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Re: [Qemu-devel] [PATCH v5 28/28] fpu/softfloat: Define floatN_silence_n
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From: |
Richard Henderson |
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Subject: |
Re: [Qemu-devel] [PATCH v5 28/28] fpu/softfloat: Define floatN_silence_nan in terms of parts_silence_nan |
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Date: |
Tue, 15 May 2018 08:41:04 -0700 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 |
On 05/15/2018 06:45 AM, Alex Bennée wrote:
>> +float64 float64_silence_nan(float64 a, float_status *status)
>> +{
>> + return float64_pack_raw(parts_silence_nan(float64_unpack_raw(a),
>> status));
>> +}
>> +
>
> Not that I'm objecting to the rationalisation but did you look at the
> code generated now we unpack NaNs? I guess NaN behaviour isn't the
> critical path for performance anyway....
Yes, I looked. It's about 5 instructions instead of 1.
But as you say, it's nowhere near critical path.
Ug. I've also just realized that the shift isn't correct though...
r~