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Re: [Qemu-devel] [PATCH v2 1/5] target-tricore: Added FTOUZ instruction
From: |
Bastian Koppelmann |
Subject: |
Re: [Qemu-devel] [PATCH v2 1/5] target-tricore: Added FTOUZ instruction |
Date: |
Tue, 8 Nov 2016 16:12:50 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 |
On 11/08/2016 04:06 PM, Richard Henderson wrote:
> On 11/08/2016 02:37 PM, Bastian Koppelmann wrote:
>> Consider 0x836d4e86 as an input which is clearly negative, however
>> float_flag_invalid is not set. The hardware on the other hand does set
>> it.
>
> Hmm. This is -0x1.da9d0cp-121. Softfloat claims that we should round
> to zero first, and only if the result is still < 0, raise invalid.
> Which does sound plausible as a common behaviour.
TriCore does it the other way round.
>
> Does your hardware raise invalid for true -0.0, i.e. 0x80000000?
No, -0.0 does not raise invalid.
Cheers,
Bastian
[Qemu-devel] [PATCH v2 2/5] target-tricore: Added MADD.F and MSUB.F instructions, Bastian Koppelmann, 2016/11/07