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544 lines
32 KiB
544 lines
32 KiB
4 years ago
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/*
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* memcpy.c - optimized memcpy() routines for aclib
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* Written by Andrew Church <achurch@achurch.org>
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*
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* This file is part of transcode, a video stream processing tool.
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* transcode is free software, distributable under the terms of the GNU
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* General Public License (version 2 or later). See the file COPYING
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* for details.
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*/
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#include "ac.h"
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#include "ac_internal.h"
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#include <string.h>
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/* Use memmove because memcpy isn't guaranteed to be ascending */
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static void *(*memcpy_ptr)(void *, const void *, size_t) = memmove;
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/*************************************************************************/
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/* External interface */
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void *ac_memcpy(void *dest, const void *src, size_t size)
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{
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return (*memcpy_ptr)(dest, src, size);
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}
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/*************************************************************************/
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/*************************************************************************/
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/* Note the check for ARCH_X86 here: this is to prevent compilation of this
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* code on x86_64, since all x86_64 processors support SSE2, and because
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* this code is not set up to use the 64-bit registers for addressing on
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* x86_64. */
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#if defined(HAVE_ASM_MMX) && defined(ARCH_X86)
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/* MMX-optimized routine, intended for PMMX/PII processors.
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* Nonstandard instructions used:
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* (CPUID.MMX) MOVQ
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*/
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static void *memcpy_mmx(void *dest, const void *src, size_t bytes)
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{
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asm("\
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PENTIUM_LINE_SIZE = 32 # PMMX/PII cache line size \n\
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PENTIUM_CACHE_SIZE = 8192 # PMMX/PII total cache size \n\
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# Use only half because writes may touch the cache too (PII) \n\
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PENTIUM_CACHE_BLOCK = (PENTIUM_CACHE_SIZE/2 - PENTIUM_LINE_SIZE) \n\
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\n\
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push %%ebx # Save PIC register \n\
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push %%edi # Save destination for return value \n\
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cld # MOVS* should ascend \n\
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\n\
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mov $64, %%ebx # Constant \n\
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\n\
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cmp %%ebx, %%ecx \n\
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jb mmx.memcpy_last # Just use movs if <64 bytes \n\
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\n\
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# First align destination address to a multiple of 8 bytes \n\
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mov $8, %%eax # EAX <- (8-dest) & 7 \n\
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sub %%edi, %%eax \n\
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and $7, %%eax # ... which is the number of bytes to copy\n"
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#ifdef ACLIB_DISABLE_X86_TEXTRELS // Because "lea 0f" requires a textrel
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" xchg %%eax, %%ecx \n\
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mov %%ecx, %%edx \n\
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repz movsb \n\
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mov %%eax, %%ecx \n\
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mov %%edx, %%eax \n"
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#else
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" lea 0f, %%edx # Use a computed jump--faster than a loop\n\
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sub %%eax, %%edx \n\
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jmp *%%edx # Execute 0-7 MOVSB's \n\
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movsb \n\
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movsb \n\
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movsb \n\
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movsb \n\
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movsb \n\
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movsb \n\
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movsb \n"
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#endif
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"0: sub %%eax, %%ecx # Update count \n\
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\n\
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# Now copy data in blocks \n\
