From: Al Viro <viro@ZenIV.linux.org.uk>
To: Richard Henderson <rth@twiddle.net>
Cc: Peter Maydell <peter.maydell@linaro.org>,
QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [RFC] alpha qemu arithmetic exceptions
Date: Sat, 5 Jul 2014 06:26:07 +0100 [thread overview]
Message-ID: <20140705052607.GW18016@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20140705014055.GV18016@ZenIV.linux.org.uk>
On Sat, Jul 05, 2014 at 02:40:55AM +0100, Al Viro wrote:
> d) at least on EV6 and EV67 DNOD *still* trips INV. According to the
> manual suppression of INV by DNOD is optional. And while their text
> might be interpreted as "INV is suppressed if operation with denorm
> wouldn't result in something unpleasant" (which would apply to
> sqrt(DBL_MIN/2)), the same behaviour happens on DBL_MIN/2 + DBL_MIN/2,
> where the result is a good finite value, so it really looks like DNOD
> doesn't suppress INV at all on these processors.
>
> Does anybody have 21364 to run some tests on?
In fact, DNOD is simply not implemented on those guys - if you try to set it,
the bit still reads zero. Worse, according to Compiler Writer's Guide for the
21264/21364, "Alpha architecture FPCR bit 47 (DNOD) is not implemented
by the 21264 or 21364".
In other words, it looks like FPCR.DNOD is something from (never-produced)
21464.
next prev parent reply other threads:[~2014-07-05 5:26 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
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 [this message]
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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