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Re: [PATCH 3/8] sparc: Rewrite everything
- From: David Miller <davem at davemloft dot net>
- To: rth at twiddle dot net
- Cc: libffi-discuss at sourceware dot org
- Date: Wed, 29 Oct 2014 16:10:58 -0400 (EDT)
- Subject: Re: [PATCH 3/8] sparc: Rewrite everything
- Authentication-results: sourceware.org; auth=none
- References: <1414525555-21256-4-git-send-email-rth at twiddle dot net> <20141029 dot 141027 dot 901195445453157818 dot davem at davemloft dot net> <545147A9 dot 9090401 at twiddle dot net>
From: Richard Henderson <rth@twiddle.net>
Date: Wed, 29 Oct 2014 13:01:45 -0700
> On 10/29/2014 11:10 AM, David Miller wrote:
>> Maybe I'm missing something?
>
> The two limits are in fact different. In gcc, see sparc_return_in_memory and
> sparc_pass_by_reference.
My bad, thanks for clarifying.
That's the only thing that caught my eye. I think for most v9 chips a
'return' is slightly more expensive than a 'ret/restore'. 'return' is
good for saving an instruction when you can put something in that
delay slot, but if you can't then you might as well do 'ret/restore'.
Series otherwise looks great, nice work!