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Diffstat (limited to 'newlib/libm/machine/spu/headers/expf4.h')
| -rw-r--r-- | newlib/libm/machine/spu/headers/expf4.h | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/newlib/libm/machine/spu/headers/expf4.h b/newlib/libm/machine/spu/headers/expf4.h new file mode 100644 index 000000000..e8c68c163 --- /dev/null +++ b/newlib/libm/machine/spu/headers/expf4.h @@ -0,0 +1,124 @@ +/* -------------------------------------------------------------- */ +/* (C)Copyright 2006,2007, */ +/* 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 name of IBM Corporation nor the names of its */ +/* contributors may be used to endorse or promote products */ +/* derived from this software without specific prior written */ +/* permission. */ +/* 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 name of IBM Corporation nor the names of its */ +/* 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. */ +/* -------------------------------------------------------------- */ +/* PROLOG END TAG zYx */ +#ifdef __SPU__ +#ifndef _EXPF4_H_ +#define _EXPF4_H_ 1 + + +#include "floorf4.h" +#include "ldexpf4.h" + +/* + * FUNCTION + * vector float _expf4(vector float x) + * + * DESCRIPTION + * The _expf4 function computes e raised to the input x for + * each of the element of the float vector. + * + */ +static __inline vector float _expf4(vector float x) +{ + + // log2(e) + vec_float4 log2e = spu_splats(1.4426950408889634074f); + + // Extra precision for the ln2 multiply + vec_float4 ln2_hi = spu_splats(0.693359375f); + vec_float4 ln2_lo = spu_splats(-2.12194440E-4f); + + // Coefficents for the Taylor series + vec_float4 f02 = spu_splats(5.0000000000000000E-1f); // 1/2! + vec_float4 f03 = spu_splats(1.6666666666666667E-1f); // 1/3! + vec_float4 f04 = spu_splats(4.1666666666666667E-2f); // 1/4! + vec_float4 f05 = spu_splats(8.3333333333333333E-3f); // 1/5! + vec_float4 f06 = spu_splats(1.3888888888888889E-3f); // 1/6! + vec_float4 f07 = spu_splats(1.9841269841269841E-4f); // 1/7! + + // Range reduce input, so that: + // e^x = e^z * 2^n + // e^x = e^z * e^(n * ln(2)) + // e^x = e^(z + (n * ln(2))) + + vec_int4 n; // exponent of reduction + vec_float4 q; // range reduced result + + vec_float4 z; + vec_float4 r; + + z = spu_madd(x,log2e,spu_splats(0.5f)); + z = _floorf4(z); + r = spu_nmsub(z,ln2_hi,x); + r = spu_nmsub(z,ln2_lo,r); + n = spu_convts(z,0); + z = spu_mul(r,r); + + // Use Horner's method on the Taylor series + q = spu_madd(r,f07,f06); + q = spu_madd(q,r,f05); + q = spu_madd(q,r,f04); + q = spu_madd(q,r,f03); + q = spu_madd(q,r,f02); + q = spu_madd(q,z,r); + q = spu_add(q,spu_splats(1.0f)); + + // Adjust the result by the range reduction + r = _ldexpf4( q, n ); + + return(r); + +} + +#endif /* _EXPF4_H_ */ +#endif /* __SPU__ */ + |