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author | Lijun Pan <LIJUN.PAN@FREESCALE.COM> | 2014-06-20 17:17:29 (GMT) |
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committer | Tom Rini <trini@ti.com> | 2014-07-22 11:44:24 (GMT) |
commit | 8f2df5d369ea57a2c1e4697e508a86fc1346e76f (patch) | |
tree | 908ab7828c517bcd8823c9e256eb0a284c4218b6 /include | |
parent | 9d78b9ae8d39f59875607976dbdce0f6f31ed41c (diff) | |
download | u-boot-fsl-qoriq-8f2df5d369ea57a2c1e4697e508a86fc1346e76f.tar.xz |
linux/compat.h: port lower_32_bits and upper_32_bits from Linux
[backport from linux commit 204b885e and 218e180e7]
64 bit processors are becomming more and more popular.
lower_32_bits and upper_32_bits save our labor doing
shifts/manipulations like (u32)(n) and (u32)((n) >> 32).
They are good helpers in both little and big endian cases.
Port these two functions here from Linux:include/linux/kernel.h,
cater the comment message to little/big endian cases.
Later on, developers could include linux/compat.h if they want to
use these two functions.
Signed-off-by: Lijun Pan <Lijun.Pan@freescale.com>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/compat.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/compat.h b/include/linux/compat.h index 3fdfb39..35e216e 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -57,4 +57,23 @@ , __FILE__, __LINE__); } #define PAGE_SIZE 4096 + +/** + * upper_32_bits - return MSB bits 32-63 of a number if little endian, or + * return MSB bits 0-31 of a number if big endian. + * @n: the number we're accessing + * + * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress + * the "right shift count >= width of type" warning when that quantity is + * 32-bits. + */ +#define upper_32_bits(n) ((u32)(((n) >> 16) >> 16)) + +/** + * lower_32_bits - return LSB bits 0-31 of a number if little endian, or + * return LSB bits 32-63 of a number if big endian. + * @n: the number we're accessing + */ +#define lower_32_bits(n) ((u32)(n)) + #endif |