Shawn Haggett wrote:
There's two points that come to mind.1) mtune is a request for the compiler to make the code more suited to the given processor, but without breaking compatibility. march is telling the compiler, do everything you can to make this code fastest on this processor.From the GCC docs for 4.2.3:"-mtune=cpu-type: Tune to cpu-type everything applicable about the generated code, except for the ABI and the set of available instructions." "-march=cpu-type: Generate instructions for the machine type cpu-type. The choices for cpu-type are the same as for -mtune. Moreover, specifying -march=cpu-type implies -mtune=cpu-type."So mtune shouldn't be using any instructions that are in K-6 that weren't in a 386.2) I believe x86 hardware never goes backwards. That is, if a new feature is added, all future versions of the chip have that feature, just with more added. Of course Intel and AMD both have their separate additions, but since your staying with AMD, moving to a new processor shouldn't break anything (even if you had used march).Disclaimer: I'm not an expert on hardware architectures or compilers, so I might be wrong.Shawn
Thanks Shawn, that's probably the best answer I'm going to get, I doubt many of the AMD chip designers hang around here... :)
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