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0: mov %%ecx, %%edx # EDX <- ECX >> 6 (cache lines to copy) \n\
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shr $6, %%edx \n\
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jz mmx.memcpy_last # <64 bytes left? Skip to end \n\
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cmp $PENTIUM_CACHE_BLOCK/64, %%edx \n\
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jb 1f # Limit size of block \n\
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mov $PENTIUM_CACHE_BLOCK/64, %%edx \n\
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1: mov %%edx, %%eax # EAX <- EDX << 6 (bytes to copy) \n\
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shl $6, %%eax \n\
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sub %%eax, %%ecx # Update remaining count \n\
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add %%eax, %%esi # Point to end of region to be block-copied\n\
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2: test %%eax, -32(%%esi) # Touch each cache line in reverse order\n\
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test %%eax, -64(%%esi) \n\
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sub %%ebx, %%esi # Update pointer \n\
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sub %%ebx, %%eax # And loop \n\
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jnz 2b \n\
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# Note that ESI now points to the beginning of the block \n\
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3: movq (%%esi), %%mm0 # Do the actual copy, 64 bytes at a time\n\
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movq 8(%%esi), %%mm1 \n\
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movq 16(%%esi), %%mm2 \n\
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movq 24(%%esi), %%mm3 \n\
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movq 32(%%esi), %%mm4 \n\
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movq 40(%%esi), %%mm5 \n\
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movq 48(%%esi), %%mm6 \n\
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movq 56(%%esi), %%mm7 \n\
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movq %%mm0, (%%edi) \n\
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movq %%mm1, 8(%%edi) \n\
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movq %%mm2, 16(%%edi) \n\
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movq %%mm3, 24(%%edi) \n\
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movq %%mm4, 32(%%edi) \n\
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movq %%mm5, 40(%%edi) \n\
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movq %%mm6, 48(%%edi) \n\
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movq %%mm7, 56(%%edi) \n\
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add %%ebx, %%esi # Update pointers \n\
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add %%ebx, %%edi \n\
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dec %%edx # And loop \n\
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jnz 3b \n\
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jmp 0b \n\
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\n\
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mmx.memcpy_last: \n\
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# Copy last <64 bytes, using the computed jump trick \n\
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mov %%ecx, %%eax # EAX <- ECX>>2 \n\
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shr $2, %%eax \n"
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#ifdef ACLIB_DISABLE_X86_TEXTRELS
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" xchg %%eax, %%ecx \n\
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repz movsd \n\
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mov %%eax, %%ecx \n"
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#else
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" lea 0f, %%edx \n\
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sub %%eax, %%edx \n\
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jmp *%%edx # Execute 0-15 MOVSD's \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n"
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#endif
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"0: and $3, %%ecx # ECX <- ECX & 3 \n"
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#ifdef ACLIB_DISABLE_X86_TEXTRELS
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" repz movsb \n"
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#else
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" lea 0f, %%edx \n\
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sub %%ecx, %%edx \n\
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jmp *%%edx # Execute 0-3 MOVSB's \n\
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movsb \n\
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movsb \n\
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movsb \n"
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#endif
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"0: \n\
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# All done! \n\
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emms # Clean up MMX state \n\
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pop %%edi # Restore destination (return value) \n\
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pop %%ebx # Restore PIC register \n\
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" : /* no outputs */
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: "D" (dest), "S" (src), "c" (bytes)
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: "%eax", "%edx"
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);
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return dest;
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}
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#endif /* HAVE_ASM_MMX && ARCH_X86 */
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/*************************************************************************/
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#if defined(HAVE_ASM_SSE) && defined(ARCH_X86)
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/* SSE-optimized routine. Backported from AMD64 routine below.
