Re: [Qemu-devel] [PATCH 6/9] target-xtensa: implement FP0 arithmetic

[Max Filippov]

On Sun, Sep 9, 2012 at 2:05 PM, Peter Maydell <address@hidden> wrote:
> On 9 September 2012 02:29, Max Filippov <address@hidden> wrote:
>> +float32 HELPER(abs_s)(float32 v)
>> +{
>> +    return float32_abs(v);
>> +}
>> +
>> +float32 HELPER(neg_s)(float32 v)
>> +{
>> +    return float32_chs(v);
>> +}
>
> Given that these are just 'v &= 0x7fffffff' and 'v ^= 0x80000000'
> it seems like it would be better to just generate code for them
> rather than calling out to a helper, though in some ways it does
> break the abstraction layer of the softfloat library. I've been
> toying with the idea of doing this for target-arm.

I doubt that these opcodes are used often enough to justify such
hack.

> (we could have gen_float32_abs() and gen_float32_chs() in
> softfloat.h, or would that be a worse layering violation in
> the other direction? I dunno.)

IMHO this approach is a bit cleaner.

-- 
Thanks.
-- Max