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author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-01-23 18:34:03 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-01-23 18:34:03 -0800 |
commit | f341535193c338b4ce4af8e32be51e6aae7f22a6 (patch) | |
tree | d054a10be84681b93ce53c348cde0d764e1e24a2 /arch/arm/include/asm/bitops.h | |
parent | 13c789a6b219aa23f917466c7e630566106b14c2 (diff) | |
parent | 857989a7fdd2f6de42272578b8aaa413ed6e63e4 (diff) | |
download | linux-f341535193c338b4ce4af8e32be51e6aae7f22a6.tar.bz2 |
Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm
Pull ARM updates from Russell King:
"In this set, we have:
- Refactoring of some of the old StrongARM-1100 GPIO code to make
things simpler by Dmitry Eremin-Solenikov
- Read-only and non-executable support for modules on ARM from Laura
Abbot
- Removal of unnecessary set_drvdata() calls in AMBA code
- Some non-executable support for kernel lowmem mappings at the 1MB
section granularity, and dumping of kernel page tables via debugfs
- Some improvements for the timer/clock code on Footbridge platforms,
and cleanup some of the LED code there
- Fix fls/ffs() signatures to match x86 to prevent build warnings,
particularly where these are used with min/max() macros
- Avoid using the bootmem allocator on ARM (patches from Santosh
Shilimkar)
- Various asid/unaligned access updates from Will Deacon"
* 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (51 commits)
ARM: SMP implementations are not supposed to return from smp_ops.cpu_die()
ARM: ignore memory below PHYS_OFFSET
Fix select-induced Kconfig warning for ZBOOT_ROM
ARM: fix ffs/fls implementations to match x86
ARM: 7935/1: sa1100: collie: add gpio-keys configuration
ARM: 7932/1: bcm: Add DEBUG_LL console support
ARM: 7929/1: Remove duplicate SCHED_HRTICK config option
ARM: 7928/1: kconfig: select HAVE_EFFICIENT_UNALIGNED_ACCESS for CPUv6+ && MMU
ARM: 7927/1: dcache: select DCACHE_WORD_ACCESS for big-endian CPUs
ARM: 7926/1: mm: flesh out and fix the comments in the ASID allocator
ARM: 7925/1: mm: keep track of last ASID allocation to improve bitmap searching
ARM: 7924/1: mm: don't bother with reserved ttbr0 when running with LPAE
ARM: PCI: add legacy IDE IRQ implementation
ARM: footbridge: cleanup LEDs code
ARM: pgd allocation: retry on failure
ARM: footbridge: add one-shot mode for DC21285 timer
ARM: footbridge: add sched_clock implementation
ARM: 7922/1: l2x0: add Marvell Tauros3 support
ARM: 7877/1: use built-in byte swap function
ARM: 7921/1: mcpm: remove redundant dsb instructions prior to sev
...
Diffstat (limited to 'arch/arm/include/asm/bitops.h')
-rw-r--r-- | arch/arm/include/asm/bitops.h | 54 |
1 files changed, 44 insertions, 10 deletions
diff --git a/arch/arm/include/asm/bitops.h b/arch/arm/include/asm/bitops.h index e691ec91e4d3..b2e298a90d76 100644 --- a/arch/arm/include/asm/bitops.h +++ b/arch/arm/include/asm/bitops.h @@ -254,25 +254,59 @@ static inline int constant_fls(int x) } /* - * On ARMv5 and above those functions can be implemented around - * the clz instruction for much better code efficiency. + * On ARMv5 and above those functions can be implemented around the + * clz instruction for much better code efficiency. __clz returns + * the number of leading zeros, zero input will return 32, and + * 0x80000000 will return 0. */ +static inline unsigned int __clz(unsigned int x) +{ + unsigned int ret; + + asm("clz\t%0, %1" : "=r" (ret) : "r" (x)); + return ret; +} + +/* + * fls() returns zero if the input is zero, otherwise returns the bit + * position of the last set bit, where the LSB is 1 and MSB is 32. + */ static inline int fls(int x) { - int ret; - if (__builtin_constant_p(x)) return constant_fls(x); - asm("clz\t%0, %1" : "=r" (ret) : "r" (x)); - ret = 32 - ret; - return ret; + return 32 - __clz(x); +} + +/* + * __fls() returns the bit position of the last bit set, where the + * LSB is 0 and MSB is 31. Zero input is undefined. + */ +static inline unsigned long __fls(unsigned long x) +{ + return fls(x) - 1; +} + +/* + * ffs() returns zero if the input was zero, otherwise returns the bit + * position of the first set bit, where the LSB is 1 and MSB is 32. + */ +static inline int ffs(int x) +{ + return fls(x & -x); +} + +/* + * __ffs() returns the bit position of the first bit set, where the + * LSB is 0 and MSB is 31. Zero input is undefined. + */ +static inline unsigned long __ffs(unsigned long x) +{ + return ffs(x) - 1; } -#define __fls(x) (fls(x) - 1) -#define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); }) -#define __ffs(x) (ffs(x) - 1) #define ffz(x) __ffs( ~(x) ) #endif |