/* (c) Copyright 2000-2002 convergence integrated media GmbH. (c) Copyright 2002 convergence GmbH. All rights reserved. Written by Denis Oliver Kropp , Andreas Hundt and Sven Neumann . Fast memcpy code was taken from xine (see below). This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /* * Copyright (C) 2001 the xine project * * This file is part of xine, a unix video player. * * xine is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * xine is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA * * These are the MMX/MMX2/SSE optimized versions of memcpy * * This code was adapted from Linux Kernel sources by Nick Kurshev to * the mplayer program. (http://mplayer.sourceforge.net) * * Miguel Freitas split the #ifdefs into several specialized functions that * are benchmarked at runtime by xine. Some original comments from Nick * have been preserved documenting some MMX/SSE oddities. * Also added kernel memcpy function that seems faster than glibc one. * */ /* Original comments from mplayer (file: aclib.c) This part of code was taken by me from Linux-2.4.3 and slightly modified for MMX, MMX2, SSE instruction set. I have done it since linux uses page aligned blocks but mplayer uses weakly ordered data and original sources can not speedup them. Only using PREFETCHNTA and MOVNTQ together have effect! From IA-32 Intel Architecture Software Developer's Manual Volume 1, Order Number 245470: "10.4.6. Cacheability Control, Prefetch, and Memory Ordering Instructions" Data referenced by a program can be temporal (data will be used again) or non-temporal (data will be referenced once and not reused in the immediate future). To make efficient use of the processor's caches, it is generally desirable to cache temporal data and not cache non-temporal data. Overloading the processor's caches with non-temporal data is sometimes referred to as "polluting the caches". The non-temporal data is written to memory with Write-Combining semantics. The PREFETCHh instructions permits a program to load data into the processor at a suggested cache level, so that it is closer to the processors load and store unit when it is needed. If the data is already present in a level of the cache hierarchy that is closer to the processor, the PREFETCHh instruction will not result in any data movement. But we should you PREFETCHNTA: Non-temporal data fetch data into location close to the processor, minimizing cache pollution. The MOVNTQ (store quadword using non-temporal hint) instruction stores packed integer data from an MMX register to memory, using a non-temporal hint. The MOVNTPS (store packed single-precision floating-point values using non-temporal hint) instruction stores packed floating-point data from an XMM register to memory, using a non-temporal hint. The SFENCE (Store Fence) instruction controls write ordering by creating a fence for memory store operations. This instruction guarantees that the results of every store instruction that precedes the store fence in program order is globally visible before any store instruction that follows the fence. The SFENCE instruction provides an efficient way of ensuring ordering between procedures that produce weakly-ordered data and procedures that consume that data. If you have questions please contact with me: Nick Kurshev: nickols_k@mail.ru. */ /* mmx v.1 Note: Since we added alignment of destinition it speedups of memory copying on PentMMX, Celeron-1 and P2 upto 12% versus standard (non MMX-optimized) version. Note: on K6-2+ it speedups memory copying upto 25% and on K7 and P3 about 500% (5 times). */ /* Additional notes on gcc assembly and processors: [MF] prefetch is specific for AMD processors, the intel ones should be prefetch0, prefetch1, prefetch2 which are not recognized by my gcc. prefetchnta is supported both on athlon and pentium 3. therefore i will take off prefetchnta instructions from the mmx1 version to avoid problems on pentium mmx and k6-2. quote of the day: "Using prefetches efficiently is more of an art than a science" */ #ifndef __WIN32__ #include void *(*thecore_memcpy) (void * to, const void * from, size_t len) = memcpy; #endif