Sqrt

R2026b

Compute square root of fixed-point signal with QHL-compatible scaling

Since R2026b

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  • Sqrt block with an input and output.

Libraries:
Embedded Coder Support Package for Qualcomm Hexagon Processors / Hexagon / Math

Description

The Sqrt block computes the square root of a fixed-point input signal. The block supports fixed-point inputs and generates code that integrates with Qualcomm® Hexagon® library (QHL) for optimized execution.

Use this block when you want to simulate results to match QHL-generated code results for square root operations on Hexagon targets. The block implements a QHL-aligned algorithm so that model behaviour and generated code produce consistent results.

For fixed-point inputs, the block expects input values in unsigned Q0 format (16-bit) and produces output values in unsigned Q8.8 format. This scaling reflects the behaviour of the underlying QHL APIs. The block supports scalar and vector inputs and applies the element-wise square root operation.

The block computes the square root using a QHL implementation that first estimates the inverse square root and then refines the result using one Newton–Raphson iteration. The algorithm scales the result to produce an output in Q8.8 fixed-point format and ensures consistency between simulation and generated code.

You can use this block for fixed-point modeling, code generation, and execution on Qualcomm Hexagon DSP targets.

Examples

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This example uses:

Open Live Script

The model uses a fixed-point constant as input and passes the signal through the Sqrt block. The block computes the square root using QHL-compatible behavior and produces an output in Q8.8 fixed-point format. In this example you:

  • Create a fixed-point input signal in unsigned Q0 format.

  • Compute the square root using the Sqrt block.

  • Observe the output in Q8.8 fixed-point format.

  • Verify that the result matches the expected square root value.

To create the input, add a constant block to the model and set the Constant value to 16. Set the Output datatype to unit16.

Add the Sqrt block from the Qualcomm® Hexagon® Math library. Connect the Constant block to the input of the Sqrt block. Connect a Display block to the output of the Sqrt block.

To generate code for Qualcomm Hexagon targets, configure the model to use the Qualcomm Hexagon QHL code replacement library.

  • Press Ctrl+E to open the model settings.

  • Go to Hardware Implementation and set Hardware board to Qualcomm Hexagon Simulator or the appropriate Hexagon target.

  • Go to Code Generation → Interface and set Code Replacement Library to Qualcomm Hexagon QHL.

  • Run the simulation.

open_system('ComputeFixedPointSqrt')

Simulink model with a Constant block configured for unsigned 16‑bit fixed‑point output in Q0 format connected to a Sqrt block, which feeds a Display block that shows the square root result in unsigned Q8.8 fixed‑point format.

Ports

Input

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Input signal, specified as a scalar or vector. The block interprets the input as a 16-bit unsigned fixed-point value in Q0 format (integer-only representation).

Data Types: uint16

Output

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Output signal that represents the square root of the input signal. The block returns output values in unsigned Q8.8 fixed-point format, where the fractional bits provide precision for the square root result.

Data Types: uint16

Extended Capabilities

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

Version History

Introduced in R2026b