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[POWERPC] Add "is_power_of_2" checking to log2.h.

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Add the inline function "is_power_of_2()" to log2.h, where the value
zero is *not* considered to be a power of two.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Robert P. J. Day 2007-01-30 06:06:00 -05:00 committed by Paul Mackerras
parent 7df2457db8
commit 63c2f782e8
5 changed files with 13 additions and 12 deletions
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5
arch/powerpc/mm/pgtable_32.c
View File

@ -294,11 +294,8 @@ void __init mapin_ram(void)
}
}
/* is x a power of 2? */
#define is_power_of_2(x) ((x) != 0 && (((x) & ((x) - 1)) == 0))
/* is x a power of 4? */
#define is_power_of_4(x) ((x) != 0 && (((x) & (x-1)) == 0) && (ffs(x) & 1))
#define is_power_of_4(x) is_power_of_2(x) && (ffs(x) & 1))
/*
* Set up a mapping for a block of I/O.

5
arch/ppc/mm/pgtable.c
View File

@ -313,11 +313,8 @@ void __init mapin_ram(void)
}
}
/* is x a power of 2? */
#define is_power_of_2(x) ((x) != 0 && (((x) & ((x) - 1)) == 0))
/* is x a power of 4? */
#define is_power_of_4(x) ((x) != 0 && (((x) & (x-1)) == 0) && (ffs(x) & 1))
#define is_power_of_4(x) is_power_of_2(x) && (ffs(x) & 1))
/*
* Set up a mapping for a block of I/O.

2
arch/ppc/syslib/ppc85xx_rio.c
View File

@ -59,8 +59,6 @@
#define DBELL_TID(x) (*(u8 *)(x + DOORBELL_TID_OFFSET))
#define DBELL_INF(x) (*(u16 *)(x + DOORBELL_INFO_OFFSET))
#define is_power_of_2(x) (((x) & ((x) - 1)) == 0)
struct rio_atmu_regs {
u32 rowtar;
u32 pad1;

2
drivers/net/gianfar_ethtool.c
View File

@ -42,8 +42,6 @@
#include "gianfar.h"
#define is_power_of_2(x) ((x) != 0 && (((x) & ((x) - 1)) == 0))
extern void gfar_start(struct net_device *dev);
extern int gfar_clean_rx_ring(struct net_device *dev, int rx_work_limit);

11
include/linux/log2.h
View File

@ -43,6 +43,17 @@ int __ilog2_u64(u64 n)
}
#endif
/*
* Determine whether some value is a power of two, where zero is
* *not* considered a power of two.
*/
static inline __attribute__((const))
bool is_power_of_2(unsigned long n)
{
return (n != 0 && ((n & (n - 1)) == 0));
}
/*
* round up to nearest power of two
*/