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//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
//=====================================================================================//
#ifndef _MATH_PFNS_H_
#define _MATH_PFNS_H_
#if defined( _X360 )
#include <xboxmath.h>
#endif
#if !defined( _X360 )
// These globals are initialized by mathlib and redirected based on available fpu features
extern float (*pfSqrt)(float x);
extern float (*pfRSqrt)(float x);
extern float (*pfRSqrtFast)(float x);
extern void (*pfFastSinCos)(float x, float *s, float *c);
extern float (*pfFastCos)(float x);
// The following are not declared as macros because they are often used in limiting situations,
// and sometimes the compiler simply refuses to inline them for some reason
#define FastSqrt(x) (*pfSqrt)(x)
#define FastRSqrt(x) (*pfRSqrt)(x)
#define FastRSqrtFast(x) (*pfRSqrtFast)(x)
#define FastSinCos(x,s,c) (*pfFastSinCos)(x,s,c)
#define FastCos(x) (*pfFastCos)(x)
#if defined(__i386__) || defined(_M_IX86)
// On x86, the inline FPU or SSE sqrt instruction is faster than
// the overhead of setting up a function call and saving/restoring
// the FPU or SSE register state and can be scheduled better, too.
#undef FastSqrt
#define FastSqrt(x) ::sqrtf(x)
#endif
#endif // !_X360
#if defined( _X360 )
FORCEINLINE float _VMX_Sqrt( float x )
{
return __fsqrts( x );
}
FORCEINLINE float _VMX_RSqrt( float x )
{
float rroot = __frsqrte( x );
// Single iteration NewtonRaphson on reciprocal square root estimate
return (0.5f * rroot) * (3.0f - (x * rroot) * rroot);
}
FORCEINLINE float _VMX_RSqrtFast( float x )
{
return __frsqrte( x );
}
FORCEINLINE void _VMX_SinCos( float a, float *pS, float *pC )
{
XMScalarSinCos( pS, pC, a );
}
FORCEINLINE float _VMX_Cos( float a )
{
return XMScalarCos( a );
}
// the 360 has fixed hw and calls directly
#define FastSqrt(x) _VMX_Sqrt(x)
#define FastRSqrt(x) _VMX_RSqrt(x)
#define FastRSqrtFast(x) _VMX_RSqrtFast(x)
#define FastSinCos(x,s,c) _VMX_SinCos(x,s,c)
#define FastCos(x) _VMX_Cos(x)
#endif // _X360
#endif // _MATH_PFNS_H_
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