From: Richard Henderson <rth@twiddle.net>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Peter Maydell <peter.maydell@linaro.org>,
QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [RFC] alpha qemu arithmetic exceptions
Date: Wed, 02 Jul 2014 08:26:53 -0700 [thread overview]
Message-ID: <53B424BD.6070705@twiddle.net> (raw)
In-Reply-To: <20140702061723.GM18016@ZenIV.linux.org.uk>
On 07/01/2014 11:17 PM, Al Viro wrote:
> If we don't want FE_INEXACT seen by fetestexcept() after rounding 4.5, we'd
> better not use FPCR.INE - *all* variants of actual hardware (at least from
> 21064A to 21264) set that sucker, and 4.7 in Architecture Reference Manual
> very clearly requires such behaviour for any subset that isn't completely
> without floating point support.
Um, where do you see that? I see:
# 4.7.6.4 IEEE-Compliant Arithmetic Without Inexact Exception
# This model is similar to the model in Section 4.7.6.3, except this
# model does not signal inexact results either by the inexact status
# flag or by trapping. [...] This model is implemented by using IEEE
# floating-point instructions with the /SU or /SV trap qualifiers.
The important words to me being "does not signal" and "inexact status flag".
Thus in sysdeps/alpha/fpu/s_nearbyint.c I explicitly use cvttq/svd and not
cvttq/svid. By my reading that means no inexact shall be raised.
r~
next prev parent reply other threads:[~2014-07-02 15:27 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-24 4:34 [Qemu-devel] [RFC] alpha qemu arithmetic exceptions Al Viro
2014-06-24 16:52 ` Al Viro
2014-06-24 18:33 ` Richard Henderson
2014-06-24 20:32 ` Al Viro
2014-06-24 20:57 ` Richard Henderson
2014-06-24 21:24 ` Al Viro
2014-06-24 21:32 ` Richard Henderson
2014-06-25 7:01 ` Al Viro
2014-06-25 9:27 ` Peter Maydell
2014-06-25 14:26 ` Al Viro
2014-06-25 17:41 ` Peter Maydell
2014-06-26 5:55 ` Al Viro
2014-06-30 18:39 ` Richard Henderson
2014-06-30 20:56 ` Al Viro
2014-07-01 4:34 ` Al Viro
2014-07-01 5:00 ` Al Viro
2014-07-01 14:31 ` Richard Henderson
2014-07-01 17:03 ` Richard Henderson
2014-07-01 17:50 ` Al Viro
2014-07-01 18:23 ` Peter Maydell
2014-07-01 18:30 ` Richard Henderson
2014-07-01 19:08 ` Peter Maydell
2014-07-02 4:05 ` Al Viro
2014-07-02 5:50 ` Al Viro
2014-07-02 6:17 ` Al Viro
2014-07-02 15:26 ` Richard Henderson [this message]
2014-07-02 15:49 ` Al Viro
2014-07-02 14:59 ` Richard Henderson
2014-07-02 15:20 ` Al Viro
2014-07-03 6:51 ` Al Viro
2014-07-03 18:25 ` Al Viro
2014-07-03 20:19 ` Richard Henderson
2014-07-03 22:47 ` Al Viro
2014-07-03 23:05 ` Peter Maydell
2014-07-03 23:22 ` Al Viro
2014-07-04 0:50 ` Al Viro
2014-07-04 4:30 ` Richard Henderson
2014-07-04 7:29 ` Al Viro
2014-07-05 1:40 ` Al Viro
2014-07-05 5:26 ` Al Viro
2014-07-05 21:09 ` Al Viro
2014-07-05 22:55 ` Al Viro
2014-07-07 14:11 ` Richard Henderson
2014-07-07 15:06 ` Al Viro
2014-07-07 16:20 ` Richard Henderson
2014-07-08 4:20 ` Al Viro
2014-07-08 6:03 ` Richard Henderson
2014-07-08 6:54 ` Al Viro
2014-07-08 7:13 ` Al Viro
2014-07-08 8:05 ` Peter Maydell
2014-07-08 14:53 ` Richard Henderson
2014-07-08 16:13 ` Al Viro
2014-07-08 16:33 ` Peter Maydell
2014-07-08 17:20 ` Al Viro
2014-07-08 19:32 ` Peter Maydell
2014-07-08 20:12 ` Al Viro
2014-07-09 9:19 ` Alex Bennée
2014-07-09 9:04 ` Alex Bennée
2014-07-08 18:12 ` Richard Henderson
2014-07-08 19:02 ` Al Viro
2014-07-08 19:04 ` Richard Henderson
2014-07-08 20:20 ` Al Viro
2014-07-09 4:59 ` Richard Henderson
2014-07-09 5:47 ` Al Viro
2014-07-09 15:14 ` Richard Henderson
2014-07-09 16:41 ` Al Viro
2014-06-24 18:23 ` Richard Henderson
2014-06-24 20:47 ` Al Viro
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