On Oct 24 11:42, Christopher Faylor wrote: > On Wed, Oct 24, 2012 at 11:07:47AM -0400, Ryan Johnson wrote: > >On 24/10/2012 5:16 AM, Kai Tietz wrote: > >> Hello, > >> > >> this patch replaces the inline-assember used in string.h by C > >> implementation. > >> There are three reasons why I want to suggest this. First, the C-code > >> might > >> be optimized further by fixed (constant) arguments. Secondly, it is > >> architecture > >> independent and so we just need to maintain on code-path. And as > >> third point, by > >> inspecting generated assembly code produced by compiler out of C code > >> vs. inline-assembler > >> it shows that compiler produces better code. It handles > >> jump-threading better, and also > >> improves average executed instructions. > >Devil's advocate: better-looking code isn't always faster code. > > > >However, I'm surprised that code was inline asm in the first place -- no > >special instructions or unusual control flow -- and would not be at all > >surprised if the compiler does a better job. > > > >Also, the portability issue is relevant now that cygwin is starting the > >move toward 64-bit support. > > Yes, that's exactly why Kai is proposing this. > > I haven't looked at the code but I almost always have one response to > a "I want to rewrite a standard function" patches: > > Have you looked at other implementations? The current one was based > on a linux implementation. A C version of these functions has likely > been written before, possibly even in newlib. Were those considered?
Now that you mention it. There's strchrnul in newlib, which could simply replace strechr. There's no equivalent for ascii_strcasecmp or ascii_strncasecmp in newlib since the newlib function are multibyte capable and thus slower. Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Project Co-Leader cygwin AT cygwin DOT com Red Hat
