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Remove all comments deriving from Linux.

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Minor rework of ilog2() function.

Suggested by:	emaste @
Sponsored by:	Mellanox Technologies
This commit is contained in:
Hans Petter Selasky 2015-10-21 09:37:34 +00:00
parent 6f2fc610dd
commit 03ae38081c
1 changed files with 6 additions and 48 deletions
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54
sys/ofed/include/linux/log2.h
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@ -2,7 +2,7 @@
* Copyright (c) 2010 Isilon Systems, Inc.
* Copyright (c) 2010 iX Systems, Inc.
* Copyright (c) 2010 Panasas, Inc.
* Copyright (c) 2013, 2014 Mellanox Technologies, Ltd.
* Copyright (c) 2013-2015 Mellanox Technologies, Ltd.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -53,50 +53,10 @@ rounddown_pow_of_two(unsigned long x)
return (1UL << (flsl(x) - 1));
}
/*
* deal with unrepresentable constant logarithms
*/
extern __attribute__((const, noreturn))
int ____ilog2_NaN(void);
/*
* non-constant log of base 2 calculators
* - the arch may override these in asm/bitops.h if they can be implemented
* more efficiently than using fls() and fls64()
* - the arch is not required to handle n==0 if implementing the fallback
*/
#ifndef CONFIG_ARCH_HAS_ILOG2_U32
static inline __attribute__((const))
int __ilog2_u32(u32 n)
{
return flsl(n) - 1;
}
#endif
#ifndef CONFIG_ARCH_HAS_ILOG2_U64
static inline __attribute__((const))
int __ilog2_u64(u64 n)
{
return flsl(n) - 1;
}
#endif
/**
* ilog2 - log of base 2 of 32-bit or a 64-bit unsigned value
* @n - parameter
*
* constant-capable log of base 2 calculation
* - this can be used to initialise global variables from constant data, hence
* the massive ternary operator construction
*
* selects the appropriately-sized optimised version depending on sizeof(n)
*/
#define ilog2(n) \
#define ilog2(n) \
( \
__builtin_constant_p(n) ? ( \
(n) < 1 ? ____ilog2_NaN() : \
(n) < 1 ? -1 : \
(n) & (1ULL << 63) ? 63 : \
(n) & (1ULL << 62) ? 62 : \
(n) & (1ULL << 61) ? 61 : \
@ -161,12 +121,10 @@ int __ilog2_u64(u64 n)
(n) & (1ULL << 2) ? 2 : \
(n) & (1ULL << 1) ? 1 : \
(n) & (1ULL << 0) ? 0 : \
____ilog2_NaN() \
) : \
-1) : \
(sizeof(n) <= 4) ? \
__ilog2_u32(n) : \
__ilog2_u64(n) \
)
fls((u32)(n)) - 1 : flsll((u64)(n)) - 1 \
)
#define order_base_2(x) ilog2(roundup_pow_of_two(x))