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author | Jiri Kosina <jkosina@suse.cz> | 2012-04-08 21:48:52 +0200 |
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committer | Jiri Kosina <jkosina@suse.cz> | 2012-04-08 21:48:52 +0200 |
commit | e75d660672ddd11704b7f0fdb8ff21968587b266 (patch) | |
tree | ccb9c107744c10b553c0373e450bee3971d16c00 /arch/x86/include/asm/word-at-a-time.h | |
parent | 61282f37927143e45b03153f3e7b48d6b702147a (diff) | |
parent | 0034102808e0dbbf3a2394b82b1bb40b5778de9e (diff) | |
download | op-kernel-dev-e75d660672ddd11704b7f0fdb8ff21968587b266.zip op-kernel-dev-e75d660672ddd11704b7f0fdb8ff21968587b266.tar.gz |
Merge branch 'master' into for-next
Merge with latest Linus' tree, as I have incoming patches
that fix code that is newer than current HEAD of for-next.
Conflicts:
drivers/net/ethernet/realtek/r8169.c
Diffstat (limited to 'arch/x86/include/asm/word-at-a-time.h')
-rw-r--r-- | arch/x86/include/asm/word-at-a-time.h | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/arch/x86/include/asm/word-at-a-time.h b/arch/x86/include/asm/word-at-a-time.h new file mode 100644 index 0000000..6fe6767 --- /dev/null +++ b/arch/x86/include/asm/word-at-a-time.h @@ -0,0 +1,46 @@ +#ifndef _ASM_WORD_AT_A_TIME_H +#define _ASM_WORD_AT_A_TIME_H + +/* + * This is largely generic for little-endian machines, but the + * optimal byte mask counting is probably going to be something + * that is architecture-specific. If you have a reliably fast + * bit count instruction, that might be better than the multiply + * and shift, for example. + */ + +#ifdef CONFIG_64BIT + +/* + * Jan Achrenius on G+: microoptimized version of + * the simpler "(mask & ONEBYTES) * ONEBYTES >> 56" + * that works for the bytemasks without having to + * mask them first. + */ +static inline long count_masked_bytes(unsigned long mask) +{ + return mask*0x0001020304050608ul >> 56; +} + +#else /* 32-bit case */ + +/* Carl Chatfield / Jan Achrenius G+ version for 32-bit */ +static inline long count_masked_bytes(long mask) +{ + /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */ + long a = (0x0ff0001+mask) >> 23; + /* Fix the 1 for 00 case */ + return a & mask; +} + +#endif + +#define REPEAT_BYTE(x) ((~0ul / 0xff) * (x)) + +/* Return the high bit set in the first byte that is a zero */ +static inline unsigned long has_zero(unsigned long a) +{ + return ((a - REPEAT_BYTE(0x01)) & ~a) & REPEAT_BYTE(0x80); +} + +#endif /* _ASM_WORD_AT_A_TIME_H */ |