On Fri, 12 May 2023, Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote: > On Mon, May 08, 2023 at 10:14:02PM -0700, Lucas De Marchi wrote: >> Add GENMASK_U32(), GENMASK_U16() and GENMASK_U8() macros to create >> masks for fixed-width types and also the corresponding BIT_U32(), >> BIT_U16() and BIT_U8(). > > Why? The main reason is that GENMASK() and BIT() size varies for 32/64 bit builds. BR, Jani. > >> All of those depend on a new "U" suffix added to the integer constant. >> Due to naming clashes it's better to call the macro U32. Since C doesn't >> have a proper suffix for short and char types, the U16 and U18 variants >> just use U32 with one additional check in the BIT_* macros to make >> sure the compiler gives an error when the those types overflow. >> The BIT_U16() and BIT_U8() need the help of GENMASK_INPUT_CHECK(), >> as otherwise they would allow an invalid bit to be passed. Hence >> implement them in include/linux/bits.h rather than together with >> the other BIT* variants. > > So, we have _Generic() in case you still wish to implement this. -- Jani Nikula, Intel Open Source Graphics Center
