2fc016c5bd
Add macros for single bit definitions of a specific type. These are similar to the BIT() macro that already exists, but with a few exceptions: 1. The namespace is such that they can be used in uapi definitions. 2. The type is set with the _AC() macro to allow it to be used in assembly. 3. The type is explicitly specified to be UL or ULL. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/n/tip-nbca8p7cg6jyjoit7klh3o91@git.kernel.org
28 lines
673 B
C
28 lines
673 B
C
/* const.h: Macros for dealing with constants. */
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#ifndef _LINUX_CONST_H
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#define _LINUX_CONST_H
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/* Some constant macros are used in both assembler and
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* C code. Therefore we cannot annotate them always with
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* 'UL' and other type specifiers unilaterally. We
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* use the following macros to deal with this.
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*
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* Similarly, _AT() will cast an expression with a type in C, but
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* leave it unchanged in asm.
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*/
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#ifdef __ASSEMBLY__
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#define _AC(X,Y) X
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#define _AT(T,X) X
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#else
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#define __AC(X,Y) (X##Y)
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#define _AC(X,Y) __AC(X,Y)
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#define _AT(T,X) ((T)(X))
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#endif
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#define _BITUL(x) (_AC(1,UL) << (x))
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#define _BITULL(x) (_AC(1,ULL) << (x))
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#endif /* !(_LINUX_CONST_H) */
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