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? cgf
