103 lines
3.4 KiB
C
103 lines
3.4 KiB
C
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/******************************************************************************
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Copyright (C) 2020 by Hugh Bailey <obs.jim@gmail.com>
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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******************************************************************************/
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/******************************************************************************
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The MIT License (MIT)
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Copyright (c) 2011-2019 Microsoft Corp
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Permission is hereby granted, free of charge, to any person obtaining a copy of this
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software and associated documentation files (the "Software"), to deal in the Software
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without restriction, including without limitation the rights to use, copy, modify,
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merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
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permit persons to whom the Software is furnished to do so, subject to the following
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conditions:
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The above copyright notice and this permission notice shall be included in all copies
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or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
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INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
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PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
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CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
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OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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******************************************************************************/
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#pragma once
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#include "math-defs.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct half {
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uint16_t u;
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};
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/* adapted from DirectXMath XMConvertFloatToHalf */
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static struct half half_from_float(float f)
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{
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uint32_t Result;
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uint32_t IValue;
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memcpy(&IValue, &f, sizeof(IValue));
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uint32_t Sign = (IValue & 0x80000000U) >> 16U;
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IValue = IValue & 0x7FFFFFFFU; // Hack off the sign
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if (IValue > 0x477FE000U) {
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// The number is too large to be represented as a half. Saturate to infinity.
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if (((IValue & 0x7F800000) == 0x7F800000) &&
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((IValue & 0x7FFFFF) != 0)) {
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Result = 0x7FFF; // NAN
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} else {
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Result = 0x7C00U; // INF
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}
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} else if (!IValue) {
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Result = 0;
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} else {
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if (IValue < 0x38800000U) {
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// The number is too small to be represented as a normalized half.
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// Convert it to a denormalized value.
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uint32_t Shift = 113U - (IValue >> 23U);
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IValue = (0x800000U | (IValue & 0x7FFFFFU)) >> Shift;
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} else {
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// Rebias the exponent to represent the value as a normalized half.
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IValue += 0xC8000000U;
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}
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Result = ((IValue + 0x0FFFU + ((IValue >> 13U) & 1U)) >> 13U) &
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0x7FFFU;
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}
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struct half h;
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h.u = (uint16_t)(Result | Sign);
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return h;
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}
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static struct half half_from_bits(uint16_t u)
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{
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struct half h;
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h.u = u;
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return h;
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}
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#ifdef __cplusplus
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}
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#endif
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