Thanks for checking and sharing your thoughts. This is what I would expect, so at least I'm not crazy :) I really need to see the values of the registers in memmove, hopefully it's just a matter of continuing to learn gdb.
Appreciate it! Regards, Kennon > On 02/26/2026 2:50 AM PST Dimitry Andric <[email protected]> > wrote: > > > Most memcpy/memmove implementations consist of an initial part that > copies/moves any number of leading unaligned bytes, if necessary, followed by > a main loop that copies/movies the bulk as words (32 or 64 bit depending on > the architecture), and finally a part that copies/moves any number of tailing > unaligned bytes. > > The implementation you showed in assembly does just that. The main loop will > use instructions that are supposed to only be used on aligned memory, but > since the leader and trailer are handled separately, you should never run > into an alignment exception at that point. My guess is that there is some > sort of buffer overrun instead. If the overrun stays within a memory page, > you won't notice it, but unrelated data will have been clobbered. However, if > the overrun goes over a page boundary, you will get a page fault. > > -Dimitry > -- Problem reports: https://cygwin.com/problems.html FAQ: https://cygwin.com/faq/ Documentation: https://cygwin.com/docs.html Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
