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Date: Fri, 12 Nov 2010 23:08:22 +0000
Message-ID: <AANLkTi=JXaooWxo2PRJg6yrmdbDexxjA2SsmfsdRUQwe@mail.gmail.com>
Subject: Re: [Qemu-devel] [PATCH 4/8] ARM: Return correct result for
	float-to-integer conversion of NaN
From: Peter Maydell <peter.maydell@linaro.org>
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To: Nathan Froyd <froydnj@codesourcery.com>
Cc: qemu-devel@nongnu.org

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