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[/] [xmatchpro/] [trunk/] [xmw4-comdec/] [src/] [c_bs_counter_c.vhd] - Rev 9
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--This library is free software; you can redistribute it and/or --modify it under the terms of the GNU Lesser General Public --License as published by the Free Software Foundation; either --version 2.1 of the License, or (at your option) any later version. --This library is distributed in the hope that it will be useful, --but WITHOUT ANY WARRANTY; without even the implied warranty of --MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU --Lesser General Public License for more details. --You should have received a copy of the GNU Lesser General Public --License along with this library; if not, write to the Free Software --Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA -- e_mail : j.l.nunez-yanez@byacom.co.uk ---------------------------------------- -- ENTITY = C_BS_COUNTER -- -- version = 1.0 -- -- last update = 6/9/00 -- -- author = Jose Nunez -- ---------------------------------------- -- FUNCTION -- 16 bit counter to control the compressed block size -- PIN LIST -- LOAD = load compressed block size ( for decompression ) -- C_BS_IN = compressed block size external data ( for decompression ) -- ENABLE = enable count -- CLEAR = asyncronus clear of the counter -- CLK = master clock -- ALL_C_DATA = for decompression the value loaded has been reached -- C_BS_OUT = compressed block size available after compression library ieee,dzx; use ieee.std_logic_1164.all; use dzx.bit_arith.all; use dzx.bit_utils.all; entity C_BS_COUNTER_C is port ( COMPRESS : in bit; CLEAR_COUNTER : in bit; CLEAR : in bit; CLK : in bit; ENABLE_C : in bit; C_BS_OUT : out bit_vector(31 downto 0) ); end C_BS_COUNTER_C; architecture STRUCTURAL of C_BS_COUNTER_C is signal COUNT_AUX : bit_vector(29 downto 0); -- bytes signal COMPRESS_INT : bit; begin LATCH : process(CLK,CLEAR) begin -- asynchronous RESET signal forces all outputs LOW if (CLEAR = '0') then COMPRESS_INT <= '1'; -- check for +ve clock edge elsif ((CLK'event) and (CLK = '1')) then if(CLEAR_COUNTER = '0') then COMPRESS_INT <= '1'; elsif (COMPRESS = '0') then COMPRESS_INT <= '0'; else COMPRESS_INT <= COMPRESS_INT; end if; end if; end process LATCH; COUNTING : process (CLK,CLEAR,ENABLE_C,COMPRESS_INT,CLEAR_COUNTER) begin -- asynchronous RESET signal forces all outputs LOW if (CLEAR = '0') then COUNT_AUX <= "000000000000000000000000000000"; -- check for +ve clock edge elsif ((CLK'event) and (CLK = '1')) then if(CLEAR_COUNTER = '0') then COUNT_AUX <= "000000000000000000000000000000"; elsif( ENABLE_C = '0' and COMPRESS_INT = '0') then COUNT_AUX <= COUNT_AUX+"000000000000000000000000000001"; else COUNT_AUX <= COUNT_AUX; end if; end if; end process COUNTING; C_BS_OUT <= COUNT_AUX & "00"; -- bytes. always a multiple of 4 bytes. end STRUCTURAL;
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