Date: Tue, 30 Jun 2020 08:41:34 +0000 (UTC) From: Hans Petter Selasky <hselasky@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r362794 - head/sys/compat/linuxkpi/common/include/linux Message-ID: <202006300841.05U8fYMe044989@repo.freebsd.org>
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Author: hselasky Date: Tue Jun 30 08:41:33 2020 New Revision: 362794 URL: https://svnweb.freebsd.org/changeset/base/362794 Log: Document the is_signed(), type_max() and type_min() function macros in the LinuxKPI. Try to make the function argument more readable. Suggested by: several MFC after: 1 week Sponsored by: Mellanox Technologies Modified: head/sys/compat/linuxkpi/common/include/linux/kernel.h Modified: head/sys/compat/linuxkpi/common/include/linux/kernel.h ============================================================================== --- head/sys/compat/linuxkpi/common/include/linux/kernel.h Tue Jun 30 07:37:24 2020 (r362793) +++ head/sys/compat/linuxkpi/common/include/linux/kernel.h Tue Jun 30 08:41:33 2020 (r362794) @@ -564,20 +564,33 @@ linux_ratelimited(linux_ratelimit_t *rl) #define __is_constexpr(x) \ __builtin_constant_p(x) -#define is_signed(x) (((x)-1 / (x)2) == (x)0) +/* + * The is_signed() macro below returns true if the passed data type is + * signed. Else false is returned. + */ +#define is_signed(datatype) (((datatype)-1 / (datatype)2) == (datatype)0) -#define type_max(x) ( \ - (sizeof(x) >= 8) ? (is_signed(x) ? INT64_MAX : UINT64_MAX) : \ - (sizeof(x) >= 4) ? (is_signed(x) ? INT32_MAX : UINT32_MAX) : \ - (sizeof(x) >= 2) ? (is_signed(x) ? INT16_MAX : UINT16_MAX) : \ - (is_signed(x) ? INT8_MAX : UINT8_MAX) \ +/* + * The type_max() macro below returns the maxium positive value the + * passed data type can hold. + */ +#define type_max(datatype) ( \ + (sizeof(datatype) >= 8) ? (is_signed(datatype) ? INT64_MAX : UINT64_MAX) : \ + (sizeof(datatype) >= 4) ? (is_signed(datatype) ? INT32_MAX : UINT32_MAX) : \ + (sizeof(datatype) >= 2) ? (is_signed(datatype) ? INT16_MAX : UINT16_MAX) : \ + (is_signed(datatype) ? INT8_MAX : UINT8_MAX) \ ) -#define type_min(x) ( \ - (sizeof(x) >= 8) ? (is_signed(x) ? INT64_MIN : 0) : \ - (sizeof(x) >= 4) ? (is_signed(x) ? INT32_MIN : 0) : \ - (sizeof(x) >= 2) ? (is_signed(x) ? INT16_MIN : 0) : \ - (is_signed(x) ? INT8_MIN : 0) \ +/* + * The type_min() macro below returns the minimum value the passed + * data type can hold. For unsigned types the minimum value is always + * zero. For signed types it may vary. + */ +#define type_min(datatype) ( \ + (sizeof(datatype) >= 8) ? (is_signed(datatype) ? INT64_MIN : 0) : \ + (sizeof(datatype) >= 4) ? (is_signed(datatype) ? INT32_MIN : 0) : \ + (sizeof(datatype) >= 2) ? (is_signed(datatype) ? INT16_MIN : 0) : \ + (is_signed(datatype) ? INT8_MIN : 0) \ ) #endif /* _LINUX_KERNEL_H_ */
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