cyclecounter.vhd

文件ARM_core_VHDL.rar 嵌入式arm核的vhdl语言描述.

--****************************************************************************************************
-- Cycle counter for ARM core simualtion
-- Designed by Ruslan Lepetenok
-- Modified 17.01.2003
--****************************************************************************************************

library	IEEE;
use IEEE.std_logic_1164.all;
use IEEE.std_logic_unsigned.all;

use WORK.ARMPackage.all;

entity CycleCounter is port (
						   -- Global control signals
	                       nRESET    : in  std_logic;
						   CLK       : in  std_logic;
						   CLKEN     : in  std_logic;
						   -- Transaction type
						   TRANS     : in  std_logic_vector(1 downto 0)
   						    );
end CycleCounter;

architecture RTL of CycleCounter is
constant CycleCntWidth : positive := 32; 
signal CycleCnt : std_logic_vector (CycleCntWidth-1 downto 0) := (others => '0');

signal NCycleCnt : std_logic_vector (CycleCntWidth-1 downto 0) := (others => '0');
signal SCycleCnt : std_logic_vector (CycleCntWidth-1 downto 0) := (others => '0');
signal ICycleCnt : std_logic_vector (CycleCntWidth-1 downto 0) := (others => '0');
signal CCycleCnt : std_logic_vector (CycleCntWidth-1 downto 0) := (others => '0');

begin

CycleCounter:process(nRESET,CLK)
begin
if nRESET='0' then                          -- Reset
  CycleCnt  <= (others =>'0');
  ICycleCnt <= (others =>'0');
  NCycleCnt <= (others =>'0');
  SCycleCnt <= (others =>'0');
  CCycleCnt <= (others =>'0');

 elsif CLK='1' and CLK'event then           -- Clock
   if CLKEN='1' then                        -- Clock enable
    CycleCnt  <= CycleCnt+1;

   case TRANS is
   when CTT_I => ICycleCnt <= ICycleCnt+1; 
   when CTT_N => NCycleCnt <= NCycleCnt+1; 
   when CTT_S => SCycleCnt <= SCycleCnt+1; 
   when CTT_C => CCycleCnt <= CCycleCnt+1; 
   when others => null; 
   end case;	   
   
   end if;	
end if;
end process;			

end RTL;