All of lore.kernel.org
 help / color / mirror / Atom feed
From: Thiemo Seufer <ths@networkno.de>
To: Blue Swirl <blauwirbel@gmail.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH, RFC] Fix softfloat NaN handling
Date: Wed, 9 May 2007 16:26:02 +0100	[thread overview]
Message-ID: <20070509152602.GB29867@networkno.de> (raw)
In-Reply-To: <f43fc5580705090817j30e9c289v4ee7c90968f0c36e@mail.gmail.com>

Blue Swirl wrote:
> On 5/9/07, Thiemo Seufer <ths@networkno.de> wrote:
> >Hello All,
> >
> >The relevant IEEE standards don't define if a set or a clear bit is
> >used to distinguish between QNaN and SNaN. MIPS, and apparently
> >PA RISC, made a different choice than the rest of the industry.
> 
> On Sparc, the rule is as follows:
> 
> SNaN: sign undefined,  exponent 255, mantissa  0xxx...and at least one
> bit must be nonzero
> QNaN: sign undefined, exponent 255,  mantissa 1xxx...
> 
> Is this the same as MIPS?

For MIPS, and allegedly HPPA, the meaning of the highest bit in the
mantissa is inverted. IOW, 0xxx... is a QNaN, 1xxx... is a SNaN.
The rest is the same, and AFAIK mandated by the standard.


Thiemo

      reply	other threads:[~2007-05-09 15:38 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-05-09 13:20 [Qemu-devel] [PATCH, RFC] Fix softfloat NaN handling Thiemo Seufer
2007-05-09 15:17 ` Blue Swirl
2007-05-09 15:26   ` Thiemo Seufer [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20070509152602.GB29867@networkno.de \
    --to=ths@networkno.de \
    --cc=blauwirbel@gmail.com \
    --cc=qemu-devel@nongnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.