From: Peter Maydell <peter.maydell@linaro.org>
To: Nathan Froyd <froydnj@codesourcery.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 4/8] ARM: Return correct result for float-to-integer conversion of NaN
Date: Fri, 12 Nov 2010 23:08:22 +0000 [thread overview]
Message-ID: <AANLkTi=JXaooWxo2PRJg6yrmdbDexxjA2SsmfsdRUQwe@mail.gmail.com> (raw)
In-Reply-To: <20101111192104.GA4826@nightcrawler>
On 11 November 2010 19:21, Nathan Froyd <froydnj@codesourcery.com> wrote:
> On Thu, Nov 11, 2010 at 06:23:58PM +0000, Peter Maydell wrote:
>> The ARM architecture mandates that converting a NaN value to
>> integer gives zero. This isn't the behaviour of the SoftFloat
>> library, so NaNs must be special-cased.
>
> This is correct, but it's really only correct if FP traps are disabled.
True (in that if you take a trap you don't return any result at all),
but isn't it a bit of a red herring for this patchset given that qemu
doesn't implement trapping on FP exceptions?
I can make the commit message read "gives zero (if Invalid
Operation FP exceptions are not being trapped)" if you think
that would be clearer.
-- PMM
next prev parent reply other threads:[~2010-11-12 23:08 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-11 18:23 [Qemu-devel] [PATCH 0/8] ARM: fix VCVT instructions Peter Maydell
2010-11-11 18:23 ` [Qemu-devel] [PATCH 1/8] ARM: Fix decoding of VFP forms of VCVT between float and int/fixed Peter Maydell
2010-12-06 16:30 ` Nathan Froyd
2010-12-06 16:48 ` Peter Maydell
2010-12-06 16:57 ` Nathan Froyd
2010-12-06 17:07 ` Peter Maydell
2010-12-08 12:00 ` Peter Maydell
2010-11-11 18:23 ` [Qemu-devel] [PATCH 2/8] ARM: Fix decoding of Neon forms of VCVT between float and fixed point Peter Maydell
2010-11-11 18:23 ` [Qemu-devel] [PATCH 3/8] ARM: Fix sense of to_integer bit in Neon VCVT float/int conversion Peter Maydell
2010-11-11 18:23 ` [Qemu-devel] [PATCH 4/8] ARM: Return correct result for float-to-integer conversion of NaN Peter Maydell
2010-11-11 19:21 ` Nathan Froyd
2010-11-12 23:08 ` Peter Maydell [this message]
2010-11-11 18:23 ` [Qemu-devel] [PATCH 5/8] ARM: Return correct result for single<->double " Peter Maydell
2010-11-11 18:24 ` [Qemu-devel] [PATCH 6/8] ARM: Ignore top 16 bits when doing VCVT from 16 bit fixed point Peter Maydell
2010-11-11 18:24 ` [Qemu-devel] [PATCH 7/8] softfloat: Add float/double to 16 bit integer conversion functions Peter Maydell
2010-11-11 18:24 ` [Qemu-devel] [PATCH 8/8] ARM: Implement VCVT to 16 bit integer using new softfloat routines Peter Maydell
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