Entity: arith_addw_xilinx

File: arith_addw_xilinx.vhdl

Diagram

Description

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Authors: Thomas B. Preusser

Entity: arith_addw_xilinx

Description:

Implements wide addition providing several options all based on an adaptation of a carry-select approach.
 Xilinx-specific optimizations.  References:     * Hong Diep Nguyen and Bogdan Pasca and Thomas B. Preusser:         FPGA-Specific Arithmetic Optimizations of Short-Latency Adders,         FPL 2011.         -> ARCH:     AAM, CAI, CCA         -> SKIPPING: CCC
     * Marcin Rogawski, Kris Gaj and Ekawat Homsirikamol:         A Novel Modular Adder for One Thousand Bits and More         Using Fast Carry Chains of Modern FPGAs, FPL 2014.         -> ARCH:         PAI         -> SKIPPING: PPN_KS, PPN_BK

License:

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and

limitations under the License.

Generics

Generic name	Type	Value	Description
N	positive		Operand Width
K	positive		Block Count
ARCH	tArch	CAI	Architecture
BLOCKING	tBlocking	DFLT	Blocking Scheme
SKIPPING	tSkipping	CCC	Carry Skip Scheme

Ports

Port name	Direction	Type
a	in	std_logic_vector(N-1 downto 0)
b	in	std_logic_vector(N-1 downto 0)
cin	in	std_logic
s	out	std_logic_vector(N-1 downto 0)
cout	out	std_logic

Signals

Name	Type	Description
g	std_logic_vector(K-1 downto 1)	Block Generate
p	std_logic_vector(K-1 downto 1)	Block Propagate
c	std_logic_vector(K-1 downto 1)

Constants

Name	Type	Value	Description
DEFAULT_BLOCKING	tBlocking_vector	(AAM => ASC, CAI => ASC, PAI => DESC, CCA => DESC)
BLOCKS	integer_vector(K-1 downto 0)	compute_blocks

Types

Name	Type	Description
tBlocking_vector
integer_vector	array(natural range<>) of integer

Functions

compute_blocks () return integer_vector