diff options
| -rw-r--r-- | arch/s390/include/asm/bitops.h | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/arch/s390/include/asm/bitops.h b/arch/s390/include/asm/bitops.h index e5ca8598c06b..c6dbd6115cc5 100644 --- a/arch/s390/include/asm/bitops.h +++ b/arch/s390/include/asm/bitops.h @@ -307,11 +307,136 @@ unsigned long find_first_bit_left(const unsigned long *addr, unsigned long size) unsigned long find_next_bit_left(const unsigned long *addr, unsigned long size, unsigned long offset); +#ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES + +/** + * __flogr - find leftmost one + * @word - The word to search + * + * Returns the bit number of the most significant bit set, + * where the most significant bit has bit number 0. + * If no bit is set this function returns 64. + */ +static inline unsigned char __flogr(unsigned long word) +{ + if (__builtin_constant_p(word)) { + unsigned long bit = 0; + + if (!word) + return 64; + if (!(word & 0xffffffff00000000UL)) { + word <<= 32; + bit += 32; + } + if (!(word & 0xffff000000000000UL)) { + word <<= 16; + bit += 16; + } + if (!(word & 0xff00000000000000UL)) { + word <<= 8; + bit += 8; + } + if (!(word & 0xf000000000000000UL)) { + word <<= 4; + bit += 4; + } + if (!(word & 0xc000000000000000UL)) { + word <<= 2; + bit += 2; + } + if (!(word & 0x8000000000000000UL)) { + word <<= 1; + bit += 1; + } + return bit; + } else { + register unsigned long bit asm("4") = word; + register unsigned long out asm("5"); + + asm volatile( + " flogr %[bit],%[bit]\n" + : [bit] "+d" (bit), [out] "=d" (out) : : "cc"); + return bit; + } +} + +/** + * __ffs - find first bit in word. + * @word: The word to search + * + * Undefined if no bit exists, so code should check against 0 first. + */ +static inline unsigned long __ffs(unsigned long word) +{ + return __flogr(-word & word) ^ (BITS_PER_LONG - 1); +} + +/** + * ffs - find first bit set + * @word: the word to search + * + * This is defined the same way as the libc and + * compiler builtin ffs routines (man ffs). + */ +static inline int ffs(int word) +{ + unsigned long mask = 2 * BITS_PER_LONG - 1; + unsigned int val = (unsigned int)word; + + return (1 + (__flogr(-val & val) ^ (BITS_PER_LONG - 1))) & mask; +} + +/** + * __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 inline unsigned long __fls(unsigned long word) +{ + return __flogr(word) ^ (BITS_PER_LONG - 1); +} + +/** + * fls64 - find last set bit in a 64-bit word + * @word: the word to search + * + * This is defined in a similar way as the libc and compiler builtin + * ffsll, but returns the position of the most significant set bit. + * + * fls64(value) returns 0 if value is 0 or the position of the last + * set bit if value is nonzero. The last (most significant) bit is + * at position 64. + */ +static inline int fls64(unsigned long word) +{ + unsigned long mask = 2 * BITS_PER_LONG - 1; + + return (1 + (__flogr(word) ^ (BITS_PER_LONG - 1))) & mask; +} + +/** + * fls - find last (most-significant) bit set + * @word: the word to search + * + * This is defined the same way as ffs. + * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32. + */ +static inline int fls(int word) +{ + return fls64((unsigned int)word); +} + +#else /* CONFIG_HAVE_MARCH_Z9_109_FEATURES */ + #include <asm-generic/bitops/__ffs.h> #include <asm-generic/bitops/ffs.h> #include <asm-generic/bitops/__fls.h> #include <asm-generic/bitops/fls.h> #include <asm-generic/bitops/fls64.h> + +#endif /* CONFIG_HAVE_MARCH_Z9_109_FEATURES */ + #include <asm-generic/bitops/ffz.h> #include <asm-generic/bitops/find.h> #include <asm-generic/bitops/hweight.h> |