Bit Shift

R2026b

Logical or arithmetic shift of input signal

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Bit Shift block

To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.

Libraries:
HDL Coder / Logic and Bit Operations

Description

The Bit Shift block performs a logical or arithmetic shift on the input signal.

This block is different from the Shift Arithmetic block in terms of simulation and HDL code generation behavior. The Bit Shift block can perform logical shifting of a signed number without having to perform a reinterpretcast operation. This block uses a MATLAB Function block based implementation and might be slower in operation.

The Shift Arithmetic block shifts the bits or binary point of the input number. This block has additional block options for HDL code generation in comparison to the Bit Shift block. When you want to perform a variable shift operation, use the Shift Arithmetic block instead of the Bit Shift block. If you have a signed number as input, the block performs a sign extension of the number. The Shift Arithmetic block requires using additional Data Type Conversion blocks that have the Stored Integer (SI) option selected.

Ports

Input

Port_1 — Input Signal

scalar | vector

Input signal on which the logical or arithmetic shift is performed.

• Minimum bit width: 2

• Maximum bit width: 128

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | Boolean | fixed point

Output

Port_1 — Output Signal

scalar | vector

Output signal that is logically or arithmetically shifted. The output signal has the same data type and bit width as the input signal.

• Minimum bit width: 2

• Maximum bit width: 65535

Parameters

Shift Mode — Type and direction of shift

Shift Left Logical (default) | Shift Right Logical | Shift Right Arithmetic

Specifies the type and direction of shift.

Programmatic Use

Block parameter: mode

Type: string scalar | character vector

Value: "Shift Left Logical" | "Shift Right Logical" | "Shift Right Arithmetic"

Default: 'Shift Left Logical'

Shift Length — Number of bits to be shifted

0 (default)

Specifies the number of bits to be shifted. Specify a value greater than or equal to zero.

Programmatic Use

Block parameter: N

Type: string scalar | character vector

Value: A value greater than or equal to zero

Default: '0'

Programmatic Use: Add Block

To add the block programmatically, use the add_block function with one of these library block paths as the source.

"hdlsllib/Logic and Bit Operations/Bit Shift"

Example: add_block("hdlsllib/Logic and Bit Operations/Bit Shift","myModel/myBlock",MakeNameUnique="on")

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

HDL Code Generation

Generate VHDL, Verilog and SystemVerilog code for FPGA and ASIC designs using HDL Coder™.

HDL Coder™ provides additional configuration options that affect HDL implementation and synthesized logic.

HDL Architecture

This block has one default HDL architecture.

HDL Block Properties

General
ConstrainedOutputPipeline	Number of registers to place at the outputs by moving existing delays in the design. Distributed pipelining does not redistribute these registers. The default value is 0. For more details, see ConstrainedOutputPipeline.
InputPipeline	Number of input pipeline stages to insert in the generated code. Distributed pipelining and constrained output pipelining can move these registers. The default value is 0. For more details, see InputPipeline.
OutputPipeline	Number of output pipeline stages to insert in the generated code. Distributed pipelining and constrained output pipelining can move these registers. The default value is 0. For more details, see OutputPipeline.
SynthesisAttributes	Specifies the synthesis attributes for the blocks and block output signals in the model. The generated HDL code contains these attributes. For more information, see SynthesisAttributes.

Version History

Introduced in R2014a

R2026a: Specify synthesis attributes for blocks and block output signals

Use the SynthesisAttributes HDL block property to specify the synthesis attributes for the block and its output signals. HDL Coder includes these attributes in the generated HDL code.

R2024b: Maximum bit width is 65535 bits

The maximum bit width of the output signal is 65535 bits. Prior to R2024b, the maximum bit width was 128 bits.