Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760787Ab0HFIw7 (ORCPT ); Fri, 6 Aug 2010 04:52:59 -0400 Received: from mailout2.w1.samsung.com ([210.118.77.12]:30756 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755317Ab0HFIw4 convert rfc822-to-8bit (ORCPT ); Fri, 6 Aug 2010 04:52:56 -0400 Date: Fri, 06 Aug 2010 10:54:27 +0200 From: =?utf-8?B?TWljaGHFgiBOYXphcmV3aWN6?= Subject: Re: [PATCH 2/3] lib: vsprintf: optimised put_dec() for 32-bit machines In-reply-to: <201008060935.26989.vda.linux@googlemail.com> To: Michal Nazarewicz , Denys Vlasenko Cc: linux-kernel@vger.kernel.org, "Douglas W. Jones" , Andrew Morton Message-id: Organization: Samsung Electronics MIME-version: 1.0 Content-type: text/plain; charset=utf-8; format=flowed; delsp=yes Content-transfer-encoding: 8BIT User-Agent: Opera Mail/10.60 (Linux) References: <201008060718.38345.vda.linux@googlemail.com> <87eiec9q1w.fsf@erwin.mina86.com> <201008060935.26989.vda.linux@googlemail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1527 Lines: 47 On Fri, 06 Aug 2010 09:35:26 +0200, Denys Vlasenko wrote: > On Friday 06 August 2010 09:08, Michal Nazarewicz wrote: >> >> +static noinline_for_stack >> >> +char *put_dec(char *buf, unsigned long long n) >> >> +{ >> >> + uint32_t d3, d2, d1, q; >> >> + >> >> + if (!n) { >> >> + *buf++ = '0'; >> >> + return buf; >> >> + } >> >> + >> >> + d1 = (n >> 16) & 0xFFFF; >> >> + d2 = (n >> 32) & 0xFFFF; >> >> + d3 = (n >> 48) & 0xFFFF; >> > >> > Are you assuming that sizeof(long long) == 8, always? >> >> Well... yes. C requires long long to be at least 64-bit and I don't >> see it being larger in any foreseeable feature. > > "640k will be enough for everybody"? > >> Wouldn't it be enough to put a static assert here? > > I'd prefer the code which works with arbitrarily wide long long. > If needed, use > > if (sizeof(long long) == 8) > 64-bit code > else > generic code Thanks. That seems like a perfect solution. I rearrange the code and try to post updated version after the weekend. -- Best regards, _ _ | Humble Liege of Serenely Enlightened Majesty of o' \,=./ `o | Computer Science, Michał "mina86" Nazarewicz (o o) +----[mina86*mina86.com]---[mina86*jabber.org]----ooO--(_)--Ooo-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/