Re: [PATCH 3/4] lib: vsprintf: Optimize put_dec_trunc8

[Michal Nazarewicz <mpn@google.com>]

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On Mon, Sep 24 2012, George Spelvin wrote:
> The fix is straightforward:
>
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index e755083..9872855 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -180,8 +180,6 @@ char *put_dec_trunc8(char *buf, unsigned r)
>  		*buf++ = q - 10*r;
>  	}
>  
> -	if (r == 0)
> -		return buf;
>  	q      = (r * 0x199a) >> 16;	/* r <= 9999 */
>  	*buf++ = (r - 10 * q)  + '0';
>  	if (q == 0)
>
> Inspired by Michal Nazarewicz, I have some ideas for more tweaking to
> that code.

Ah, right.  I also thought about that first but than started worrying
that it could produce unnecessary zeros if the loop iterates at least
once and exits with r being zero, but now I see that this cannot happen
since if the loop condition was true, r >= 10000 and it has been divided
by 10000 in the loop so now it's at least 1.

-- 
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
ooo +----<email/xmpp: mpn@google.com>--------------ooO--(_)--Ooo--

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