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Diffstat (limited to 'newlib/libm/machine/spu/headers/exp2f.h')
| -rw-r--r-- | newlib/libm/machine/spu/headers/exp2f.h | 124 |
1 files changed, 0 insertions, 124 deletions
diff --git a/newlib/libm/machine/spu/headers/exp2f.h b/newlib/libm/machine/spu/headers/exp2f.h deleted file mode 100644 index 84bccdc04..000000000 --- a/newlib/libm/machine/spu/headers/exp2f.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 _EXP2F_H_ -#define _EXP2F_H_ 1 - -#ifndef M_LN2 -#define M_LN2 0.69314718055994530942 /* ln(2) */ -#endif /* M_LN2 */ - -/* - * FUNCTION - * float _exp2f(float x) - * - * DESCRIPTION - * _exp2f computes 2 raised to the input x. Computation is - * performed by observing the 2^(a+b) = 2^a * 2^b. - * We decompose x into a and b (above) by letting. - * a = ceil(x), b = x - a; - * - * 2^a is easilty computed by placing a into the exponent - * or a floating point number whose mantissa is all zeros. - * - * 2^b is computed using the following polynomial approximation. - * (C. Hastings, Jr, 1955). - * - * __7__ - * \ - * \ - * 2^x = / Ci*x^i - * /____ - * i=0 - * - * for x in the range 0.0 to 1.0 - * - * C0 = 1.0 - * C1 = -0.9999999995 - * C2 = 0.4999999206 - * C3 = -0.1666653019 - * C4 = 0.0416573475 - * C5 = -0.0083013598 - * C6 = 0.0013298820 - * C7 = -0.0001413161 - * - */ -static __inline float _exp2f(float x) -{ - union { - float f; - unsigned int ui; - } bias, exp_int, exp_frac; - unsigned int overflow, underflow; - int ix; - float frac, frac2, frac4; - float hi, lo; - - /* Break in the input x into two parts ceil(x), x - ceil(x). - */ - bias.f = x; - bias.ui = ~(unsigned int)((signed)(bias.ui) >> 31) & 0x3F7FFFFF; - ix = (int)(x + bias.f); - frac = (float)ix - x; - frac *= (float)(M_LN2); - - exp_int.ui = (ix + 127) << 23; - - overflow = (ix > 128) ? 0x7FFFFFFF : 0x0; - underflow = (ix < -127) ? 0xFFFFFFFF : 0x0; - - /* 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). - */ - frac2 = frac * frac; - frac4 = frac2 * frac2; - hi = -0.0001413161f * frac + 0.0013298820f; - hi = hi * frac - 0.0083013598f; - hi = hi * frac + 0.0416573475f; - lo = -0.1666653019f * frac + 0.4999999206f; - lo = lo * frac - 0.9999999995f; - lo = lo * frac + 1.0f; - exp_frac.f = hi * frac4 + lo; - - ix += exp_frac.ui >> 23; - exp_frac.f *= exp_int.f; - - exp_frac.ui = (exp_frac.ui | overflow) & ~underflow; - - return (exp_frac.f); -} - -#endif /* _EXP2F_H_ */ - - |