On 04.02.20 14:13, Segher Boessenkool wrote: > On Tue, Feb 04, 2020 at 01:41:06PM +0100, David Hildenbrand wrote: >> On 04.02.20 10:46, Oscar Salvador wrote: >>> I have to confess that it took me while to wrap around my head >>> with the new min() change, but looks ok: >> >> It's a pattern commonly used in compilers and emulators to calculate the >> number of bytes to the next block/alignment. (we're missing a macro >> (like we have ALIGN_UP/IS_ALIGNED) for that - but it's hard to come up >> with a good name (e.g., SIZE_TO_NEXT_ALIGN) . > > You can just write the easy to understand > > ... ALIGN_UP(x) - x ... you mean ALIGN_UP(x, PAGES_PER_SECTION) - x but ... > > which is better *without* having a separate name. Does that not > generate good machine code for you? 1. There is no ALIGN_UP. "SECTION_ALIGN_UP(x) - x" would be possible 2. It would be wrong if x is already aligned. e.g., let's use 4096 for simplicity as we all know that value by heart (for both x and the block size). a) -(4096 | -4096) -> 4096 b) #define ALIGN_UP(x, a) ((x + a - 1) & -(a)) ALIGN_UP(4096, 4096) - 4096 -> 0 Not as easy as it seems ... -- Thanks, David / dhildenb