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* Nonstandard instructions used:
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* (CPUID.CMOVE) CMOVA
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* (CPUID.MMX) MOVQ
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* (CPUID.SSE) MOVNTQ
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*/
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static void *memcpy_sse(void *dest, const void *src, size_t bytes)
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{
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asm("\
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push %%ebx # Save PIC register \n\
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push %%edi # Save destination for return value \n\
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cld # MOVS* should ascend \n\
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\n\
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cmp $64, %%ecx # Skip block copy for small blocks \n\
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jb sse.memcpy_last \n\
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\n\
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mov $128, %%ebx # Constant used later \n\
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\n\
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# First align destination address to a multiple of 8 bytes \n\
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mov $8, %%eax # EAX <- (8-dest) & 7 \n\
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sub %%edi, %%eax \n\
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and $7, %%eax # ... which is the number of bytes to copy\n"
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#ifdef ACLIB_DISABLE_X86_TEXTRELS
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" xchg %%eax, %%ecx \n\
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mov %%ecx, %%edx \n\
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repz movsb \n\
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mov %%eax, %%ecx \n\
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mov %%edx, %%eax \n"
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#else
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" lea 0f, %%edx # Use a computed jump--faster than a loop\n\
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sub %%eax, %%edx \n\
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jmp *%%edx # Execute 0-7 MOVSB's \n\
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movsb \n\
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movsb \n\
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movsb \n\
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movsb \n\
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movsb \n\
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movsb \n\
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movsb \n"
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#endif
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"0: sub %%eax, %%ecx # Update count \n\
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\n\
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cmp $0x10040, %%ecx # Is this a large block? (0x10040 is an \n\
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# arbitrary value where prefetching and \n\
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# write combining seem to start becoming\n\
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# faster) \n\
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jae sse.memcpy_bp # Yup, use prefetch copy \n\
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\n\
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sse.memcpy_small: # Small block copy routine--no prefetch \n"
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#if 0
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" mov %%ecx, %%edx # EDX <- bytes to copy / 8 \n\
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shr $3, %%edx \n\
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mov %%edx, %%eax # Leave remainder in ECX for later \n\
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shl $3, %%eax \n\
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sub %%eax, %%ecx \n\
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.balign 16 \n\
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0: movq (%%esi), %%mm0 # Copy 8 bytes of data \n\
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movq %%mm0, (%%edi) \n\
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add $8, %%esi # Update pointers \n\
