Mathias Fröhlich | c3b6656 | 2016-06-09 06:35:34 +0200 | [diff] [blame] | 1 | /************************************************************************** |
| 2 | * |
| 3 | * Copyright 2008 VMware, Inc. |
| 4 | * All Rights Reserved. |
| 5 | * |
| 6 | * Permission is hereby granted, free of charge, to any person obtaining a |
| 7 | * copy of this software and associated documentation files (the |
| 8 | * "Software"), to deal in the Software without restriction, including |
| 9 | * without limitation the rights to use, copy, modify, merge, publish, |
| 10 | * distribute, sub license, and/or sell copies of the Software, and to |
| 11 | * permit persons to whom the Software is furnished to do so, subject to |
| 12 | * the following conditions: |
| 13 | * |
| 14 | * The above copyright notice and this permission notice (including the |
| 15 | * next paragraph) shall be included in all copies or substantial portions |
| 16 | * of the Software. |
| 17 | * |
| 18 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS |
| 19 | * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| 20 | * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. |
| 21 | * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR |
| 22 | * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, |
| 23 | * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE |
| 24 | * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| 25 | * |
| 26 | **************************************************************************/ |
| 27 | |
| 28 | |
| 29 | #include "bitscan.h" |
| 30 | |
| 31 | #ifdef HAVE___BUILTIN_FFS |
| 32 | #elif defined(_MSC_VER) && (_M_IX86 || _M_ARM || _M_AMD64 || _M_IA64) |
| 33 | #else |
| 34 | int |
Emil Velikov | a72ac98 | 2017-03-09 17:45:19 +0000 | [diff] [blame] | 35 | ffs(int i) |
Mathias Fröhlich | c3b6656 | 2016-06-09 06:35:34 +0200 | [diff] [blame] | 36 | { |
| 37 | int bit = 0; |
| 38 | if (!i) |
| 39 | return bit; |
| 40 | if (!(i & 0xffff)) { |
| 41 | bit += 16; |
| 42 | i >>= 16; |
| 43 | } |
| 44 | if (!(i & 0xff)) { |
| 45 | bit += 8; |
| 46 | i >>= 8; |
| 47 | } |
| 48 | if (!(i & 0xf)) { |
| 49 | bit += 4; |
| 50 | i >>= 4; |
| 51 | } |
| 52 | if (!(i & 0x3)) { |
| 53 | bit += 2; |
| 54 | i >>= 2; |
| 55 | } |
| 56 | if (!(i & 0x1)) |
| 57 | bit += 1; |
| 58 | return bit + 1; |
| 59 | } |
| 60 | #endif |
| 61 | |
| 62 | #ifdef HAVE___BUILTIN_FFSLL |
Erik Faye-Lund | 2f82d97 | 2019-08-14 22:29:24 +0200 | [diff] [blame] | 63 | #elif defined(_MSC_VER) && (_M_AMD64 || _M_ARM64 || _M_IA64) |
Mathias Fröhlich | c3b6656 | 2016-06-09 06:35:34 +0200 | [diff] [blame] | 64 | #else |
| 65 | int |
Emil Velikov | a72ac98 | 2017-03-09 17:45:19 +0000 | [diff] [blame] | 66 | ffsll(long long int val) |
Mathias Fröhlich | c3b6656 | 2016-06-09 06:35:34 +0200 | [diff] [blame] | 67 | { |
| 68 | int bit; |
| 69 | |
| 70 | bit = ffs((unsigned) (val & 0xffffffff)); |
| 71 | if (bit != 0) |
| 72 | return bit; |
| 73 | |
| 74 | bit = ffs((unsigned) (val >> 32)); |
| 75 | if (bit != 0) |
| 76 | return 32 + bit; |
| 77 | |
| 78 | return 0; |
| 79 | } |
| 80 | #endif |