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Diffstat (limited to 'newlib/libm/machine/spu/headers/erfd2.h')
| -rw-r--r-- | newlib/libm/machine/spu/headers/erfd2.h | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/newlib/libm/machine/spu/headers/erfd2.h b/newlib/libm/machine/spu/headers/erfd2.h new file mode 100644 index 000000000..2ee71feaf --- /dev/null +++ b/newlib/libm/machine/spu/headers/erfd2.h @@ -0,0 +1,146 @@ +/* -------------------------------------------------------------- */ +/* (C)Copyright 2006,2007, */ +/* International Business Machines 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 _ERFD2_H_ +#define _ERFD2_H_ 1 + +#include <spu_intrinsics.h> + +#include "expd2.h" +#include "recipd2.h" +#include "divd2.h" +#include "erf_utils.h" + +/* + * FUNCTION + * vector double _erfd2(vector double x) + * + * DESCRIPTION + * The erfd2 function computes the error function of each element of x. + * + * C99 Special Cases: + * - erf(+0) returns +0 + * - erf(-0) returns -0 + * - erf(+infinite) returns +1 + * - erf(-infinite) returns -1 + * + * Other Cases: + * - erf(Nan) returns Nan + * + */ + +static __inline vector double _erfd2(vector double x) +{ + vec_uchar16 dup_even = ((vec_uchar16) { 0,1,2,3, 0,1,2,3, 8, 9,10,11, 8, 9,10,11 }); + vec_double2 onehalfd = spu_splats(0.5); + vec_double2 zerod = spu_splats(0.0); + vec_double2 oned = spu_splats(1.0); + vec_double2 sign_mask = spu_splats(-0.0); + + /* This is where we switch from Taylor Series to Continued Fraction approximation */ + vec_float4 approx_point = spu_splats(1.77f); + + vec_double2 xabs, xsqu, xsign; + vec_uint4 xabshigh; + vec_uint4 isinf, isnan; + vec_double2 tresult, presult, result; + + xsign = spu_and(x, sign_mask); + + /* Force Denorms to 0 */ + x = spu_add(x, zerod); + + xabs = spu_andc(x, sign_mask); + xsqu = spu_mul(x, x); + + /* + * Taylor Series Expansion near Zero + */ + TAYLOR_ERF(xabs, xsqu, tresult); + + /* + * Continued Fraction Approximation of Erfc(). + * erf = 1 - erfc + */ + CONTFRAC_ERFC(xabs, xsqu, presult); + presult = spu_sub(oned, presult); + + + /* + * Select the appropriate approximation. + */ + vec_float4 xf = spu_roundtf(xabs); + xf = spu_shuffle(xf, xf, dup_even); + result = spu_sel(tresult, presult, (vec_ullong2)spu_cmpgt(xf, approx_point)); + + + /* + * Special cases/errors. + */ + xabshigh = (vec_uint4)spu_shuffle(xabs, xabs, dup_even); + + /* x = +/- infinite, return +/-1 */ + isinf = spu_cmpeq(xabshigh, 0x7FF00000); + result = spu_sel(result, oned, (vec_ullong2)isinf); + + /* x = nan, return x */ + isnan = spu_cmpgt(xabshigh, 0x7FF00000); + result = spu_sel(result, x, (vec_ullong2)isnan); + + /* + * Preserve sign in result, since erf(-x) = -erf(x) + */ + result = spu_or(result, xsign); + + return result; +} + +#endif /* _ERFD2_H_ */ +#endif /* __SPU__ */ |