229 lines
7.1 KiB
C++
229 lines
7.1 KiB
C++
/****************************************************************************
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**
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** Copyright (C) 2016 by Southwest Research Institute (R)
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** Contact: http://www.qt-project.org/legal
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**
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** This file is part of the QtCore module of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:LGPL$
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** Commercial License Usage
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** Licensees holding valid commercial Qt licenses may use this file in
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** accordance with the commercial license agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and The Qt Company. For licensing terms
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** and conditions see https://www.qt.io/terms-conditions. For further
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** information use the contact form at https://www.qt.io/contact-us.
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**
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** GNU Lesser General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** General Public License version 3 as published by the Free Software
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** Foundation and appearing in the file LICENSE.LGPL3 included in the
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** packaging of this file. Please review the following information to
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** ensure the GNU Lesser General Public License version 3 requirements
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** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
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**
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** GNU General Public License Usage
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** Alternatively, this file may be used under the terms of the GNU
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** General Public License version 2.0 or (at your option) the GNU General
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** Public license version 3 or any later version approved by the KDE Free
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** Qt Foundation. The licenses are as published by the Free Software
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** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
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** included in the packaging of this file. Please review the following
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** information to ensure the GNU General Public License requirements will
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** be met: https://www.gnu.org/licenses/gpl-2.0.html and
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** https://www.gnu.org/licenses/gpl-3.0.html.
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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#include "qfloat16_p.h"
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#include "private/qsimd_p.h"
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QT_BEGIN_NAMESPACE
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/*!
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\headerfile <QFloat16>
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\title 16-bit Floating Point Support
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\ingroup funclists
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\brief The <QFloat16> header file provides 16-bit floating point support.
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This header file provides support for half-precision (16-bit) floating
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point data with the class \c qfloat16. It is fully compliant with IEEE
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754 as a storage type. This implies that any arithmetic operation on a
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\c qfloat16 instance results in the value first being converted to a
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\c float. This conversion to and from \c float is performed by hardware
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when possible, but on processors that do not natively support half-precision,
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the conversion is performed through a sequence of lookup table operations.
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\c qfloat16 should be treated as if it were a POD (plain old data) type.
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Consequently, none of the supported operations need any elaboration beyond
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stating that it supports all arithmetic operators incident to floating point
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types.
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\since 5.9
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*/
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/*!
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\macro QT_NO_FLOAT16_OPERATORS
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\relates <QFloat16>
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\since 5.12.4
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Defining this macro disables the arithmetic operators for qfloat16.
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This is only necessary on Visual Studio 2017 (and earlier) when including
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\c {<QFloat16>} and \c{<bitset>} in the same translation unit, which would
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otherwise cause a compilation error due to a toolchain bug (see
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[QTBUG-72073]).
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*/
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/*!
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Returns true if the \c qfloat16 \a {f} is equivalent to infinity.
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\relates <QFloat16>
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\sa qIsInf
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*/
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Q_REQUIRED_RESULT bool qIsInf(qfloat16 f) Q_DECL_NOTHROW { return qt_is_inf(f); }
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/*!
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Returns true if the \c qfloat16 \a {f} is not a number (NaN).
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\relates <QFloat16>
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\sa qIsNaN
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*/
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Q_REQUIRED_RESULT bool qIsNaN(qfloat16 f) Q_DECL_NOTHROW { return qt_is_nan(f); }
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/*!
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Returns true if the \c qfloat16 \a {f} is a finite number.
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\relates <QFloat16>
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\sa qIsFinite
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*/
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Q_REQUIRED_RESULT bool qIsFinite(qfloat16 f) Q_DECL_NOTHROW { return qt_is_finite(f); }
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/*! \fn int qRound(qfloat16 value)
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\relates <QFloat16>
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Rounds \a value to the nearest integer.
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\sa qRound
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*/
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/*! \fn qint64 qRound64(qfloat16 value)
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\relates <QFloat16>
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Rounds \a value to the nearest 64-bit integer.
