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       1                 :             : /*-
       2                 :             :  * Copyright (c) 2011 David Schultz <das@FreeBSD.ORG>
       3                 :             :  * All rights reserved.
       4                 :             :  *
       5                 :             :  * Redistribution and use in source and binary forms, with or without
       6                 :             :  * modification, are permitted provided that the following conditions
       7                 :             :  * are met:
       8                 :             :  * 1. Redistributions of source code must retain the above copyright
       9                 :             :  *    notice, this list of conditions and the following disclaimer.
      10                 :             :  * 2. Redistributions in binary form must reproduce the above copyright
      11                 :             :  *    notice, this list of conditions and the following disclaimer in the
      12                 :             :  *    documentation and/or other materials provided with the distribution.
      13                 :             :  *
      14                 :             :  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
      15                 :             :  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
      16                 :             :  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
      17                 :             :  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
      18                 :             :  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
      19                 :             :  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
      20                 :             :  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
      21                 :             :  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
      22                 :             :  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
      23                 :             :  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
      24                 :             :  * SUCH DAMAGE.
      25                 :             :  */
      26                 :             : 
      27                 :             : #include "cdefs-compat.h"
      28                 :             : //__FBSDID("$FreeBSD: src/lib/msun/src/k_expf.c,v 1.1 2011/10/21 06:27:56 das Exp $");
      29                 :             : 
      30                 :             : #include <openlibm_complex.h>
      31                 :             : #include <openlibm_math.h>
      32                 :             : 
      33                 :             : #include "math_private.h"
      34                 :             : 
      35                 :             : static const u_int32_t k = 235;                 /* constant for reduction */
      36                 :             : static const float kln2 =  162.88958740F;       /* k * ln2 */
      37                 :             : 
      38                 :             : /*
      39                 :             :  * See k_exp.c for details.
      40                 :             :  *
      41                 :             :  * Input:  ln(FLT_MAX) <= x < ln(2 * FLT_MAX / FLT_MIN_DENORM) ~= 192.7
      42                 :             :  * Output: 2**127 <= y < 2**128
      43                 :             :  */
      44                 :             : static float
      45                 :           0 : __frexp_expf(float x, int *expt)
      46                 :             : {
      47                 :             :         double exp_x;
      48                 :             :         u_int32_t hx;
      49                 :             : 
      50                 :           0 :         exp_x = expf(x - kln2);
      51                 :           0 :         GET_FLOAT_WORD(hx, exp_x);
      52                 :           0 :         *expt = (hx >> 23) - (0x7f + 127) + k;
      53                 :           0 :         SET_FLOAT_WORD(exp_x, (hx & 0x7fffff) | ((0x7f + 127) << 23));
      54                 :           0 :         return (exp_x);
      55                 :             : }
      56                 :             : 
      57                 :             : OLM_DLLEXPORT float
      58                 :           0 : __ldexp_expf(float x, int expt)
      59                 :             : {
      60                 :             :         float exp_x, scale;
      61                 :             :         int ex_expt;
      62                 :             : 
      63                 :           0 :         exp_x = __frexp_expf(x, &ex_expt);
      64                 :           0 :         expt += ex_expt;
      65                 :           0 :         SET_FLOAT_WORD(scale, (0x7f + expt) << 23);
      66                 :           0 :         return (exp_x * scale);
      67                 :             : }
      68                 :             : 
      69                 :             : OLM_DLLEXPORT float complex
      70                 :           0 : __ldexp_cexpf(float complex z, int expt)
      71                 :             : {
      72                 :             :         float x, y, exp_x, scale1, scale2;
      73                 :             :         int ex_expt, half_expt;
      74                 :             : 
      75                 :           0 :         x = crealf(z);
      76                 :           0 :         y = cimagf(z);
      77                 :           0 :         exp_x = __frexp_expf(x, &ex_expt);
      78                 :           0 :         expt += ex_expt;
      79                 :             : 
      80                 :           0 :         half_expt = expt / 2;
      81                 :           0 :         SET_FLOAT_WORD(scale1, (0x7f + half_expt) << 23);
      82                 :           0 :         half_expt = expt - half_expt;
      83                 :           0 :         SET_FLOAT_WORD(scale2, (0x7f + half_expt) << 23);
      84                 :             : 
      85                 :           0 :         return (CMPLXF(cosf(y) * exp_x * scale1 * scale2,
      86                 :             :             sinf(y) * exp_x * scale1 * scale2));
      87                 :             : }