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On Thu, 17 Jun 1999, Geoff Keating wrote: > > So after reading this thing one clearly gets the impression the saying > > -mcpu=i486 will affect the scheduler only, while egcs will still generate > > code that will run on i386, and -march=i486 will actually enable > > i486-specific instructions. > > > > Well, the cpp does not concur to this idea and because of this the glibc > > headers that are testing for __i486__ (like the ones that define bswap32 > > and bswap16) are getting confused. > > It would be easy for it to be confused; on powerpc, `-mcpu=601' means > produce code that runs only on 601, and `-mtune=601' means write code > that runs on any architecture but is scheduled (and so on) for the 601. > > This is in fact how it works for cpp, too; _ARCH_PWR is defined with > -mcpu=601, but not defined with -mtune=601. On the Intel -m486 is documented to do what -mtune=i486 would do, but it doesn't only that, at least the cpp gets badly confised. Anybody thinks that this is a problem? The fact that compiling against glibc headers with -m486 (which is almost everywhere in the Makefiles, btw) can result in a binary that will not run on i386, while the gcc/egcs documentation stated for years that this would not happen? Cristian -- ---------------------------------------------------------------------- Cristian Gafton -- gafton@redhat.com -- Red Hat, Inc. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ UNIX is user friendly. It's just selective about who its friends are.
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