From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH V3 13/26] csky: Library functions Date: Thu, 6 Sep 2018 16:24:59 +0200 Message-ID: References: <37f9bd824ede529fdab291a40eef3415f99ec8aa.1536138304.git.ren_guo@c-sky.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: <37f9bd824ede529fdab291a40eef3415f99ec8aa.1536138304.git.ren_guo@c-sky.com> Sender: linux-kernel-owner@vger.kernel.org To: Guo Ren Cc: linux-arch , Linux Kernel Mailing List , Thomas Gleixner , Daniel Lezcano , Jason Cooper , c-sky_gcc_upstream@c-sky.com, gnu-csky@mentor.com, Thomas Petazzoni , wbx@uclibc-ng.org, Greentime Hu List-Id: linux-arch.vger.kernel.org On Wed, Sep 5, 2018 at 2:08 PM Guo Ren wrote: > --- /dev/null > +++ b/arch/csky/abiv1/memset.c > @@ -0,0 +1,38 @@ > +// SPDX-License-Identifier: GPL-2.0 > +// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. > +#include > + > +void *memset(void *dest, int c, size_t l) > +{ > + char *d = dest; > + int ch = c; > + int tmp; > + > + if ((long)d & 0x3) > + while (l--) *d++ = ch; > + else { > + ch &= 0xff; > + tmp = (ch | ch << 8 | ch << 16 | ch << 24); > + > + while (l >= 16) { > + *(((long *)d)) = tmp; > + *(((long *)d)+1) = tmp; > + *(((long *)d)+2) = tmp; > + *(((long *)d)+3) = tmp; > + l -= 16; > + d += 16; > + } > + > + while (l > 3) { > + *(((long *)d)) = tmp; > + d = d + 4; > + l -= 4; > + } > + > + while (l) { > + *d++ = ch; > + l--; > + } > + } > + return dest; > +} I see that we have a trivial memset() implementation in lib/string.c, but yours seems to be better optimized. Where did you get it from? Is this a version that works particularly well on C-Sky, or is this a generic optimized memset that others could use as well? In the latter case, we could add it to lib/string.c and let architectures select it in place of the triivial version. Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f179.google.com ([209.85.216.179]:39165 "EHLO mail-qt0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729073AbeIFTBD (ORCPT ); Thu, 6 Sep 2018 15:01:03 -0400 MIME-Version: 1.0 References: <37f9bd824ede529fdab291a40eef3415f99ec8aa.1536138304.git.ren_guo@c-sky.com> In-Reply-To: <37f9bd824ede529fdab291a40eef3415f99ec8aa.1536138304.git.ren_guo@c-sky.com> From: Arnd Bergmann Date: Thu, 6 Sep 2018 16:24:59 +0200 Message-ID: Subject: Re: [PATCH V3 13/26] csky: Library functions Content-Type: text/plain; charset="UTF-8" Sender: linux-arch-owner@vger.kernel.org List-ID: To: Guo Ren Cc: linux-arch , Linux Kernel Mailing List , Thomas Gleixner , Daniel Lezcano , Jason Cooper , c-sky_gcc_upstream@c-sky.com, gnu-csky@mentor.com, Thomas Petazzoni , wbx@uclibc-ng.org, Greentime Hu Message-ID: <20180906142459.pn6NPDzEXA9cdasUQMjkf8tZ21BU96euXJukeKMg4fM@z> On Wed, Sep 5, 2018 at 2:08 PM Guo Ren wrote: > --- /dev/null > +++ b/arch/csky/abiv1/memset.c > @@ -0,0 +1,38 @@ > +// SPDX-License-Identifier: GPL-2.0 > +// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. > +#include > + > +void *memset(void *dest, int c, size_t l) > +{ > + char *d = dest; > + int ch = c; > + int tmp; > + > + if ((long)d & 0x3) > + while (l--) *d++ = ch; > + else { > + ch &= 0xff; > + tmp = (ch | ch << 8 | ch << 16 | ch << 24); > + > + while (l >= 16) { > + *(((long *)d)) = tmp; > + *(((long *)d)+1) = tmp; > + *(((long *)d)+2) = tmp; > + *(((long *)d)+3) = tmp; > + l -= 16; > + d += 16; > + } > + > + while (l > 3) { > + *(((long *)d)) = tmp; > + d = d + 4; > + l -= 4; > + } > + > + while (l) { > + *d++ = ch; > + l--; > + } > + } > + return dest; > +} I see that we have a trivial memset() implementation in lib/string.c, but yours seems to be better optimized. Where did you get it from? Is this a version that works particularly well on C-Sky, or is this a generic optimized memset that others could use as well? In the latter case, we could add it to lib/string.c and let architectures select it in place of the triivial version. Arnd