Messages in this thread | | | Date | Thu, 14 Jun 2018 16:51:37 -0500 | From | Segher Boessenkool <> | Subject | Re: [PATCH v6 3/4] powerpc/lib: implement strlen() in assembly |
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On Tue, Jun 12, 2018 at 07:01:59PM +0200, Christophe LEROY wrote: > > > Le 12/06/2018 à 16:53, Segher Boessenkool a écrit : > >On Tue, Jun 12, 2018 at 09:14:53AM +0000, Christophe Leroy wrote: > >>--- > >>Not tested on PPC64. > > > >It won't be acceptable until that happens. It also is likely quite bad > >performance on all 64-bit CPUs from the last fifteen years or so. Or you > >did nothing to prove otherwise, at least. > > Will it be as bad as the generic implementation which does it byte per > byte ?
Probably not. But how is it for short inputs, etc.?
The main point is that it needs actual testing _for correctness_.
Btw, GCC 7 and later can expand many memcmp as builtins on PowerPC (just like memset and memcpy etc.), creating better code, without function call.
Segher
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