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