From 048fa2df92c325cb4425dccd66c8922c8342b507 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Wed, 12 Sep 2012 22:00:53 +0100 Subject: generic: Implement generic ffs/fls using __builtin_* functions This patch implements ffs, __ffs, fls, __fls using __builtin_* gcc functions. These header files can be used by other architectures that rely on the gcc builtins. Signed-off-by: Catalin Marinas Acked-by: Arnd Bergmann --- include/asm-generic/bitops/builtin-__ffs.h | 15 +++++++++++++++ include/asm-generic/bitops/builtin-__fls.h | 15 +++++++++++++++ include/asm-generic/bitops/builtin-ffs.h | 17 +++++++++++++++++ include/asm-generic/bitops/builtin-fls.h | 16 ++++++++++++++++ 4 files changed, 63 insertions(+) create mode 100644 include/asm-generic/bitops/builtin-__ffs.h create mode 100644 include/asm-generic/bitops/builtin-__fls.h create mode 100644 include/asm-generic/bitops/builtin-ffs.h create mode 100644 include/asm-generic/bitops/builtin-fls.h (limited to 'include/asm-generic/bitops') diff --git a/include/asm-generic/bitops/builtin-__ffs.h b/include/asm-generic/bitops/builtin-__ffs.h new file mode 100644 index 000000000000..90041e3a41f0 --- /dev/null +++ b/include/asm-generic/bitops/builtin-__ffs.h @@ -0,0 +1,15 @@ +#ifndef _ASM_GENERIC_BITOPS_BUILTIN___FFS_H_ +#define _ASM_GENERIC_BITOPS_BUILTIN___FFS_H_ + +/** + * __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) +{ + return __builtin_ctzl(word); +} + +#endif diff --git a/include/asm-generic/bitops/builtin-__fls.h b/include/asm-generic/bitops/builtin-__fls.h new file mode 100644 index 000000000000..0248f386635f --- /dev/null +++ b/include/asm-generic/bitops/builtin-__fls.h @@ -0,0 +1,15 @@ +#ifndef _ASM_GENERIC_BITOPS_BUILTIN___FLS_H_ +#define _ASM_GENERIC_BITOPS_BUILTIN___FLS_H_ + +/** + * __fls - find last (most-significant) set bit in a long word + * @word: the word to search + * + * Undefined if no set bit exists, so code should check against 0 first. + */ +static __always_inline unsigned long __fls(unsigned long word) +{ + return (sizeof(word) * 8) - 1 - __builtin_clzl(word); +} + +#endif diff --git a/include/asm-generic/bitops/builtin-ffs.h b/include/asm-generic/bitops/builtin-ffs.h new file mode 100644 index 000000000000..064825829e1c --- /dev/null +++ b/include/asm-generic/bitops/builtin-ffs.h @@ -0,0 +1,17 @@ +#ifndef _ASM_GENERIC_BITOPS_BUILTIN_FFS_H_ +#define _ASM_GENERIC_BITOPS_BUILTIN_FFS_H_ + +/** + * ffs - find first bit set + * @x: the word to search + * + * This is defined the same way as + * the libc and compiler builtin ffs routines, therefore + * differs in spirit from the above ffz (man ffs). + */ +static __always_inline int ffs(int x) +{ + return __builtin_ffs(x); +} + +#endif diff --git a/include/asm-generic/bitops/builtin-fls.h b/include/asm-generic/bitops/builtin-fls.h new file mode 100644 index 000000000000..eda652d0ac7f --- /dev/null +++ b/include/asm-generic/bitops/builtin-fls.h @@ -0,0 +1,16 @@ +#ifndef _ASM_GENERIC_BITOPS_BUILTIN_FLS_H_ +#define _ASM_GENERIC_BITOPS_BUILTIN_FLS_H_ + +/** + * fls - find last (most-significant) bit set + * @x: the word to search + * + * This is defined the same way as ffs. + * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32. + */ +static __always_inline int fls(int x) +{ + return x ? sizeof(x) * 8 - __builtin_clz(x) : 0; +} + +#endif -- cgit v1.2.3 From b9034bf1e96fb8b1bf1b22ca2d3ea2aa7467e5a8 Mon Sep 17 00:00:00 2001 From: Takuya Yoshikawa Date: Thu, 4 Oct 2012 17:13:07 -0700 Subject: bitops: introduce generic {clear,set}_bit_le() Needed to replace test_and_set_bit_le() in virt/kvm/kvm_main.c which is being used for this missing function. Signed-off-by: Takuya Yoshikawa Acked-by: Arnd Bergmann Cc: Marcelo Tosatti Cc: Avi Kivity Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-generic/bitops/le.