From 9d152e9c66c1094a482e704d95965078a0fe2cf3 Mon Sep 17 00:00:00 2001 From: Paul Elder Date: Wed, 27 Mar 2024 17:54:49 +0900 Subject: ipa: rkisp1: Add a helper to convert floating-point to fixed-point Add helper functions for converting between floating point and fixed point numbers. Also add tests for them. Signed-off-by: Paul Elder Reviewed-by: Stefan Klug Reviewed-by: Kieran Bingham --- src/ipa/rkisp1/meson.build | 1 + src/ipa/rkisp1/utils.cpp | 42 +++++++++++++++++++++++++++++ src/ipa/rkisp1/utils.h | 66 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 109 insertions(+) create mode 100644 src/ipa/rkisp1/utils.cpp create mode 100644 src/ipa/rkisp1/utils.h (limited to 'src/ipa/rkisp1') diff --git a/src/ipa/rkisp1/meson.build b/src/ipa/rkisp1/meson.build index e813da53..cf05cdb2 100644 --- a/src/ipa/rkisp1/meson.build +++ b/src/ipa/rkisp1/meson.build @@ -8,6 +8,7 @@ ipa_name = 'ipa_rkisp1' rkisp1_ipa_sources = files([ 'ipa_context.cpp', 'rkisp1.cpp', + 'utils.cpp', ]) rkisp1_ipa_sources += rkisp1_ipa_algorithms diff --git a/src/ipa/rkisp1/utils.cpp b/src/ipa/rkisp1/utils.cpp new file mode 100644 index 00000000..960ec64e --- /dev/null +++ b/src/ipa/rkisp1/utils.cpp @@ -0,0 +1,42 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2024, Paul Elder + * + * Miscellaneous utility functions specific to rkisp1 + */ + +#include "utils.h" + +/** + * \file utils.h + */ + +namespace libcamera { + +namespace ipa::rkisp1::utils { + +/** + * \fn R floatingToFixedPoint(T number) + * \brief Convert a floating point number to a fixed-point representation + * \tparam I Bit width of the integer part of the fixed-point + * \tparam F Bit width of the fractional part of the fixed-point + * \tparam R Return type of the fixed-point representation + * \tparam T Input type of the floating point representation + * \param number The floating point number to convert to fixed point + * \return The converted value + */ + +/** + * \fn R fixedToFloatingPoint(T number) + * \brief Convert a fixed-point number to a floating point representation + * \tparam I Bit width of the integer part of the fixed-point + * \tparam F Bit width of the fractional part of the fixed-point + * \tparam R Return type of the floating point representation + * \tparam T Input type of the fixed-point representation + * \param number The fixed point number to convert to floating point + * \return The converted value + */ + +} /* namespace ipa::rkisp1::utils */ + +} /* namespace libcamera */ diff --git a/src/ipa/rkisp1/utils.h b/src/ipa/rkisp1/utils.h new file mode 100644 index 00000000..450f2244 --- /dev/null +++ b/src/ipa/rkisp1/utils.h @@ -0,0 +1,66 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2024, Paul Elder + * + * Miscellaneous utility functions specific to rkisp1 + */ + +#pragma once + +#include +#include +#include + +namespace libcamera { + +namespace ipa::rkisp1::utils { + +#ifndef __DOXYGEN__ +template && + std::is_floating_point_v> * = nullptr> +#else +template +#endif +constexpr R floatingToFixedPoint(T number) +{ + static_assert(sizeof(int) >= sizeof(R)); + static_assert(I + F <= sizeof(R) * 8); + + /* + * The intermediate cast to int is needed on arm platforms to properly + * cast negative values. See + * https://embeddeduse.com/2013/08/25/casting-a-negative-float-to-an-unsigned-int/ + */ + R mask = (1 << (F + I)) - 1; + R frac = static_cast(static_cast(std::round(number * (1 << F)))) & mask; + + return frac; +} + +#ifndef __DOXYGEN__ +template && + std::is_integral_v> * = nullptr> +#else +template +#endif +constexpr R fixedToFloatingPoint(T number) +{ + static_assert(sizeof(int) >= sizeof(T)); + static_assert(I + F <= sizeof(T) * 8); + + /* + * Recreate the upper bits in case of a negative number by shifting the sign + * bit from the fixed point to the first bit of the unsigned and then right shifting + * by the same amount which keeps the sign bit in place. + * This can be optimized by the compiler quite well. + */ + int remaining_bits = sizeof(int) * 8 - (I + F); + int t = static_cast(static_cast(number) << remaining_bits) >> remaining_bits; + return static_cast(t) / static_cast(1 << F); +} + +} /* namespace ipa::rkisp1::utils */ + +} /* namespace libcamera */ -- cgit v1.2.1