Re: MSEC_TO_JIFFIES is messed up...

[Zan Lynx <zlynx@acm.org>]

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On Wed, 2004-05-12 at 15:12, Ingo Molnar wrote:
> * Davide Libenzi <davidel@xmailserver.org> wrote:
> 
> > int foo(int i) {
> > 
> > 
> >         return i * 1000 / 1000;
> > }
> 
> try unsigned and you'll see:
> 
>         pushl   %ebp
>         movl    %esp, %ebp
>         movl    8(%ebp), %edx
>         movl    %edx, %eax
>         sall    $2, %eax
>         addl    %edx, %eax
>         leal    0(,%eax,4), %edx
>         addl    %edx, %eax
>         leal    0(,%eax,4), %edx
>         addl    %edx, %eax
>         leal    0(,%eax,8), %edx
>         movl    $274877907, %eax
>         mull    %edx
>         movl    %edx, %eax
>         shrl    $6, %eax
>         leave
>         ret
> 
>     Ingo

Being curious, I tried that and got the same results.  But this:

int f(unsigned int x)
{
        return x * (1000 / 1000);
}

creates this:
f:
        pushl   %ebp
        movl    %esp, %ebp
        movl    8(%ebp), %eax
        leave
        ret
        .size   f, .-f
        .section        .note.GNU-stack,"",@progbits
        .ident  "GCC: (GNU) 3.3.2 20031022 (Red Hat Linux 3.3.2-1)"

-- 
Zan Lynx <zlynx@acm.org>

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