ADDSUB_MACRO - 2024.1 English

Macro: Adder/Subtracter

Introduction

ADDSUB_MACRO simplifies the instantiation of the DSP48 block when used as a simple adder/subtracter. It features parameterizable input and output widths and latency that ease the integration of the DSP48 block into HDL.

Port Descriptions

Port	Direction	Width	Function
CARRYOUT	Output	1	Carry Out
RESULT	Output	Variable, see WIDTH attribute.	Data output bus addressed by RDADDR.
ADDSUB	Input	1	When high, RESULT is an addition. When low, RESULT is a subtraction.
A	Input	Variable, see WIDTH attribute.	Data input to add/sub.
B	Input	Variable, see WIDTH attribute.	Data input to add/sub.
CE	Input	1	Clock Enable.
CARRYIN	Input	1	Carry In.
CLK	Input	1	Clock.
RST	Input	1	Synchronous Reset.

Design Entry Method

This unimacro is a parameterizable version of the primitive, and can be instantiated only.

Instantiation	Yes
Inference	No
IP Catalog	No
Macro support	Recommended

Available Attributes

Attribute	Type	Allowed Values	Default	Description
DEVICE	STRING	"7SERIES"	"7SERIES"	Target hardware architecture.
LATENCY	INTEGER	0, 1, 2	2	Number of pipeline registers. 1: PREG == 1 2: AREG == BREG == CREG == PREG
WIDTH	INTEGER	1-48	48	Result port width override.

VHDL Instantiation Template

Unless they already exist, copy the following four statements and paste them before the entity declaration.

Library UNISIM;
use UNISIM.vcomponents.all;
library UNIMACRO;
use unimacro.Vcomponents.all;


-- ADDSUB_MACRO: Variable width & latency - Adder / Subtrator implemented in a DSP48E
--               7 Series
-- Xilinx HDL Language Template, version 2024.1

ADDSUB_MACRO_inst : ADDSUB_MACRO
generic map (
   DEVICE => "7SERIES", -- Target Device: "VIRTEX5", "7SERIES", "SPARTAN6"
   LATENCY => 2,        -- Desired clock cycle latency, 0-2
   WIDTH => 48)         -- Input / Output bus width, 1-48
port map (
   CARRYOUT => CARRYOUT, -- 1-bit carry-out output signal
   RESULT => RESULT,     -- Add/sub result output, width defined by WIDTH generic
   A => A,               -- Input A bus, width defined by WIDTH generic
   ADD_SUB => ADD_SUB,   -- 1-bit add/sub input, high selects add, low selects subtract
   B => B,               -- Input B bus, width defined by WIDTH generic
   CARRYIN => CARRYIN,   -- 1-bit carry-in input
   CE => CE,             -- 1-bit clock enable input
   CLK =>CLK,           -- 1-bit clock input
   RST => RST            -- 1-bit active high synchronous reset
);
-- End of ADDSUB_MACRO_inst instantiation

Verilog Instantiation Template


// ADDSUB_MACRO: Variable width & latency - Adder / Subtracter implemented in a DSP48E
//               7 Series
// Xilinx HDL Language Template, version 2024.1

ADDSUB_MACRO #(
   .DEVICE("7SERIES"), // Target Device: "7SERIES"
   .LATENCY(2),        // Desired clock cycle latency, 0-2
   .WIDTH(48)          // Input / output bus width, 1-48
) ADDSUB_MACRO_inst (
   .CARRYOUT(CARRYOUT), // 1-bit carry-out output signal
   .RESULT(RESULT),     // Add/sub result output, width defined by WIDTH parameter
   .A(A),               // Input A bus, width defined by WIDTH parameter
   .ADD_SUB(ADD_SUB),   // 1-bit add/sub input, high selects add, low selects subtract
   .B(B),               // Input B bus, width defined by WIDTH parameter
   .CARRYIN(CARRYIN),   // 1-bit carry-in input
   .CE(CE),             // 1-bit clock enable input
   .CLK(CLK),           // 1-bit clock input
   .RST(RST)            // 1-bit active high synchronous reset
);

// End of ADDSUB_MACRO_inst instantiation