diff options
Diffstat (limited to 'src/util/bitscan.c')
-rw-r--r-- | src/util/bitscan.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/src/util/bitscan.c b/src/util/bitscan.c new file mode 100644 index 00000000000..ceca59eba98 --- /dev/null +++ b/src/util/bitscan.c @@ -0,0 +1,80 @@ +/************************************************************************** + * + * Copyright 2008 VMware, Inc. + * All Rights Reserved. + * + * 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, sub license, 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 (including the + * next paragraph) 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 NON-INFRINGEMENT. + * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS 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 "bitscan.h" + +#ifdef HAVE___BUILTIN_FFS +#elif defined(_MSC_VER) && (_M_IX86 || _M_ARM || _M_AMD64 || _M_IA64) +#else +int +ffs(unsigned i) +{ + int bit = 0; + if (!i) + return bit; + if (!(i & 0xffff)) { + bit += 16; + i >>= 16; + } + if (!(i & 0xff)) { + bit += 8; + i >>= 8; + } + if (!(i & 0xf)) { + bit += 4; + i >>= 4; + } + if (!(i & 0x3)) { + bit += 2; + i >>= 2; + } + if (!(i & 0x1)) + bit += 1; + return bit + 1; +} +#endif + +#ifdef HAVE___BUILTIN_FFSLL +#elif defined(_MSC_VER) && (_M_AMD64 || _M_ARM || _M_IA64) +#else +int +ffsll(uint64_t val) +{ + int bit; + + bit = ffs((unsigned) (val & 0xffffffff)); + if (bit != 0) + return bit; + + bit = ffs((unsigned) (val >> 32)); + if (bit != 0) + return 32 + bit; + + return 0; +} +#endif |