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![Andreas Kling](/assets/img/avatar_default.png)
There's no great advantage to using MMX instructions here on modern processors, since REP MOVSB/STOSB are optimized in microcode anyway and tend to run much faster than MMX/SSE/AVX variants. This also makes it much easier to implement high-level emulation of memcpy/memset in UserspaceEmulator once we get there. :^)
53 lines
1.9 KiB
C
53 lines
1.9 KiB
C
/*
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* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include <AK/Types.h>
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#if defined(KERNEL)
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# include <Kernel/StdLib.h>
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#else
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# include <stdlib.h>
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# include <string.h>
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#endif
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ALWAYS_INLINE void fast_u32_copy(u32* dest, const u32* src, size_t count)
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{
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asm volatile(
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"rep movsl\n"
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: "+S"(src), "+D"(dest), "+c"(count)::"memory");
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}
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ALWAYS_INLINE void fast_u32_fill(u32* dest, u32 value, size_t count)
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{
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asm volatile(
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"rep stosl\n"
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: "=D"(dest), "=c"(count)
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: "D"(dest), "c"(count), "a"(value)
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: "memory");
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}
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