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add $8, %%edi \n\
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dec %%edx # And loop \n\
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jg 0b \n\
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jmp sse.memcpy_last # Copy any remaining bytes \n\
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\n\
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nop # Align loops below \n"
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#else
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" # It appears that a simple rep movs is faster than cleverness \n\
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# with movq... \n\
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mov %%ecx, %%edx # EDX <- ECX & 3 \n\
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and $3, %%edx \n\
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shr $2, %%ecx # ECX <- ECX >> 2 \n\
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rep movsl # Copy away! \n\
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mov %%edx, %%ecx # Take care of last 0-3 bytes \n\
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rep movsb \n\
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jmp sse.memcpy_end # And exit \n\
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\n\
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.balign 16 \n\
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nop \n\
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nop \n"
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#endif
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"sse.memcpy_bp: # Block prefetch copy routine \n\
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0: mov %%ecx, %%edx # EDX: temp counter \n\
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shr $6, %%edx # Divide by cache line size (64 bytes) \n\
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cmp %%ebx, %%edx # ... and cap at 128 (8192 bytes) \n\
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cmova %%ebx, %%edx \n\
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shl $3, %%edx # EDX <- cache lines to copy * 8 \n\
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mov %%edx, %%eax # EAX <- cache lines to preload * 8 \n\
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# (also used as memory offset) \n\
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1: test %%eax, -64(%%esi,%%eax,8) # Preload cache lines in pairs \n\
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test %%eax, -128(%%esi,%%eax,8) # (going backwards) \n\
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# (note that test %%eax,... seems to be faster than prefetchnta \n\
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# on x86) \n\
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sub $16, %%eax # And loop \n\
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jg 1b \n\
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\n\
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# Then copy--forward, which seems to be faster than reverse for \n\
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# certain alignments \n\
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xor %%eax, %%eax \n\
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2: movq (%%esi,%%eax,8), %%mm0 # Copy 8 bytes and loop \n\
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movntq %%mm0, (%%edi,%%eax,8) \n\
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inc %%eax \n\
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cmp %%edx, %%eax \n\
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jb 2b \n\
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\n\
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# Finally, update pointers and count, and loop \n\
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shl $3, %%edx # EDX <- bytes copied \n\
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add %%edx, %%esi \n\
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add %%edx, %%edi \n\
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sub %%edx, %%ecx \n\
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cmp $64, %%ecx # At least one cache line left? \n\
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jae 0b # Yup, loop \n\
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\n\
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sse.memcpy_last: \n\
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# Copy last <64 bytes, using the computed jump trick \n\
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mov %%ecx, %%eax # EAX <- ECX>>2 \n\
