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// Copyright (c) 2008-2019 NVIDIA Corporation. All rights reserved.
// Copyright (c) 2004-2008 AGEIA Technologies, Inc. All rights reserved.
// Copyright (c) 2001-2004 NovodeX AG. All rights reserved.

#ifndef PSFOUNDATION_PSUNIXINTRINSICS_H
#define PSFOUNDATION_PSUNIXINTRINSICS_H

#include "Ps.h"
#include "foundation/PxAssert.h"
#include <math.h>

#if PX_ANDROID
#include <signal.h> // for Ns::debugBreak() { raise(SIGTRAP); }
#endif

#if 0
#include <libkern/OSAtomic.h>
#endif

// this file is for internal intrinsics - that is, intrinsics that are used in
// cross platform code but do not appear in the API

#if !(PX_LINUX || PX_ANDROID || PX_PS4 || PX_APPLE_FAMILY)
#error "This file should only be included by unix builds!!"
#endif

namespace physx
{
namespace shdfnd
{

PX_FORCE_INLINE void memoryBarrier()
{
	__sync_synchronize();
}

/*!
Return the index of the highest set bit. Undefined for zero arg.
*/
PX_INLINE uint32_t highestSetBitUnsafe(uint32_t v)
{

	return 31 - __builtin_clz(v);
}

/*!
Return the index of the highest set bit. Undefined for zero arg.
*/
PX_INLINE int32_t lowestSetBitUnsafe(uint32_t v)
{
	return __builtin_ctz(v);
}

/*!
Returns the index of the highest set bit. Returns 32 for v=0.
*/
PX_INLINE uint32_t countLeadingZeros(uint32_t v)
{
	if(v)
		return __builtin_clz(v);
	else
		return 32;
}

/*!
Prefetch aligned 64B x86, 32b ARM around \c ptr+offset.
*/
PX_FORCE_INLINE void prefetchLine(const void* ptr, uint32_t offset = 0)
{
	__builtin_prefetch(reinterpret_cast<const char* PX_RESTRICT>(ptr) + offset, 0, 3);
}

/*!
Prefetch \c count bytes starting at \c ptr.
*/
#if PX_ANDROID || PX_IOS
PX_FORCE_INLINE void prefetch(const void* ptr, uint32_t count = 1)
{
	const char* cp = static_cast<const char*>(ptr);
	size_t p = reinterpret_cast<size_t>(ptr);
	uint32_t startLine = uint32_t(p >> 5), endLine = uint32_t((p + count - 1) >> 5);
	uint32_t lines = endLine - startLine + 1;
	do
	{
		prefetchLine(cp);
		cp += 32;
	} while(--lines);
}
#else
PX_FORCE_INLINE void prefetch(const void* ptr, uint32_t count = 1)
{
	const char* cp = reinterpret_cast<const char*>(ptr);
	uint64_t p = size_t(ptr);
	uint64_t startLine = p >> 6, endLine = (p + count - 1) >> 6;
	uint64_t lines = endLine - startLine + 1;
	do
	{
		prefetchLine(cp);
		cp += 64;
	} while(--lines);
}
#endif

//! \brief platform-specific reciprocal
PX_CUDA_CALLABLE PX_FORCE_INLINE float recipFast(float a)
{
	return 1.0f / a;
}

//! \brief platform-specific fast reciprocal square root
PX_CUDA_CALLABLE PX_FORCE_INLINE float recipSqrtFast(float a)
{
	return 1.0f / ::sqrtf(a);
}

//! \brief platform-specific floor
PX_CUDA_CALLABLE PX_FORCE_INLINE float floatFloor(float x)
{
	return ::floorf(x);
}

#define NS_EXPECT_TRUE(x) x
#define NS_EXPECT_FALSE(x) x

} // namespace shdfnd
} // namespace physx

#endif // #ifndef PSFOUNDATION_PSUNIXINTRINSICS_H