From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Beulich" <JBeulich@suse.com>
Subject: Re: [PATCH v3 02/11] x86/intel_pstate: add some
 calculation related support
Date: Thu, 18 Jun 2015 15:07:07 +0100
Message-ID: <5582ECAB0200007800086AB5@mail.emea.novell.com>
References: <1434011189-16804-1-git-send-email-wei.w.wang@intel.com>
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To: Wei Wang <wei.w.wang@intel.com>
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>>> On 11.06.15 at 10:26, <wei.w.wang@intel.com> wrote:
> The added calculation related functions will be used in the intel_pstate.c.
> They are copied from the kernel(commit 2418f4f2, f3002134, eb18cba7).

The _Linux_ kernel I assume?

> --- a/xen/include/asm-x86/div64.h
> +++ b/xen/include/asm-x86/div64.h
> @@ -11,4 +11,76 @@
>      __rem;                                      \
>  })
>  
> +static inline uint64_t div_u64_rem(uint64_t dividend, uint32_t divisor,
> +                                      uint32_t *remainder)
> +{
> +    *remainder = do_div(dividend, divisor);
> +    return dividend;
> +}
> +
> +static inline uint64_t div_u64(uint64_t dividend, uint32_t  divisor)
> +{
> +    uint32_t remainder;
> +    return div_u64_rem(dividend, divisor, &remainder);
> +}
> +
> +/*
> + * div64_u64 - unsigned 64bit divide with 64bit divisor
> + * @dividend:    64bit dividend
> + * @divisor:    64bit divisor
> + *
> + * This implementation is a modified version of the algorithm proposed
> + * by the book 'Hacker's Delight'.  The original source and full proof
> + * can be found here and is available for use without restriction.
> + *
> + * 'http://www.hackersdelight.org/HDcode/newCode/divDouble.c.txt'
> + */
> +static inline uint64_t div64_u64(uint64_t dividend, uint64_t divisor)
> +{
> +    uint32_t high = divisor >> 32;
> +    uint64_t quot;
> +
> +    if (high == 0) {
> +        quot = div_u64(dividend, divisor);
> +    } else {

You have changed indentation to be Xen-like (and match the little
bit of code that was here before) - thanks. But once you do that,
you should fully convert to code to Xen style, i.e. (just for the
above):

    if ( high == 0 )
        quot = div_u64(dividend, divisor);
    else
    {

Jan