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shr $2, %%eax \n"
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#ifdef ACLIB_DISABLE_X86_TEXTRELS
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" xchg %%eax, %%ecx \n\
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repz movsd \n\
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mov %%eax, %%ecx \n"
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#else
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" lea 0f, %%edx \n\
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sub %%eax, %%edx \n\
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jmp *%%edx # Execute 0-15 MOVSD's \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n\
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movsd \n"
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#endif
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"0: and $3, %%ecx # ECX <- ECX & 3 \n"
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#ifdef ACLIB_DISABLE_X86_TEXTRELS
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" repz movsb \n"
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#else
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" lea sse.memcpy_end, %%edx \n\
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sub %%ecx, %%edx \n\
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jmp *%%edx # Execute 0-3 MOVSB's \n\
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movsb \n\
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movsb \n\
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movsb \n"
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#endif
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" \n\
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sse.memcpy_end: \n\
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# All done! \n\
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emms # Clean up after MMX instructions \n\
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sfence # Flush the write buffer \n\
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pop %%edi # Restore destination (return value) \n\
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pop %%ebx # Restore PIC register \n\
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" : /* no outputs */
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|
|
: "D" (dest), "S" (src), "c" (bytes)
|
||
|
|
: "%eax", "%edx"
|
||
|
|
);
|
||
|
|
return dest;
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* HAVE_ASM_SSE && ARCH_X86 */
|
||
|
|
|
||
|
|
/*************************************************************************/
|
||
|
|
|
||
|
|
#if defined(HAVE_ASM_SSE2) && defined(ARCH_X86_64)
|
||
|
|
|
||
|
|
/* AMD64-optimized routine, using SSE2. Derived from AMD64 optimization
|
||
|
|
* guide section 5.13: Appropriate Memory Copying Routines.
|
||
|
|
* Nonstandard instructions used:
|
||
|
|
* (CPUID.CMOVE) CMOVA
|
||
|
|
* (CPUID.SSE2) MOVDQA, MOVDQU, MOVNTDQ
|
||
|
|
*
|
||
|
|
* Note that this routine will also run more or less as-is (modulo register
|
||
|
|
* names and label(%%rip) references) on x86 CPUs, but tests have shown the
|
||
|
|
* SSE1 version above to be faster.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* The block copying code--macroized because we use two versions of it
|
||
|
|
* depending on whether the source is 16-byte-aligned or not. Pass either
|
||
|
|
* movdqa or movdqu (unquoted) for the parameter. */
|
||
|
|
#define AMD64_BLOCK_MEMCPY(movdq) \
|
||
|
|
" # First prefetch (note that if we end on an odd number of cache \n\
|
||
|
|
# lines, we skip prefetching the last one--faster that way than \n\
|
||
|
|
# prefetching line by line or treating it as a special case) \n\
|
||
|
|
0: mov %%ecx, %%edx # EDX: temp counter (always <32 bits) \n\
|
||
|
|
shr $6, %%edx # Divide by cache line size (64 bytes) \n\
|
||
|
|
cmp %%ebx, %%edx # ... and cap at 128 (8192 bytes) \n\
|
||
|
|
cmova %%ebx, %%edx \n\
|
||
|
|
shl $3, %%edx # EDX <- cache lines to copy * 8 \n\
|
||
|
|
mov %%edx, %%eax # EAX <- cache lines to preload * 8 \n\
|
||
|
|
# (also used as memory offset) \n\
|
||
|
|
1: prefetchnta -64(%%rsi,%%rax,8) # Preload cache lines in pairs \n\
|
||
|
|
prefetchnta -128(%%rsi,%%rax,8) # (going backwards) \n\
|
||
|
|
sub $16, %%eax # And loop \n\
|
||
|
|
jg 1b \n\
|
||
|
|
\n\
|
||
|
|
# Then copy--forward, which seems to be faster than reverse for \n\
|
||
|
|
# certain alignments \n\
|
||
|
|
xor %%eax, %%eax \n\
|
||
|
|
2: " #movdq " (%%rsi,%%rax,8), %%xmm0 # Copy 16 bytes and loop \n\
|
||
|
|
