Sfpu recip sqrt implementation

[vkrsmanovicTT]

Ticket

N/A - Initial SFPU rsqrt implementation for Quasar architecture
Problem description

The Quasar architecture needed an implementation of the rsqrt (reciprocal square root: 1/sqrt(x)) SFPU operation.
What's changed
Core Implementation:
Added ckernel_sfpu_rsqrt.h for Quasar with SFPU instructions to compute rsqrt using hardware sqrt and reciprocal operations
Implemented rsqrt by chaining SQRT_MODE and RECIP_MODE SFPU nonlinear instructions
Test Infrastructure:
Added test_sfpu_rsqrt_quasar.py Python test with random input generation in range [0.01, 1.0]
Added sfpu_rsqrt_quasar_test.cpp C++ kernel implementing datacopy + SFPU pipeline
Current Status:
Implementation is working for a limited set of format combinations (Float16 input/output)
Test sweep currently covers basic approximation mode and destination accumulation variants
Test sweep will be expanded in future updates to cover additional data formats, tile sizes, and edge cases
Type of change
[ ] Bug fix (non-breaking change which fixes an issue)
[x] New feature (non-breaking change which adds functionality)
[ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
[ ] Documentation update

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[Copilot]

Pull request overview

This PR implements the rsqrt (reciprocal square root: 1/sqrt(x)) SFPU operation for the Quasar architecture. The implementation chains hardware SQRT and RECIP operations to compute rsqrt, adds comprehensive test infrastructure with Python and C++ tests, and includes supporting changes to helper utilities.

• Adds core rsqrt kernel implementation by chaining SQRT_MODE and RECIP_MODE SFPU instructions
• Implements test infrastructure with random input generation in range [0.01, 1.0] and golden reference validation
• Enhances PCC calculation to better handle edge cases with masked/invalid values

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tt_llk_quasar/llk_lib/llk_defs.h	Adds rsqrt enum value to SfpuType enumeration
tt_llk_quasar/common/inc/sfpu/ckernel_sfpu_rsqrt.h	Core rsqrt implementation chaining sqrt and reciprocal SFPU operations
tests/sources/quasar/sfpu_rsqrt_quasar_test.cpp	C++ kernel test implementing datacopy + SFPU rsqrt pipeline
tests/python_tests/quasar/test_sfpu_rsqrt_quasar.py	Python test with parametrized configurations and golden reference validation
tests/python_tests/helpers/utils.py	Refactors PCC calculation to handle edge cases more robustly
tests/python_tests/helpers/test_variant_parameters.py	Updates operation constant generation to handle Quasar SfpuType namespace
tests/python_tests/helpers/test_config.py	Adds null check for dest_acc before format inference
tests/python_tests/helpers/device.py	Skips assert handling for Quasar architecture

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