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Diffstat (limited to 'newlib/libm/machine/spu/headers/erfcf4.h')
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1 files changed, 133 insertions, 0 deletions
diff --git a/newlib/libm/machine/spu/headers/erfcf4.h b/newlib/libm/machine/spu/headers/erfcf4.h new file mode 100644 index 000000000..2f4774424 --- /dev/null +++ b/newlib/libm/machine/spu/headers/erfcf4.h @@ -0,0 +1,133 @@ +/* -------------------------------------------------------------- */ +/* (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 _ERFCF4_H_ +#define _ERFCF4_H_ 1 + +#include <spu_intrinsics.h> + +#include "expf4.h" +#include "recipf4.h" +#include "divf4.h" +#include "erf_utils.h" + +/* + * FUNCTION + * vector float _erfcf4(vector float x) + * + * DESCRIPTION + * The erfcf4 function computes the complement error function of each element of x. + * + * C99 Special Cases: + * - erfc(+0) returns +1 + * - erfc(-0) returns +1 + * - erfc(+infinite) returns +0 + * - erfc(-infinite) returns +2 + * + */ + +static __inline vector float _erfcf4(vector float x) +{ + vec_float4 onehalff = spu_splats(0.5f); + vec_float4 zerof = spu_splats(0.0f); + vec_float4 onef = spu_splats(1.0f); + vec_float4 twof = spu_splats(2.0f); + vec_float4 sign_mask = spu_splats(-0.0f); + + /* This is where we switch from near zero approx. */ + vec_float4 approx_point = spu_splats(0.89f); + + vec_float4 xabs, xsqu, xsign; + vec_uint4 isneg; + vec_float4 tresult, presult, result; + + xsign = spu_and(x, sign_mask); + + /* Force Denorms to 0 */ + x = spu_add(x, zerof); + + xabs = spu_andc(x, sign_mask); + xsqu = spu_mul(x, x); + + /* + * Use Taylor Series for x near 0 + * Preserve sign of x in result, since erf(-x) = -erf(x) + * This approximation is for erf, so adjust for erfc. + */ + TAYLOR_ERFF4(xabs, xsqu, tresult); + tresult = spu_or(tresult, xsign); + tresult = spu_sub(onef, tresult); + + /* + * Now, use the Continued Fractions approximation away + * from 0. If x < 0, use erfc(-x) = 2 - erfc(x) + */ + CONTFRAC_ERFCF4(xabs, xsqu, presult); + isneg = spu_rlmaska((vec_uint4)x, -32); + presult = spu_sel(presult, spu_sub(twof, presult), isneg); + + /* + * Select the appropriate approximation. + */ + result = spu_sel(tresult, presult, spu_cmpgt(xabs, approx_point)); + + /* + * Special cases/errors. + */ + + /* x = +/- infinite */ + result = spu_sel(result, zerof, spu_cmpeq((vec_uint4)xabs, 0x7F800000)); + result = spu_sel(result, twof, spu_cmpeq((vec_uint4)xabs, 0xFF800000)); + + return result; +} + +#endif /* _ERFCF4_H_ */ +#endif /* __SPU__ */ |