clk1.val and clk2.val,
rise => (clk1.rise and clk2.val and not clk2.fall) or
(clk2.rise and clk1.val and not clk1.fall),
fall => (clk1.fall and clk2.val) or
(clk2.fall and clk1.val));
end;
function "and" (clk1 : r_clk; op2 : std_logic) return r_clk is
begin
return (base => clk1.base,
val => clk1.val and op2,
rise => clk1.rise and op2,
fall => clk1.fall and op2);
end;
function "and" (op1 : std_logic; clk2 : r_clk) return std_logic is
begin
return op1 and clk2.val;
end;
function "nand" (clk1, clk2 : r_clk) return r_clk is
begin
return (base => clk1.base,
val => clk1.val nand clk2.val,
rise => (clk1.fall and clk2.val) or
(clk2.fall and clk1.val),
fall => (clk1.rise and clk2.val and not clk2.fall) or
(clk2.rise and clk1.val and not clk1.fall));
end;
function "nand" (clk1 : r_clk; op2 : std_logic) return r_clk is
begin
return (base => clk1.base,
val => clk1.val nand op2,
rise => clk1.fall and op2,
fall => clk1.rise and op2);
end;
function "nand" (op1 : std_logic; clk2 : r_clk) return std_logic is
begin
return op1 nand clk2.val;
end;
function "or" (clk1, clk2 : r_clk) return r_clk is
begin
return (base => clk1.base,
val => clk1.val or clk2.val,
rise => (clk1.rise and not clk2.val) or
(clk2.rise and not clk1.val),
fall => (clk1.fall and not clk2.val and not clk2.rise) or
(clk2.fall and not clk1.val and not clk1.rise));
end;
function "or" (clk1 : r_clk; op2 : std_logic) return r_clk is
begin
return (base => clk1.base,
val => clk1.val or op2,
rise => clk1.rise and not op2,
fall => clk1.fall and not op2);
end;
function "or" (op1 : std_logic; clk2 : r_clk) return std_logic is
begin
return op1 or clk2.val;
end;
function "nor" (clk1, clk2 : r_clk) return r_clk is
begin
return (base => clk1.base,
val => clk1.val nor clk2.val,
rise => (clk1.fall and not clk2.val and not clk2.rise) or
(clk2.fall and not clk1.val and not clk1.rise),
fall => (clk1.rise and not clk2.val) or
(clk2.rise and not clk1.val));
end;
function "nor" (clk1 : r_clk; op2 : std_logic) return r_clk is
begin
return (base => clk1.base,
val => clk1.val nor op2,
rise => clk1.fall and not op2,
fall => clk1.rise and not op2);
end;
function "nor" (op1 : std_logic; clk2 : r_clk) return std_logic is
begin
return op1 nor clk2.val;
end;
function "=" (clk1 : r_clk; op2 : std_logic) return boolean is
begin
return clk1.val = op2;
end;
end;
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