/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/* const.h: Macros for dealing with constants.  */

#ifndef _UAPI_LINUX_CONST_H
#define _UAPI_LINUX_CONST_H

/* Some constant macros are used in both assembler and
 * C code.  Therefore we cannot annotate them always with
 * 'UL' and other type specifiers unilaterally.  We
 * use the following macros to deal with this.
 *
 * Similarly, _AT() will cast an expression with a type in C, but
 * leave it unchanged in asm.
 */

#ifdef __ASSEMBLY__
#define _AC(X,Y)	X
#define _AT(T,X)	X
#else
#define __AC(X,Y)	(X##Y)   //把XY连接起来，输出为XY
#define _AC(X,Y)	__AC(X,Y)
#define _AT(T,X)	((T)(X))
#endif

#define _UL(x)		(_AC(x, UL))//把x变成xUL
#define _ULL(x)		(_AC(x, ULL))

#define _BITUL(x)	(_UL(1) << (x))
#define _BITULL(x)	(_ULL(1) << (x))

#endif /* _UAPI_LINUX_CONST_H */