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\sa qRound64
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*/
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/*! \fn bool qFuzzyCompare(qfloat16 p1, qfloat16 p2)
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\relates <QFloat16>
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Compares the floating point value \a p1 and \a p2 and
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returns \c true if they are considered equal, otherwise \c false.
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The two numbers are compared in a relative way, where the
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exactness is stronger the smaller the numbers are.
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*/
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#if QT_COMPILER_SUPPORTS(F16C)
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static inline bool hasFastF16()
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{
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// All processors with F16C also support AVX, but YMM registers
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// might not be supported by the OS, or they might be disabled.
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return qCpuHasFeature(F16C) && qCpuHasFeature(AVX);
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}
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extern "C" {
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#ifdef QFLOAT16_INCLUDE_FAST
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# define f16cextern static
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#else
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# define f16cextern extern
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#endif
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f16cextern void qFloatToFloat16_fast(quint16 *out, const float *in, qsizetype len) Q_DECL_NOTHROW;
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f16cextern void qFloatFromFloat16_fast(float *out, const quint16 *in, qsizetype len) Q_DECL_NOTHROW;
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#undef f16cextern
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}
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#elif defined(__ARM_FP16_FORMAT_IEEE) && defined(__ARM_NEON__)
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static inline bool hasFastF16()
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{
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return true;
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}
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static void qFloatToFloat16_fast(quint16 *out, const float *in, qsizetype len) Q_DECL_NOTHROW
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{
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__fp16 *out_f16 = reinterpret_cast<__fp16 *>(out);
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qsizetype i = 0;
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for (; i < len - 3; i += 4)
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vst1_f16(out_f16 + i, vcvt_f16_f32(vld1q_f32(in + i)));
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SIMD_EPILOGUE(i, len, 3)
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out_f16[i] = __fp16(in[i]);
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}
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static void qFloatFromFloat16_fast(float *out, const quint16 *in, qsizetype len) Q_DECL_NOTHROW
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{
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const __fp16 *in_f16 = reinterpret_cast<const __fp16 *>(in);
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qsizetype i = 0;
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for (; i < len - 3; i += 4)
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vst1q_f32(out + i, vcvt_f32_f16(vld1_f16(in_f16 + i)));
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SIMD_EPILOGUE(i, len, 3)
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out[i] = float(in_f16[i]);
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}
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#else
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static inline bool hasFastF16()
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{
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return false;
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}
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static void qFloatToFloat16_fast(quint16 *, const float *, qsizetype) Q_DECL_NOTHROW
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{
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Q_UNREACHABLE();
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}
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static void qFloatFromFloat16_fast(float *, const quint16 *, qsizetype) Q_DECL_NOTHROW
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{
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Q_UNREACHABLE();
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}
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#endif
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/*!
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\since 5.11
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\relates <QFloat16>
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Converts \a len floats from \a in to qfloat16 and stores them in \a out.
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Both \a in and \a out must have \a len allocated entries.
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*/
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Q_CORE_EXPORT void qFloatToFloat16(qfloat16 *out, const float *in, qsizetype len) Q_DECL_NOTHROW
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{
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if (hasFastF16())
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return qFloatToFloat16_fast(reinterpret_cast<quint16 *>(out), in, len);
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for (qsizetype i = 0; i < len; ++i)
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out[i] = qfloat16(in[i]);
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}
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/*!
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\since 5.11
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\relates <QFloat16>
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Converts \a len qfloat16 from \a in to floats and stores them in \a out.
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Both \a in and \a out must have \a len allocated entries.
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*/
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Q_CORE_EXPORT void qFloatFromFloat16(float *out, const qfloat16 *in, qsizetype len) Q_DECL_NOTHROW
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{
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if (hasFastF16())
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return qFloatFromFloat16_fast(out, reinterpret_cast<const quint16 *>(in), len);
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for (qsizetype i = 0; i < len; ++i)
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out[i] = float(in[i]);
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}
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QT_END_NAMESPACE
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#ifdef QFLOAT16_INCLUDE_FAST
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# include "qfloat16_f16c.c"
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#endif
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