| /* |
| * IBM Accurate Mathematical Library |
| * written by International Business Machines Corp. |
| * Copyright (C) 2001-2014 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: mpatan2.c */ |
| /* */ |
| /* FUNCTIONS:mpatan2 */ |
| /* */ |
| /* FILES NEEDED: mpa.h */ |
| /* mpa.c mpatan.c mpsqrt.c */ |
| /* */ |
| /* Multi-Precision Atan2(y,x) function subroutine, */ |
| /* for precision p >= 4. */ |
| /* y=0 is not permitted if x<=0. No error messages are given. */ |
| /* The relative error of the result is bounded by 44.84*r**(1-p) */ |
| /* if x <= 0, y != 0 and by 37.33*r**(1-p) if x>0. here r=2**24. */ |
| /* */ |
| /******************************************************************/ |
| |
| #include "mpa.h" |
| |
| #ifndef SECTION |
| # define SECTION |
| #endif |
| |
| /* Multi-Precision Atan2 (y, x) function subroutine, for p >= 4. |
| y = 0 is not permitted if x <= 0. No error messages are given. */ |
| void |
| SECTION |
| __mpatan2 (mp_no *y, mp_no *x, mp_no *z, int p) |
| { |
| mp_no mpt1, mpt2, mpt3; |
| |
| if (X[0] <= 0) |
| { |
| __dvd (x, y, &mpt1, p); |
| __mul (&mpt1, &mpt1, &mpt2, p); |
| if (mpt1.d[0] != 0) |
| mpt1.d[0] = 1; |
| __add (&mpt2, &mpone, &mpt3, p); |
| __mpsqrt (&mpt3, &mpt2, p); |
| __add (&mpt1, &mpt2, &mpt3, p); |
| mpt3.d[0] = Y[0]; |
| __mpatan (&mpt3, &mpt1, p); |
| __add (&mpt1, &mpt1, z, p); |
| } |
| else |
| { |
| __dvd (y, x, &mpt1, p); |
| __mpatan (&mpt1, z, p); |
| } |
| } |