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23 lines
543 B
C
23 lines
543 B
C
#ifndef _MATH_PPC_H_
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#define _MATH_PPC_H_
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inline float sqrtf(float x)
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{
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static const double _half=.5;
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static const double _three=3.0;
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volatile float y;
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if(x > 0.0f)
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{
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double guess = __frsqrte((double)x); /* returns an approximation to */
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guess = _half*guess*(_three - guess*guess*x); /* now have 12 sig bits */
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guess = _half*guess*(_three - guess*guess*x); /* now have 24 sig bits */
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guess = _half*guess*(_three - guess*guess*x); /* now have 32 sig bits */
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y=(float)(x*guess);
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return y ;
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}
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return x ;
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}
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#endif
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