Re: mftbl in powerpc/include/cpu.h?

[Andrew Cagney <cagney%mac.com@localhost>]

> At 10:06 AM 8/10/2002, Andrew Cagney wrote:
> Andrew Cagney writes:
>
> "mftbl" is a valid simplified mnemonic.
>
> Andrew> Perhaphs, the assembler in 1.5.3 doesn't appear to support it.
>         Presumably not.  The GNU assembler has included that mnemonic
> since August 2000.
>
> Anyway, can it please be changed to ``mftb %0'' so that the kernel can be 
> compiled with either current or the 1.5.x series compiler?
>
> NO!  If you want to compile a -current kernel on 1.5.x, use build.sh to
> build yourself a -current toolchain.  Compiling with an older toolchain
> is explicitly not supported.  (-current has AltiVec support which is not
> in 1.5.x either).

Hmm, it appears that someone has gone to great lengths to ensure that 
the AltiVec code can be cleanly disabled and hence allow a basic kernel 
(with the exception of that *one* instruction! :-) to be built with the 
last stable compiler.

Even if you don't support it is there actual harm in letting people, 
within reason, keep the core kernel working with the previous compiler? 
 I figure a bit of compiler diversity is good for the kernel's health :-)

enjoy,
Andrew