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Diffstat (limited to 'newlib/libm/machine/spu/headers/sqrtf4.h')
-rw-r--r-- | newlib/libm/machine/spu/headers/sqrtf4.h | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/newlib/libm/machine/spu/headers/sqrtf4.h b/newlib/libm/machine/spu/headers/sqrtf4.h new file mode 100644 index 000000000..ef5ff3b69 --- /dev/null +++ b/newlib/libm/machine/spu/headers/sqrtf4.h @@ -0,0 +1,128 @@ +/* -------------------------------------------------------------- */ +/* (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 _SQRTF4_H_ +#define _SQRTF4_H_ 1 + +#include <spu_intrinsics.h> + +/* + * FUNCTION + * vector float _sqrtf4(vector float in) + * + * DESCRIPTION + * The _sqrtf4 function computes the square root of the vector input "in" + *and returns the result. + * + */ +static __inline vector float _sqrtf4(vector float in) +{ + vec_uint4 exp, valid; + vec_uint4 mask = spu_splats((unsigned int)0xFF000000); + vec_uint4 half = spu_splats((unsigned int)0x00800000); + vec_float4 one = spu_splats(1.0f); + vec_float4 three = spu_splats(3.0f); + vec_float4 x, y0, y1, y1_n1, y1_p1, y1_p2, y1_p3; + vec_float4 mant, err, err_p1, err_p2, err_p3; + vec_float4 out; + + /* Compute the mantissa of the result seperately from + * the exponent to assure complete accuracy over the allowable + * input range. The mantissa is computed for inputs in the + * range [0.5, 2.0). + */ + x = spu_sel(in, one, mask); + y0 = spu_rsqrte(x); + + /* Perform one iteration of the Newton-Raphsom method in single precision + * arithmetic. + */ + y1 = spu_mul(spu_nmsub(x, spu_mul(y0, y0), three), + spu_mul(y0, (vec_float4)(spu_sub((vec_uint4)(x), half)))); + + /* Correct the result for possible error. The range of error is -3 to +1. + * Identify the extent of the error and correct for it. + */ + y1_p3 = (vec_float4)spu_add((vec_uint4)(y1), 3); + y1_p2 = (vec_float4)spu_add((vec_uint4)(y1), 2); + y1_p1 = (vec_float4)spu_add((vec_uint4)(y1), 1); + y1_n1 = (vec_float4)spu_add((vec_uint4)(y1), -1); + + err = spu_nmsub(y1, y1, x); + err_p1 = spu_nmsub(y1_p1, y1_p1, x); + err_p2 = spu_nmsub(y1_p2, y1_p2, x); + err_p3 = spu_nmsub(y1_p3, y1_p3, x); + + mant = spu_sel(y1_n1, y1, spu_cmpgt((vec_int4)(err), -1)); + mant = spu_sel(mant, y1_p1, spu_cmpgt((vec_int4)(err_p1), -1)); + mant = spu_sel(mant, y1_p2, spu_cmpgt((vec_int4)(err_p2), -1)); + mant = spu_sel(mant, y1_p3, spu_cmpgt((vec_int4)(err_p3), -1)); + + /* Compute the expected exponent. If the exponent is zero or the input is + * negative, then set the result to zero. + */ + exp = spu_rlmask(spu_add((vec_uint4)(in), (vec_uint4)(one)), -1); + + valid = spu_cmpgt(spu_and((vec_int4)(in), (vec_int4)(mask)), 0); + + /* Merge the computed exponent and mantissa. + */ + out = spu_and(spu_sel(mant, (vec_float4)(exp), spu_splats(0xFF800000)), (vec_float4)(valid)); + + + return (out); + +} + +#endif /* _SQRTF4_H_ */ +#endif /* __SPU__ */ |