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Re: A Far Less Ambitous Altivec patch
Alan Modra <email@example.com> writes:
> On Wed, Jan 14, 2004 at 09:50:06AM +0100, Hartmut Penner wrote:
> > I think gas supports %v0 and 0, but not v0.
> True for -mno-regnames (the default on linux). With -mregnames, you can
> also use the unadorned regs, like v0.
> > Alan, any reason, why this is this way ?
> I suppose so that you can define and use symbols that happen to look
> like a reg name.
That is a good reason. The real historical reason is that the AIX
assembler only supported 0. If you wanted to use names for registers,
you had to #include a file which defined them all. That file can be
found in gcc/config/rs6000/ppc-asm.h.
The -mregnames option, and the % prefix, can later when people writing
assembly code found this to be too irritating.