| /* |
| * Copyright (c) 2014 Advanced Micro Devices, Inc. |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this software and associated documentation files (the "Software"), to deal |
| * in the Software without restriction, including without limitation the rights |
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| * copies of the Software, and to permit persons to whom the Software is |
| * furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| * THE SOFTWARE. |
| */ |
| |
| #include "math64.h" |
| #include "tanD_piby4.h" |
| |
| __attribute__((overloadable)) double |
| tanpi(double x) |
| { |
| const double pi = 3.1415926535897932384626433832795; |
| |
| long ix = as_long(x); |
| long xsgn = ix & 0x8000000000000000L; |
| long xnsgn = xsgn ^ 0x8000000000000000L; |
| ix ^= xsgn; |
| double ax = as_double(ix); |
| long iax = (long)ax; |
| double r = ax - iax; |
| long xodd = xsgn ^ (iax & 0x1 ? 0x8000000000000000L : 0L); |
| |
| // Initialize with return for +-Inf and NaN |
| long ir = 0x7ff8000000000000L; |
| |
| // 2^53 <= |x| < Inf, the result is always even integer |
| ir = ix < 0x7ff0000000000000L ? xsgn : ir; |
| |
| // 2^52 <= |x| < 2^53, the result is always integer |
| ir = ix < 0x4340000000000000L ? xodd : ir; |
| |
| // 0x1.0p-14 <= |x| < 2^53, result depends on which 0.25 interval |
| |
| // r < 1.0 |
| double a = 1.0 - r; |
| int e = 0; |
| long s = xnsgn; |
| |
| // r <= 0.75 |
| int c = r <= 0.75; |
| double t = r - 0.5; |
| a = c ? t : a; |
| e = c ? 1 : e; |
| s = c ? xsgn : s; |
| |
| // r < 0.5 |
| c = r < 0.5; |
| t = 0.5 - r; |
| a = c ? t : a; |
| s = c ? xnsgn : s; |
| |
| // r <= 0.25 |
| c = r <= 0.25; |
| a = c ? r : a; |
| e = c ? 0 : e; |
| s = c ? xsgn : s; |
| |
| double api = a * pi; |
| double2 tt = tan_piby4(api, 0.0); |
| long jr = s ^ as_long(e ? tt.hi : tt.lo); |
| |
| long si = xodd | 0x7ff0000000000000L; |
| jr = r == 0.5 ? si : jr; |
| |
| ir = ix < 0x4330000000000000L ? jr : ir; |
| |
| return as_double(ir); |
| } |
| |