Re: [PATCH] powerpc64le: Add single instruction math functions

["A. Wilcox" <awilfox@adelielinux.org>]

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On 23/06/17 22:05, David Edelsohn wrote:
> Note that I only added the optimizations to the "powerpc64" port,
> not the "powerpc" port.  The powerpc64 port only support PPC64LE
> Linux, which does not include PPC970.  The comments about emulation
> are not relevant to the "powerpc64" port.


On 23/06/17 14:35, Rich Felker wrote:
> Indeed, musl uses the ELFv2 ABI (minus its gratuitous mandate of 
> minimum ISA level) for both little and big endian powerpc64, and I
> think we have users of both (people running it on old powerbooks,
> etc.).


These two statements contradict each other.  Also, I have made a very
minimal big-endian build of musl for the ppc64 architecture, but I
haven't had any time to test it.

There was never a 64-bit PowerPC laptop that I am aware; the highest
spec PowerPC laptop would have been a Daystar with a 32-bit MPC7448.
However, IBM, Apple, Tyan, and a few other manufacturers have released
big-endian 64-bit PowerPC hardware in both workstation and server form.

Let us also not forget that LoPAPR[1] defines (at R1-2.7-1 in my copy,
version 1.1 dated 24 March 2016) that Power Architecture platforms
"must by default operate with Big-Endian addressing".

Are you aware of any little-endian specific code in musl/powerpc64?  I
assume that libc-test would probably catch most of it when I am able
to run it, but until then, it would be nice to know if there is
anything I need to work on in the meantime.

Best,
- --arw


[1]: https://da.gd/LoPAPR

- -- 
A. Wilcox (awilfox)
Project Lead, Adélie Linux
http://adelielinux.org
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