add_sub_u2c.tdf

此程序是实现数字钟的

--lpm_add_sub CARRY_CHAIN=MANUAL CARRY_CHAIN_LENGTH=32 DEVICE_FAMILY=FLEX10K LPM_DIRECTION=SUB LPM_WIDTH=1 cout dataa datab result
--VERSION_BEGIN 4.0 cbx_lpm_add_sub 2003:11:17:16:32:08:SJ cbx_mgl 2004:01:13:14:00:54:SJ cbx_stratix 2003:12:15:10:23:28:SJ  VERSION_END


--  Copyright (C) 1988-2004 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
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--  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 1 
SUBDESIGN add_sub_u2c
( 
	cout	:	output;
	dataa[0..0]	:	input;
	datab[0..0]	:	input;
	result[0..0]	:	output;
) 
VARIABLE 
	add_sub_cella[0..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[0].sin = (! (dataa[0..0] $ (datab[0..0] $ main_cin_wire)));
	cout = add_sub_cella[0].cout;
	main_cin_wire = B"1";
	result[] = add_sub_cella[].sout;
END;
--VALID FILE