From: Rich Felker <dalias@libc.org>
To: musl@lists.openwall.com
Subject: Re: [musl] Considering x86-64 fenv.s to C
Date: Thu, 16 Jan 2020 14:33:43 -0500 [thread overview]
Message-ID: <20200116193343.GP30412@brightrain.aerifal.cx> (raw)
In-Reply-To: <alpine.LRH.2.02.2001170549410.12623@key0.esi.com.au>
On Fri, Jan 17, 2020 at 05:56:06AM +1100, Damian McGuckin wrote:
> On Thu, 16 Jan 2020, Rich Felker wrote:
>
> >As an aside, rather than implementing x86-specific C versions of
> >these, I'd like to end up with a general framework where the arch
> >just exposes a header (fenv_arch.h?) defining some primitives, and
> >the actual fenv function logic is all shared C. I'm not sure what
> >the right generalization is though. It looks like all archs have a
> >get/set exception-flags (status word) operation, but the rest
> >varies a bit.
>
> I will try and put together a summary of what things do and we can
> go from there. It will need input from somebody with way more
> expertise on ARM and RISC-V (and X87) than I.
>
> >Would you be interested in assessing what kind of abstraction makes
> >sense here?
>
> I think the abstraction might need to be consensus. Some of it is
> not even 'fenv' related. For example, some routines only ever return
> zero, while for other FPUs, the same routine can return a (-1) if
> the exception mask
> had an component (bit) which was not a valid exception.
That's one point of having the high level logic in C: not having to
repeat it in each arch where it's potentially subtly wrong. The C code
should check the validity of the mask before attempting to use the
arch primitive to set it.
Rich
next prev parent reply other threads:[~2020-01-16 19:33 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-16 4:30 Damian McGuckin
2020-01-16 15:11 ` Markus Wichmann
2020-01-16 16:14 ` Rich Felker
2020-01-16 18:56 ` Damian McGuckin
2020-01-16 19:33 ` Rich Felker [this message]
2020-01-16 21:31 ` Damian McGuckin
2020-01-17 3:36 ` Damian McGuckin
2020-01-17 3:48 ` Damian McGuckin
2020-01-17 3:53 ` David Edelsohn
2020-01-17 14:13 ` Rich Felker
2020-01-17 14:19 ` David Edelsohn
2020-01-17 14:53 ` Rich Felker
2020-01-18 4:45 ` Damian McGuckin
2020-01-18 5:29 ` Rich Felker
2020-01-19 8:50 ` Damian McGuckin
2020-01-19 9:07 ` Damian McGuckin
2020-01-19 10:42 ` Szabolcs Nagy
2020-01-19 12:25 ` Damian McGuckin
2020-01-20 5:32 ` Damian McGuckin
2020-01-20 17:38 ` Rich Felker
2020-01-20 21:11 ` [musl] Triggering Overflow (or Underflow) without triggering Inexact on i386 Damian McGuckin
2020-01-20 22:32 ` Szabolcs Nagy
2020-01-21 3:53 ` [musl] Considering x86-64 fenv.s to C Damian McGuckin
2020-01-21 4:22 ` Rich Felker
2020-01-21 4:46 ` Damian McGuckin
2020-01-21 7:26 ` Damian McGuckin
2020-01-17 16:41 ` Markus Wichmann
2020-01-18 1:15 ` Szabolcs Nagy
2020-01-18 5:03 ` Damian McGuckin
2020-01-18 5:37 ` Rich Felker
2020-01-18 9:40 ` Szabolcs Nagy
2020-01-24 0:42 ` Damian McGuckin
2020-01-24 1:11 ` Rich Felker
2020-01-24 4:13 ` Damian McGuckin
2020-01-24 4:55 ` Rich Felker
2020-01-24 6:08 ` Damian McGuckin
2020-01-24 13:44 ` Rich Felker
2020-01-24 14:45 ` Damian McGuckin
2020-01-24 23:59 ` Damian McGuckin
2020-01-25 0:11 ` Rich Felker
2020-01-26 3:28 ` Damian McGuckin
2020-01-26 3:28 ` Damian McGuckin
2020-01-26 3:30 ` Damian McGuckin
2020-01-26 3:32 ` Damian McGuckin
2020-01-26 5:25 ` Damian McGuckin
2020-01-27 3:32 ` Damian McGuckin
2020-01-27 5:39 ` Damian McGuckin
2020-02-02 0:47 ` Damian McGuckin
2020-02-03 0:54 ` Damian McGuckin
2020-02-03 2:09 ` Rich Felker
2020-02-03 2:12 ` Damian McGuckin
2020-02-22 20:17 ` Rich Felker
2020-02-22 20:53 ` Damian McGuckin
2020-02-23 5:41 ` Damian McGuckin
2020-02-23 6:25 ` Rich Felker
2020-02-23 8:35 ` Damian McGuckin
2020-02-07 21:25 ` Damian McGuckin
2020-02-07 21:38 ` Rich Felker
2020-02-07 23:53 ` Damian McGuckin
2020-02-09 5:04 ` Damian McGuckin
2020-01-24 7:10 ` Damian McGuckin
2020-01-18 5:04 ` Markus Wichmann
2020-02-03 14:16 [musl] PPC64(LE) support in musl requires ALTIVEC Romain Naour
2020-02-03 14:50 ` Rich Felker
2020-02-05 1:32 ` [musl] Considering x86-64 fenv.s to C Damian McGuckin
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