| /* |
| * 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" |
| |
| __attribute__((overloadable, always_inline)) int |
| ilogb(double x) |
| { |
| ulong ux = as_ulong(x); |
| ulong ax = ux & ~SIGNBIT_DP64; |
| int r = (int)(ax >> EXPSHIFTBITS_DP64) - EXPBIAS_DP64; |
| int rs = -1011 - (int)clz(ax & MANTBITS_DP64); |
| r = ax < 0x0010000000000000UL ? rs : r; |
| r = ax > 0x7ff0000000000000UL | ax == 0UL ? 0x80000000 : r; |
| r = ax == 0x7ff0000000000000UL ? 0x7fffffff : r; |
| return r; |
| } |
| |
