Bitwise Operator

Specified bitwise operation on inputs

• 

Libraries:
Simulink / Logic and Bit Operations
HDL Coder / Logic and Bit Operations

Description

The Bitwise Operator block performs the bitwise operation that you specify on one or more operands. Unlike logic operations of the Logical Operator block, bitwise operations treat the operands as a vector of bits rather than a single value.

Restrictions on Block Operations

The Bitwise Operator block does not support shift operations. For shift operations, use the Shift Arithmetic block.

When configured as a multi-input XOR gate, this block performs modulo-2 addition according to the IEEE^® Standard for Logic Elements.

Examples

Unsigned Inputs for the Bitwise Operator Block

The following model shows how the Bitwise Operator block works for unsigned inputs.

Each Constant block outputs an 8-bit unsigned integer (uint8). To determine the binary value of each Constant block output, use the dec2bin function. The results for all logic operations appear in the next table.

Signed Inputs for the Bitwise Operator Block

This example shows how the Bitwise Operator block works for signed inputs.

Each Constant block produces an 8-bit signed integer (int8). To determine the binary value of each Constant block output, use the dec2bin function. The table shows the results for all logic operations.

Ports

Input

Port_1 — Input signal

scalar | vector

Input signal, specified as a scalar or vector.

• The NOT operator accepts only one input, which can be a scalar or a vector. If the input is a vector, the output is a vector of the same size containing the bitwise logical complements of the input vector elements.

• For a single vector input, the block applies the operation (except the NOT operator) to all elements of the vector.

• For two or more inputs, the block performs the operation between all of the inputs. If the inputs are vectors, the block performs the operation between corresponding elements of the vectors to produce a vector output.

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

Output

Port_1 — Output signal

scalar | vector

The output signal specified as the output data type, which the block inherits from the driving block, must represent zero exactly. Data types that satisfy this condition include signed and unsigned integer data types.

The size of the block output depends on the number of inputs, the vector size, and the operator you select. If you do not specify a bit mask, the output is a scalar. If you do specify a bit mask, the output is a vector.

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

Parameters

Operator — Bitwise logical operator

AND (default) | OR | NOR | NAND | XOR | NOT

Specify the bitwise logical operator for the block operands.

You can select one of these bitwise operations:

Bitwise Operation	Description
AND	TRUE if the corresponding bits are all TRUE
OR	TRUE if at least one of the corresponding bits is TRUE
NAND	TRUE if at least one of the corresponding bits is FALSE
NOR	TRUE if no corresponding bits are TRUE
XOR	TRUE if an odd number of corresponding bits are TRUE
NOT	TRUE if the input is FALSE (available only for single input)

Programmatic Use

Block Parameter: logicop

Type: character vector

Values: 'AND'|'OR' |'NAND'|'NOR' |'XOR' | 'NOT'

Default: 'AND'

Use bit mask — Select to use bit mask

checked (default) | unchecked

Select to use the bit mask. Clearing this check box enables Number of input ports and disables Bit Mask and Treat mask as.

Programmatic Use

Block Parameter: UseBitMask

Type: character vector

Values: 'off'|'on'

Default: 'on'

Number of input ports — Number of input signals

1 (default) | integer

Specify the number of inputs. You can have more than one input ports.

Dependency

Clearing the Use bit mask check box enables Number of input ports and disables Bit Mask and Treat mask as.

Programmatic Use

Block Parameter: NumInputPorts

Type: character vector

Values: positive integer

Default: '1'

Bit Mask — Bit mask to associate with a single input

bin2dec (default)

Specify the bit mask to associate with a single input. This parameter reads values as hexadecimal values.

You can use the bit mask to set, get, or clear a bit on the input.

To perform a...	Set the Operator parameter to...	And create a bit mask with...
Bit set	OR	A 1 for each corresponding input bit that you want to set to 1
Bit clear	AND	A 0 for each corresponding input bit that you want to set to 0
Bit get	AND	A 1 for each corresponding input bit that you want to get

Suppose you want to set the fourth bit of an 8-bit input vector. The bit mask would be 00010000, which you can specify as 2^4 for the Bit Mask parameter. To clear the bit, the bit mask would be 11101111, which you can specify as 2^7+2^6+2^5+2^3+2^2+2^1+2^0 for the Bit Mask parameter.

Tip

Do not use a mask greater than 53 bits. Otherwise, an error message appears during simulation.

Dependency

This parameter is available only when you select Use bit mask.

Programmatic Use

Block Parameter: BitMask

Type: character vector

Values: positive integer

Default: 'bin2dec('11011001')'

Treat mask as — Treat the mask as a real-world value or a stored integer

Stored Integer (default) | Real World Value

Specify whether to treat the mask as a real-world value or a stored integer.

The encoding scheme is V = SQ + B, as described in Scaling (Fixed-Point Designer) in the Fixed-Point Designer™ documentation. Real World Value treats the mask as V. Stored Integer treats the mask as Q.

Dependency

This parameter is available only when you select Use bit mask.

Programmatic Use

Block Parameter: BitMaskRealWorld

Type: character vector

Values: 'Real World Value' | 'Stored Integer'

Default: 'Stored Integer'

Block Characteristics

Data Types	Booleana | fixed point | integer
Direct Feedthrough	no
Multidimensional Signals	yes
Variable-Size Signals	no
Zero-Crossing Detection	no
a Bit operations are not recommended for use with Boolean signals.

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

ConstrainedOutputPipeline	Number of registers to place at the outputs by moving existing delays within your design. Distributed pipelining does not redistribute these registers. The default is 0. For more details, see ConstrainedOutputPipeline (HDL Coder).
InputPipeline	Number of input pipeline stages to insert in the generated code. Distributed pipelining and constrained output pipelining can move these registers. The default is 0. For more details, see InputPipeline (HDL Coder).
OutputPipeline	Number of output pipeline stages to insert in the generated code. Distributed pipelining and constrained output pipelining can move these registers. The default is 0. For more details, see OutputPipeline (HDL Coder).

PLC Code Generation
Generate Structured Text code using Simulink® PLC Coder™.

Fixed-Point Conversion
Design and simulate fixed-point systems using Fixed-Point Designer™.

Version History

Introduced before R2006a