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1f159eaab0
This is a nice speedup for WindowServer. I'll eventually have to do this with SSE but the kernel doesn't support SSE yet so this is it for now.
50 lines
1.5 KiB
C++
50 lines
1.5 KiB
C++
#include <AK/StdLibExtras.h>
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#include <AK/Assertions.h>
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#include <AK/Types.h>
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#include <AK/kstdio.h>
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void* mmx_memcpy(void* dest, const void* src, size_t len)
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{
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ASSERT(len >= 1024);
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auto* dest_ptr = (byte*)dest;
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auto* src_ptr = (const byte*)src;
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if ((dword)dest_ptr & 7) {
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dword prologue = 8 - ((dword)dest_ptr & 7);
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asm volatile(
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"rep movsb\n"
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:: "S"(src_ptr), "D"(dest_ptr), "c"(prologue)
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: "memory"
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);
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len -= prologue;
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}
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for (dword i = len / 64; i; --i) {
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asm volatile(
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"movq (%0), %%mm0\n"
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"movq 8(%0), %%mm1\n"
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"movq 16(%0), %%mm2\n"
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"movq 24(%0), %%mm3\n"
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"movq 32(%0), %%mm4\n"
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"movq 40(%0), %%mm5\n"
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"movq 48(%0), %%mm6\n"
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"movq 56(%0), %%mm7\n"
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"movq %%mm0, (%1)\n"
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"movq %%mm1, 8(%1)\n"
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"movq %%mm2, 16(%1)\n"
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"movq %%mm3, 24(%1)\n"
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"movq %%mm4, 32(%1)\n"
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"movq %%mm5, 40(%1)\n"
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"movq %%mm6, 48(%1)\n"
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"movq %%mm7, 56(%1)\n"
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:: "r" (src_ptr), "r" (dest_ptr) : "memory");
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src_ptr += 64;
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dest_ptr += 64;
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}
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asm volatile("emms":::"memory");
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// Whatever remains we'll have to memcpy.
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len %= 64;
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if (len)
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memcpy(dest_ptr, src_ptr, len);
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return dest;
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}
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