115 lines
3.6 KiB
C++
115 lines
3.6 KiB
C++
// This code contains NVIDIA Confidential Information and is disclosed to you
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// under a form of NVIDIA software license agreement provided separately to you.
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//
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// Notice
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// NVIDIA Corporation and its licensors retain all intellectual property and
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// proprietary rights in and to this software and related documentation and
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// any modifications thereto. Any use, reproduction, disclosure, or
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// distribution of this software and related documentation without an express
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// license agreement from NVIDIA Corporation is strictly prohibited.
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//
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// ALL NVIDIA DESIGN SPECIFICATIONS, CODE ARE PROVIDED "AS IS.". NVIDIA MAKES
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// NO WARRANTIES, EXPRESSED, IMPLIED, STATUTORY, OR OTHERWISE WITH RESPECT TO
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// THE MATERIALS, AND EXPRESSLY DISCLAIMS ALL IMPLIED WARRANTIES OF NONINFRINGEMENT,
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// MERCHANTABILITY, AND FITNESS FOR A PARTICULAR PURPOSE.
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//
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// Information and code furnished is believed to be accurate and reliable.
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// However, NVIDIA Corporation assumes no responsibility for the consequences of use of such
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// information or for any infringement of patents or other rights of third parties that may
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// result from its use. No license is granted by implication or otherwise under any patent
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// or patent rights of NVIDIA Corporation. Details are subject to change without notice.
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// This code supersedes and replaces all information previously supplied.
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// NVIDIA Corporation products are not authorized for use as critical
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// components in life support devices or systems without express written approval of
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// NVIDIA Corporation.
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//
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// Copyright (c) 2008-2020 NVIDIA Corporation. All rights reserved.
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// Copyright (c) 2004-2008 AGEIA Technologies, Inc. All rights reserved.
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// Copyright (c) 2001-2004 NovodeX AG. All rights reserved.
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#ifndef PSFOUNDATION_PSBITUTILS_H
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#define PSFOUNDATION_PSBITUTILS_H
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#include "foundation/PxIntrinsics.h"
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#include "../Callbacks.h"
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#include "PsIntrinsics.h"
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#include "Ps.h"
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/** \brief NVidia namespace */
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namespace nv
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{
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/** \brief nvcloth namespace */
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namespace cloth
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{
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namespace ps
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{
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PX_INLINE uint32_t bitCount(uint32_t v)
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{
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// from http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel
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uint32_t const w = v - ((v >> 1) & 0x55555555);
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uint32_t const x = (w & 0x33333333) + ((w >> 2) & 0x33333333);
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return (((x + (x >> 4)) & 0xF0F0F0F) * 0x1010101) >> 24;
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}
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PX_INLINE bool isPowerOfTwo(uint32_t x)
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{
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return x != 0 && (x & (x - 1)) == 0;
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}
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// "Next Largest Power of 2
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// Given a binary integer value x, the next largest power of 2 can be computed by a SWAR algorithm
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// that recursively "folds" the upper bits into the lower bits. This process yields a bit vector with
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// the same most significant 1 as x, but all 1's below it. Adding 1 to that value yields the next
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// largest power of 2. For a 32-bit value:"
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PX_INLINE uint32_t nextPowerOfTwo(uint32_t x)
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{
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x |= (x >> 1);
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x |= (x >> 2);
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x |= (x >> 4);
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x |= (x >> 8);
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x |= (x >> 16);
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return x + 1;
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}
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/*!
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Return the index of the highest set bit. Not valid for zero arg.
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*/
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PX_INLINE uint32_t lowestSetBit(uint32_t x)
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{
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NV_CLOTH_ASSERT(x);
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return PxLowestSetBitUnsafe(x);
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}
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/*!
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Return the index of the highest set bit. Not valid for zero arg.
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*/
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PX_INLINE uint32_t highestSetBit(uint32_t x)
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{
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NV_CLOTH_ASSERT(x);
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return PxHighestSetBitUnsafe(x);
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}
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// Helper function to approximate log2 of an integer value
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// assumes that the input is actually power of two.
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// todo: replace 2 usages with 'highestSetBit'
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PX_INLINE uint32_t ilog2(uint32_t num)
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{
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for(uint32_t i = 0; i < 32; i++)
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{
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num >>= 1;
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if(num == 0)
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return i;
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}
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NV_CLOTH_ASSERT(0);
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return uint32_t(-1);
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}
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} // namespace ps
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} // namespace cloth
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} // namespace nv
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#endif // #ifndef PSFOUNDATION_PSBITUTILS_H
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