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Diffstat (limited to 'REORG.TODO/sysdeps/ieee754/dbl-64/mptan.c')
-rw-r--r-- | REORG.TODO/sysdeps/ieee754/dbl-64/mptan.c | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/ieee754/dbl-64/mptan.c b/REORG.TODO/sysdeps/ieee754/dbl-64/mptan.c new file mode 100644 index 0000000000..6976028f8f --- /dev/null +++ b/REORG.TODO/sysdeps/ieee754/dbl-64/mptan.c @@ -0,0 +1,63 @@ +/* + * IBM Accurate Mathematical Library + * written by International Business Machines Corp. + * Copyright (C) 2001-2017 Free Software Foundation, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation; either version 2.1 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this program; if not, see <http://www.gnu.org/licenses/>. + */ +/**********************************************************************/ +/* MODULE_NAME:mptan.c */ +/* */ +/* FUNCTION: mptan */ +/* */ +/* FILES NEEDED: endian.h mpa.h */ +/* mpa.c sincos32.c branred.c */ +/* */ +/* Multi-Precision tan() function subroutine, for p=32. It is based */ +/* on the routines mpranred() and c32(). mpranred() performs range */ +/* reduction of a double number x into a multiple precision number */ +/* y, such that y=x-n*pi/2, abs(y)<pi/4, n=0,+-1,+-2,.... c32() */ +/* computes both sin(y), cos(y). tan(x) is either sin(y)/cos(y) */ +/* or -cos(y)/sin(y). The precision of the result is of about 559 */ +/* significant bits. */ +/* */ +/**********************************************************************/ +#include "endian.h" +#include "mpa.h" + +#ifndef SECTION +# define SECTION +#endif + +void +SECTION +__mptan (double x, mp_no *mpy, int p) +{ + int n; + mp_no mpw, mpc, mps; + + /* Negative or positive result. */ + n = __mpranred (x, &mpw, p) & 0x00000001; + /* Computing sin(x) and cos(x). */ + __c32 (&mpw, &mpc, &mps, p); + /* Second or fourth quarter of unit circle. */ + if (n) + { + __dvd (&mpc, &mps, mpy, p); + mpy->d[0] *= -1; + } + /* tan is negative in this area. */ + else + __dvd (&mps, &mpc, mpy, p); +} |