add_sub_4rh.tdf

用vhdl语言编写的基于FPGA的波形发生器。对于做实验需要产生的波形非常有用。

--lpm_add_sub CARRY_CHAIN="MANUAL" CARRY_CHAIN_LENGTH=48 DEVICE_FAMILY="Cyclone" LPM_DIRECTION="ADD" LPM_REPRESENTATION="UNSIGNED" LPM_WIDTH=4 ONE_INPUT_IS_CONSTANT="YES" cin dataa datab result
--VERSION_BEGIN 5.1 cbx_cycloneii 2005:12:13:10:36:54:SJ cbx_lpm_add_sub 2005:11:02:10:42:42:SJ cbx_mgl 2006:01:12:16:15:18:SJ cbx_stratix 2005:12:28:11:18:26:SJ cbx_stratixii 2005:11:02:10:43:56:SJ  VERSION_END


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

--synthesis_resources = lut 5 
SUBDESIGN add_sub_4rh
( 
	cin	:	input;
	dataa[3..0]	:	input;
	datab[3..0]	:	input;
	result[3..0]	:	output;
) 
VARIABLE 
	add_sub_cella[3..0] : carry_sum;
	external_cin_cell : carry_sum;
	datab_node[3..0]	: WIRE;
	main_cin_wire	: WIRE;

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