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glibc  2.9
k_tan.c
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00001 /* Copyright (C) 1996, 1997 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <math.h>
00020 #include "math_private.h"
00021 
00022 #ifndef FUNC
00023 #define FUNC tan
00024 #endif
00025 #ifndef float_type
00026 #define float_type double
00027 #endif
00028 
00029 #define __CONCATX(a,b) __CONCAT(a,b)
00030 
00031 float_type
00032 __CONCATX(__kernel_,FUNC) (x, y, iy)
00033      float_type x;
00034      float_type y;
00035      int iy;
00036 {
00037   float_type tan_x, tan_y;
00038   tan_x = __m81_u(__CONCATX(__,FUNC)) (x);
00039   tan_y = __m81_u(__CONCATX(__,FUNC)) (y);
00040   if (iy > 0)
00041     return (tan_x + tan_y) / (1 - tan_x * tan_y);
00042   else
00043     return (tan_x * tan_y - 1) / (tan_x + tan_y);
00044 }