On Mon, 2020-06-29 at 14:26 -0600, Warner Losh wrote: > On Mon, Jun 29, 2020, 2:15 PM Ravi Pokala <rpok...@freebsd.org> > wrote: > > > -----Original Message----- > > From: <owner-src-committ...@freebsd.org> on behalf of Hans Petter > > Selasky > > <hsela...@freebsd.org> > > Date: 2020-06-29, Monday at 06:08 > > To: <src-committ...@freebsd.org>, <svn-src-...@freebsd.org>, < > > svn-src-head@freebsd.org> > > Subject: svn commit: r362781 - > > head/sys/compat/linuxkpi/common/include/linux > > > > Author: hselasky > > Date: Mon Jun 29 13:08:40 2020 > > New Revision: 362781 > > URL: https://svnweb.freebsd.org/changeset/base/362781 > > > > Log: > > Implement is_signed(), type_max() and type_min() function > > macros in > > the > > LinuxKPI. > > > > 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 Mon > > Jun 29 > > 12:59:09 2020 (r362780) > > +++ head/sys/compat/linuxkpi/common/include/linux/kernel.h Mon > > Jun 29 > > 13:08:40 2020 (r362781) > > @@ -564,4 +564,20 @@ linux_ratelimited(linux_ratelimit_t *rl) > > #define __is_constexpr(x) \ > > __builtin_constant_p(x) > > > > Hi Hans, > > > > +#define is_signed(x) (((x)-1 / (x)2) == (x)0) > > > > It took me several reads to understand this, until I figured out > > that 'x' > > is not a variable, it's the name of a *type*. > > > > If 'x' is a variable, then '(x)-1' is subtraction, but '(x)2' and > > '(x)0' > > are nonsensical. > > > > If 'x' is a *type*, then '(x)-1' is typecasting '-1', and similarly > > for > > '(x)2' and '(x)0'. > > > > So, perhaps a comment, or a better name for 'x'? > > > > I had similar thoughts. Maybe 't' instead? >
Or maybe since there's no one-character restriction on macro variable names, something actually descriptive like 'datatype'. -- Ian > Warner > > Thanks, > > > > Ravi (rpokala@) > > > > +#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) \ > > +) > > + > > +#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) \ > > +) > > + > > #endif /* _LINUX_KERNEL_H_ */ > > > > > > _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
