Re: [Qemu-devel] [PATCH v1 06/21] RISC-V FPU Support

[Jim Wilson]

On Wed, Jan 24, 2018 at 3:47 PM, Richard Henderson
<address@hidden> wrote:
> On 01/24/2018 10:58 AM, Jim Wilson wrote:
>> Although, looking at this again, I see another statement in a
>> different place that says:
>>
>> Except when otherwise stated, if the result of a floating-point operation is
>> NaN, it is the canonical NaN. The canonical NaN has a positive sign and all
>> significand bits clear except the MSB, a.k.a. the quiet bit. For
>> single-precision floating-point, this corresponds to the pattern
>> 0x7fc00000.
> Yes, I had read this before as well.  I had assumed that your patch 
> constituted
> an intended change to this text.
>
>> This could take a little time to sort out.
> Ok.  I don't see this as a blocking issue for merging.

So after looking at this a bit more, I've come to the conclusion that
my patch to remove the default/canonical nan support from RISC-V qemu
was wrong.  We will have to fix this on the gcc/glibc side.

Michael, please revert my change
    
https://github.com/riscv/riscv-qemu/commit/4223d89b0c5c671332d66bcd649db5c6f46559f5

Jim