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Imported tier1 and mathlib code from L4D2 SDK.

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Scott Ehlert
2012-05-21 02:48:36 -05:00
parent 5bd82f0928
commit b3de4b7059
62 changed files with 30858 additions and 0 deletions
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39
mathlib/powsse.cpp Normal file
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//========= Copyright <20> 1996-2005, Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
//=====================================================================================//
#include "mathlib/ssemath.h"
fltx4 Pow_FixedPoint_Exponent_SIMD( const fltx4 & x, int exponent)
{
fltx4 rslt=Four_Ones; // x^0=1.0
int xp=abs(exponent);
if (xp & 3) // fraction present?
{
fltx4 sq_rt=SqrtEstSIMD(x);
if (xp & 1) // .25?
rslt=SqrtEstSIMD(sq_rt); // x^.25
if (xp & 2)
rslt=MulSIMD(rslt,sq_rt);
}
xp>>=2; // strip fraction
fltx4 curpower=x; // curpower iterates through x,x^2,x^4,x^8,x^16...
while(1)
{
if (xp & 1)
rslt=MulSIMD(rslt,curpower);
xp>>=1;
if (xp)
curpower=MulSIMD(curpower,curpower);
else
break;
}
if (exponent<0)
return ReciprocalEstSIMD(rslt); // pow(x,-b)=1/pow(x,b)
else
return rslt;
}