Messages in this thread | | | Subject | Re: [PATCH] optimize ia32 memmove | From | Jeremy Fitzhardinge <> | Date | Tue, 30 Dec 2003 02:17:59 -0800 |
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On Tue, 2003-12-30 at 01:58, Linus Torvalds wrote: > But then anything that does the loads in ascending order is still ok, so > it shouldn't matter - by the time "dest" has been overwritten, the source > data has already been read. And all the "memcpy()" implementations had > better do that anyway, in order to get nice memory access patterns. "rep > movsl" certainly does.
A PPC memcpy may end up clearing the destination before reading the source (using the cache-line zeroing instruction, to prevent the destination from being spuriously read to populate the cache line).
J
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