88 lines
2.7 KiB
C
88 lines
2.7 KiB
C
/*-
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* Copyright (c) 2011 David Schultz <das@FreeBSD.ORG>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "cdefs-compat.h"
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//__FBSDID("$FreeBSD: src/lib/msun/src/k_expf.c,v 1.1 2011/10/21 06:27:56 das Exp $");
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#include <openlibm_complex.h>
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#include <openlibm_math.h>
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#include "math_private.h"
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static const u_int32_t k = 235; /* constant for reduction */
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static const float kln2 = 162.88958740F; /* k * ln2 */
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/*
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* See k_exp.c for details.
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*
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* Input: ln(FLT_MAX) <= x < ln(2 * FLT_MAX / FLT_MIN_DENORM) ~= 192.7
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* Output: 2**127 <= y < 2**128
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*/
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static float
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__frexp_expf(float x, int *expt)
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{
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double exp_x;
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u_int32_t hx;
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exp_x = expf(x - kln2);
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GET_FLOAT_WORD(hx, exp_x);
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*expt = (hx >> 23) - (0x7f + 127) + k;
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SET_FLOAT_WORD(exp_x, (hx & 0x7fffff) | ((0x7f + 127) << 23));
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return (exp_x);
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}
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OLM_DLLEXPORT float
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__ldexp_expf(float x, int expt)
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{
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float exp_x, scale;
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int ex_expt;
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exp_x = __frexp_expf(x, &ex_expt);
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expt += ex_expt;
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SET_FLOAT_WORD(scale, (0x7f + expt) << 23);
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return (exp_x * scale);
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}
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OLM_DLLEXPORT float complex
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__ldexp_cexpf(float complex z, int expt)
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{
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float x, y, exp_x, scale1, scale2;
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int ex_expt, half_expt;
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x = crealf(z);
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y = cimagf(z);
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exp_x = __frexp_expf(x, &ex_expt);
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expt += ex_expt;
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half_expt = expt / 2;
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SET_FLOAT_WORD(scale1, (0x7f + half_expt) << 23);
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half_expt = expt - half_expt;
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SET_FLOAT_WORD(scale2, (0x7f + half_expt) << 23);
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return (CMPLXF(cosf(y) * exp_x * scale1 * scale2,
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sinf(y) * exp_x * scale1 * scale2));
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}
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