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include/asm-generic/bitops') diff --git a/include/asm-generic/bitops/le.h b/include/asm-generic/bitops/le.h index f95c663a6a41..61731543c00e 100644 --- a/include/asm-generic/bitops/le.h +++ b/include/asm-generic/bitops/le.h @@ -54,6 +54,16 @@ static inline int test_bit_le(int nr, const void *addr) return test_bit(nr ^ BITOP_LE_SWIZZLE, addr); } +static inline void set_bit_le(int nr, void *addr) +{ + set_bit(nr ^ BITOP_LE_SWIZZLE, addr); +} + +static inline void clear_bit_le(int nr, void *addr) +{ + clear_bit(nr ^ BITOP_LE_SWIZZLE, addr); +} + static inline void __set_bit_le(int nr, void *addr) { __set_bit(nr ^ BITOP_LE_SWIZZLE, addr); -- cgit v1.2.3 From aacf29bf1bf133f6219e6f8969d4ebc2ac76458f Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 13 Sep 2012 13:09:33 +0100 Subject: MPILIB: Provide count_leading/trailing_zeros() based on arch functions Provide count_leading/trailing_zeros() macros based on extant arch bit scanning functions rather than reimplementing from scratch in MPILIB. Whilst we're at it, turn count_foo_zeros(n, x) into n = count_foo_zeros(x). Also move the definition to asm-generic as other people may be interested in using it. Signed-off-by: David Howells Cc: David S. Miller Cc: Dmitry Kasatkin Cc: Arnd Bergmann Signed-off-by: Rusty Russell --- include/asm-generic/bitops/count_zeros.h | 57 ++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 include/asm-generic/bitops/count_zeros.h (limited to 'include/asm-generic/bitops') diff --git a/include/asm-generic/bitops/count_zeros.h b/include/asm-generic/bitops/count_zeros.h new file mode 100644 index 000000000000..97520d21fe62 --- /dev/null +++ b/include/asm-generic/bitops/count_zeros.h @@ -0,0 +1,57 @@ +/* Count leading and trailing zeros functions + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#ifndef _ASM_GENERIC_BITOPS_COUNT_ZEROS_H_ +#define _ASM_GENERIC_BITOPS_COUNT_ZEROS_H_ + +#include + +/** + * count_leading_zeros - Count the number of zeros from the MSB back + * @x: The value + * + * Count the number of leading zeros from the MSB going towards the LSB in @x. + * + * If the MSB of @x is set, the result is 0. + * If only the LSB of @x is set, then the result is BITS_PER_LONG-1. + * If @x is 0 then the result is COUNT_LEADING_ZEROS_0. + */ +static inline int count_leading_zeros(unsigned long x) +{ + if (sizeof(x) == 4) + return BITS_PER_LONG - fls(x); + else + return BITS_PER_LONG - fls64(x); +} + +#define COUNT_LEADING_ZEROS_0 BITS_PER_LONG + +/** + * count_trailing_zeros - Count the number of zeros from the LSB forwards + * @x: The value + * + * Count the number of trailing zeros from the LSB going towards the MSB in @x. + * + * If the LSB of @x is set, the result is 0. + * If only the MSB of @x is set, then the result is BITS_PER_LONG-1. + * If @x is 0 then the result is COUNT_TRAILING_ZEROS_0. + */ +static inline int count_trailing_zeros(unsigned long x) +{ +#define COUNT_TRAILING_ZEROS_0 (-1) + + if (sizeof(x) == 4) + return ffs(x); + else + return (x != 0) ? __ffs(x) : COUNT_TRAILING_ZEROS_0; +} + +#endif /* _ASM_GENERIC_BITOPS_COUNT_ZEROS_H_ */ -- cgit v1.2.3