Re: [Xen-devel] [PATCH v4 1/7] introduce time managment in xtf

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Mon, Apr 16, 2018 at 12:48:49PM +0200, Paul Semel wrote:
> On 04/13/2018 02:05 PM, Roger Pau Monné wrote:
> > > +static inline uint64_t scale_delta(uint64_t delta, uint32_t mul_frac, 
> > > int shift)
> > > +{
> > > +    uint64_t product;
> > > +#ifdef __i386__
> > > +    uint32_t tmp1, tmp2;
> > > +#endif
> > > +
> > > +    if ( shift < 0 )
> > > +        delta >>= -shift;
> > > +    else
> > > +        delta <<= shift;
> > > +
> > > +#ifdef __i386__
> > > +    __asm__ (
> > > +            "mul  %5       ; "
> > > +            "mov  %4,%%eax ; "
> > > +            "mov  %%edx,%4 ; "
> > > +            "mul  %5       ; "
> > > +            "add  %4,%%eax ; "
> > > +            "xor  %5,%5    ; "
> > > +            "adc  %5,%%edx ; "
> > > +            : "=A" (product), "=r" (tmp1), "=r" (tmp2)
> > > +            : "a" ((uint32_t)delta), "1" ((uint32_t)(delta >> 32)), "2" 
> > > (mul_frac) );
> > 
> > This line is too long.
> > 
> > > +#else
> > > +    __asm__ (
> > > +            "mul %%rdx ; shrd $32,%%rdx,%%rax"
> > > +            : "=a" (product) : "0" (delta), "d" ((uint64_t)mul_frac) );
> > 
> > Not sure whether you need to add a ': "d"' clobber here, since the d
> > register is used but it's not in the list of output operands.
> > 
> > > +#endif
> > > +
> > > +    return product;
> > > +}
> > > +
> 
> Actually, I'm not sure that I have to make that much changes to this
> function, as @Andrew wanted to use another version of it as far as I recall.

IMO if there are known issues with this function they need to be
sorted out before committing.

Thanks, Roger.

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