From 2dc0b9721956f4314364f68a99d8bef490870438 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Mon, 15 Dec 2014 15:07:24 -0300 Subject: tools: Move __ffs implementation to tools/include/asm-generic/bitops/__ffs.h To match the Linux kernel source code structure from where this code came from. Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: Don Zickus Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Mike Galbraith Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-gubysnp4a8hd98lxoeruak13@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/include/asm-generic/bitops/__ffs.h | 43 ++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 tools/include/asm-generic/bitops/__ffs.h (limited to 'tools/include/asm-generic') diff --git a/tools/include/asm-generic/bitops/__ffs.h b/tools/include/asm-generic/bitops/__ffs.h new file mode 100644 index 000000000000..c94175015a82 --- /dev/null +++ b/tools/include/asm-generic/bitops/__ffs.h @@ -0,0 +1,43 @@ +#ifndef _TOOLS_LINUX_ASM_GENERIC_BITOPS___FFS_H_ +#define _TOOLS_LINUX_ASM_GENERIC_BITOPS___FFS_H_ + +#include + +/** + * __ffs - find first bit in word. + * @word: The word to search + * + * Undefined if no bit exists, so code should check against 0 first. + */ +static __always_inline unsigned long __ffs(unsigned long word) +{ + int num = 0; + +#if __BITS_PER_LONG == 64 + if ((word & 0xffffffff) == 0) { + num += 32; + word >>= 32; + } +#endif + if ((word & 0xffff) == 0) { + num += 16; + word >>= 16; + } + if ((word & 0xff) == 0) { + num += 8; + word >>= 8; + } + if ((word & 0xf) == 0) { + num += 4; + word >>= 4; + } + if ((word & 0x3) == 0) { + num += 2; + word >>= 2; + } + if ((word & 0x1) == 0) + num += 1; + return num; +} + +#endif /* _TOOLS_LINUX_ASM_GENERIC_BITOPS___FFS_H_ */ -- cgit v1.2.3-59-g8ed1b