add_sub_6dc.tdf

用vhdl语言实现的中值滤波,硬件需要DE2板

--lpm_add_sub CARRY_CHAIN="MANUAL" CARRY_CHAIN_LENGTH=48 DEVICE_FAMILY="Cyclone" LPM_DIRECTION="SUB" LPM_WIDTH=4 cout dataa datab result
--VERSION_BEGIN 4.2 cbx_cycloneii 2004:08:25:19:39:42:SJ cbx_lpm_add_sub 2004:10:25:10:56:48:SJ cbx_mgl 2004:10:26:10:32:18:SJ cbx_stratix 2004:09:23:18:28:34:SJ cbx_stratixii 2004:08:10:15:01:36:SJ  VERSION_END


--  Copyright (C) 1988-2002 Altera Corporation
--  Any  megafunction  design,  and related netlist (encrypted  or  decrypted),
--  support information,  device programming or simulation file,  and any other
--  associated  documentation or information  provided by  Altera  or a partner
--  under  Altera's   Megafunction   Partnership   Program  may  be  used  only
--  to program  PLD  devices (but not masked  PLD  devices) from  Altera.   Any
--  other  use  of such  megafunction  design,  netlist,  support  information,
--  device programming or simulation file,  or any other  related documentation
--  or information  is prohibited  for  any  other purpose,  including, but not
--  limited to  modification,  reverse engineering,  de-compiling, or use  with
--  any other  silicon devices,  unless such use is  explicitly  licensed under
--  a separate agreement with  Altera  or a megafunction partner.  Title to the
--  intellectual property,  including patents,  copyrights,  trademarks,  trade
--  secrets,  or maskworks,  embodied in any such megafunction design, netlist,
--  support  information,  device programming or simulation file,  or any other
--  related documentation or information provided by  Altera  or a megafunction
--  partner, remains with Altera, the megafunction partner, or their respective
--  licensors. No other licenses, including any licenses needed under any third
--  party's intellectual property, are provided herein.


FUNCTION carry_sum (cin, sin)
RETURNS ( cout, sout);

--synthesis_resources = lut 4 
SUBDESIGN add_sub_6dc
( 
	cout	:	output;
	dataa[3..0]	:	input;
	datab[3..0]	:	input;
	result[3..0]	:	output;
) 
VARIABLE 
	add_sub_cella[3..0] : carry_sum;
	main_cin_wire	: WIRE;

BEGIN 
	add_sub_cella[0].cin = (((! datab[0..0]) & main_cin_wire) # (dataa[0..0] & (! (datab[0..0] $ main_cin_wire))));
	add_sub_cella[1].cin = (((! datab[1..1]) & add_sub_cella[0].cout) # (dataa[1..1] & (! (datab[1..1] $ add_sub_cella[0].cout))));
	add_sub_cella[2].cin = (((! datab[2..2]) & add_sub_cella[1].cout) # (dataa[2..2] & (! (datab[2..2] $ add_sub_cella[1].cout))));
	add_sub_cella[3].cin = (((! datab[3..3]) & add_sub_cella[2].cout) # (dataa[3..3] & (! (datab[3..3] $ add_sub_cella[2].cout))));
	add_sub_cella[0].sin = (! (dataa[0..0] $ (datab[0..0] $ main_cin_wire)));
	add_sub_cella[1].sin = (! (dataa[1..1] $ (datab[1..1] $ add_sub_cella[0].cout)));
	add_sub_cella[2].sin = (! (dataa[2..2] $ (datab[2..2] $ add_sub_cella[1].cout)));
	add_sub_cella[3].sin = (! (dataa[3..3] $ (datab[3..3] $ add_sub_cella[2].cout)));
	cout = add_sub_cella[3].cout;
	main_cin_wire = B"1";
	result[] = add_sub_cella[].sout;
END;
--VALID FILE