On Wed, 29 May 2024 at 06:05, Tong Ho <tong...@amd.com> wrote: > > Add inlined functions to obtain a mask of changed bits. 3 flavors > are added: toggled, changed to 1, changed to 0. > > These newly added utilities aid common device behaviors where > actions are taken only when a register's bit(s) are changed.
Generally we would expect this kind of "add new utility functions" patch to appear in a series together with some patches which actually use the new functions. Otherwise this is all dead code. More generally: * the other bit operations in this file work on bit arrays which are arbitrary-length arrays of unsigned long, so these new functions don't fit the pattern * we have the bitops functions partly because they're inherited from the Linux kernel. The use of unsigned long works quite badly in QEMU, because for us 'long' is a type that is almost always wrong. QEMU devices usually want a type of a known length, which is either 'uint32_t' or 'uint64_t'. So I'm dubious about adding more functions that work on unsigned long. thanks -- PMM
