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Diffstat (limited to 'newlib/libm/machine/spu/headers/log2f.h')
| -rw-r--r-- | newlib/libm/machine/spu/headers/log2f.h | 124 |
1 files changed, 0 insertions, 124 deletions
diff --git a/newlib/libm/machine/spu/headers/log2f.h b/newlib/libm/machine/spu/headers/log2f.h deleted file mode 100644 index 26717c7c0..000000000 --- a/newlib/libm/machine/spu/headers/log2f.h +++ /dev/null @@ -1,124 +0,0 @@ -/* - (C) Copyright 2001,2006, - International Business Machines Corporation, - Sony Computer Entertainment, Incorporated, - Toshiba Corporation, - - All rights reserved. - - Redistribution and use in source and binary forms, with or without - modification, are permitted provided that the following conditions are met: - - * Redistributions of source code must retain the above copyright notice, - this list of conditions and the following disclaimer. - * Redistributions in binary form must reproduce the above copyright - notice, this list of conditions and the following disclaimer in the - documentation and/or other materials provided with the distribution. - * Neither the names of the copyright holders nor the names of their - contributors may be used to endorse or promote products derived from this - software without specific prior written permission. - - THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS - IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED - TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A - PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER - OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, - EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, - PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR - PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF - LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING - NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS - SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -*/ -#ifndef _LOG2F_H_ -#define _LOG2F_H_ 1 - -#include <spu_intrinsics.h> -#include "headers/dom_chkf_less_than.h" - -/* - * FUNCTION - * float _log2f(float x) - * - * DESCRIPTION - * _log2f computes log (base 2) of the input value x. The log2f - * function is approximated as a polynomial of order 8 - * (C. Hastings, Jr, 1955). - * - * __8__ - * \ - * \ - * log2f(1+x) = / Ci*x^i - * /____ - * i=1 - * - * for x in the range 0.0 to 1.0 - * - * C1 = 1.4426898816672 - * C2 = -0.72116591947498 - * C3 = 0.47868480909345 - * C4 = -0.34730547155299 - * C5 = 0.24187369696082 - * C6 = -0.13753123777116 - * C7 = 0.052064690894143 - * C8 = -0.0093104962134977 - * - * This function assumes that x is a non-zero positive value. - */ - -static __inline float _log2f(float x) -{ - union { - unsigned int ui; - float f; - } in; - int exponent; - float result; - float x2, x4; - float hi, lo; - vector float vx; - vector float vc = { 0.0, 0.0, 0.0, 0.0 }; - - in.f = x; - - /* Extract the exponent from the input X. - */ - exponent = (signed)((in.ui >> 23) & 0xFF) - 127; - - /* Compute the remainder after removing the exponent. - */ - in.ui -= exponent << 23; - - /* Calculate the log2 of the remainder using the polynomial - * approximation. - */ - x = in.f - 1.0f; - - /* Instruction counts can be reduced if the polynomial was - * computed entirely from nested (dependent) fma's. However, - * to reduce the number of pipeline stalls, the polygon is evaluated - * in two halves (hi amd lo). - */ - x2 = x * x; - x4 = x2 * x2; - hi = -0.0093104962134977f*x + 0.052064690894143f; - hi = hi*x - 0.13753123777116f; - hi = hi*x + 0.24187369696082f; - hi = hi*x - 0.34730547155299f; - lo = 0.47868480909345f *x - 0.72116591947498f; - lo = lo*x + 1.4426898816672f; - lo = lo*x; - result = hi*x4 + lo; - - /* Add the exponent back into the result. - */ - result += (float)(exponent); - -#ifndef _IEEE_LIBM - vx = spu_promote(x, 0); - dom_chkf_less_than(vx, vc); -#endif - return (result); -} - -#endif /* _LOG2F_H_ */ |