movntdq %%xmm0, (%%rdi,%%rax,8) \n\
|
||
|
|
add $2, %%eax \n\
|
||
|
|
cmp %%edx, %%eax \n\
|
||
|
|
jb 2b \n\
|
||
|
|
\n\
|
||
|
|
# Finally, update pointers and count, and loop \n\
|
||
|
|
shl $3, %%edx # EDX <- bytes copied \n\
|
||
|
|
add %%rdx, %%rsi \n\
|
||
|
|
add %%rdx, %%rdi \n\
|
||
|
|
sub %%rdx, %%rcx \n\
|
||
|
|
cmp $64, %%rcx # At least one cache line left? \n\
|
||
|
|
jae 0b # Yup, loop \n"
|
||
|
|
|
||
|
|
static void *memcpy_amd64(void *dest, const void *src, size_t bytes)
|
||
|
|
{
|
||
|
|
asm("\
|
||
|
|
push %%rdi # Save destination for return value \n\
|
||
|
|
cld # MOVS* should ascend \n\
|
||
|
|
\n\
|
||
|
|
cmp $64, %%rcx # Skip block copy for small blocks \n\
|
||
|
|
jb amd64.memcpy_last \n\
|
||
|
|
\n\
|
||
|
|
mov $128, %%ebx # Constant used later \n\
|
||
|
|
\n\
|
||
|
|
# First align destination address to a multiple of 16 bytes \n\
|
||
|
|
mov $8, %%eax # EAX <- (8-dest) & 7 \n\
|
||
|
|
sub %%edi, %%eax # (we don't care about the top 32 bits) \n\
|
||
|
|
and $7, %%eax # ... which is the number of bytes to copy\n\
|
||
|
|
lea 0f(%%rip), %%rdx # Use a computed jump--faster than a loop\n\
|
||
|
|
sub %%rax, %%rdx \n\
|
||
|
|
jmp *%%rdx # Execute 0-7 MOVSB's \n\
|
||
|
|
movsb \n\
|
||
|
|
movsb \n\
|
||
|
|
movsb \n\
|
||
|
|
movsb \n\
|
||
|
|
movsb \n\
|
||
|
|
movsb \n\
|
||
|
|
movsb \n\
|
||
|
|
0: sub %%rax, %%rcx # Update count \n\
|
||
|
|
test $8, %%edi # Is destination not 16-byte aligned? \n\
|
||
|
|
je 1f \n\
|
||
|
|
movsq # Then move 8 bytes to align it \n\
|
||
|
|
sub $8, %%rcx \n\
|
||
|
|
\n\
|
||
|
|
1: cmp $0x38000, %%rcx # Is this a large block? (0x38000 is an \n\
|
||
|
|
# arbitrary value where prefetching and \n\
|
||
|
|
# write combining seem to start becoming\n\
|
||
|
|
# faster) \n\
|
||
|
|
jb amd64.memcpy_small # Nope, use small copy (no prefetch/WC) \n\
|
||
|
|
test $15, %%esi # Is source also 16-byte aligned? \n\
|
||
|
|
# (use ESI to save a REX prefix byte) \n\
|
||
|
|
jnz amd64.memcpy_normal_bp # Nope, use slow copy \n\
|
||
|
|
jmp amd64.memcpy_fast_bp # Yup, use fast copy \n\
|
||
|
|
\n\
|
||
|
|
amd64.memcpy_small: # Small block copy routine--no prefetch \n\
|
||
|
|
mov %%ecx, %%edx # EDX <- bytes to copy / 16 \n\
|
||
|
|
shr $4, %%edx # (count known to fit in 32 bits) \n\
|
||
|
|
mov %%edx, %%eax # Leave remainder in ECX for later \n\
|
||
|
|
shl $4, %%eax \n\
|
||
|
|
sub %%eax, %%ecx \n\
|
||
|
|
.balign 16 \n\
|
||
|
|
0: movdqu (%%rsi), %%xmm0 # Copy 16 bytes of data \n\
|
||
|
|
movdqa %%xmm0, (%%rdi) \n\
|
||
|
|
add $16, %%rsi # Update pointers \n\
|
||
|
|
add $16, %%rdi \n\
|
||
|
|
dec %%edx # And loop \n\
|
||
|
|
jnz 0b \n\
|
||
|
|
jmp amd64.memcpy_last # Copy any remaining bytes \n\
|
||
|
|
\n\
|
||
|
|
.balign 16 \n\
|
||
|
|
nop \n\
|
||
|
|
nop \n\
|
||
|
|
amd64.memcpy_fast_bp: # Fast block prefetch loop \n"
|
||
|
|
AMD64_BLOCK_MEMCPY(movdqa)
|
||
|
|
" jmp amd64.memcpy_last # Copy any remaining bytes \n\
|
||
|
|
\n\
|
||
|
|
.balign 16 \n\
|
||
|
|
nop \n\
|
||
|
|
nop \n\
|
||
|
|
amd64.memcpy_normal_bp: # Normal (unaligned) block prefetch loop\n"
|
||
|
|
AMD64_BLOCK_MEMCPY(movdqu)
|
||
|
|
" \n\
|
||
|
|
amd64.memcpy_last: \n\
|
||
|
|
# Copy last <64 bytes, using the computed jump trick \n\
|
||
|
|
mov %%ecx, %%eax # EAX <- ECX>>3 \n\
|
||
|
|
shr $3, %%eax \n\
|
||
|
|
lea 0f(%%rip), %%rdx \n\
|
||
|
|
add %%eax, %%eax # Watch out, MOVSQ is 2 bytes! \n\
|
||
|
|
sub %%rax, %%rdx \n\
|
||
|
|
jmp *%%rdx # Execute 0-7 MOVSQ's \n\
|
||
|
|
movsq \n\
|
||
|
|
movsq \n\
|
||
|
|
movsq \n\
|
||
|
|
movsq \n\
|
||
|
|
movsq \n\
|
||
|
|
movsq \n\
|
||
|
|
movsq \n\
|
||
|
|
0: and $7, %%ecx # ECX <- ECX & 7 \n\
|
||
|
|
lea 0f(%%rip), %%rdx \n\
|
||
|
|
sub %%rcx, %%rdx \n\
|
||
|
|
jmp *%%rdx # Execute 0-7 MOVSB's \n\
|
||
|
|
movsb \n\
|
||
|
|
movsb \n\
|
||
|
|
movsb \n\
|
||
|
|
movsb \n\
|
||
|
|
movsb \n\
|
||
|
|
movsb \n\
|
||
|
|
movsb \n\
|
||
|
|
0: \n\
|
||
|
|
# All done! \n\
|
||
|
|
emms # Clean up after MMX instructions \n\
|
||
|
|
sfence # Flush the write buffer \n\
|
||
|
|
pop %%rdi # Restore destination (return value) \n\
|
||
|
|
" : /* no outputs */
|
||
|
|
: "D" (dest), "S" (src), "c" (bytes)
|
||
|
|
: "%rax", "%rbx", "%rdx"
|
||
|
|
);
|
||
|
|
return dest;
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* HAVE_ASM_SSE2 && ARCH_X86_64 */
|
||
|
|
|
||
|
|
/*************************************************************************/
|
||
|
|
|
||
|
|
/* Initialization routine. */
|
||
|
|
|
||
|
|
int ac_memcpy_init(int accel)
|
||
|
|
{
|
||
|
|
memcpy_ptr = memmove;
|
||
|
|
|
||
|
|
#if defined(HAVE_ASM_MMX) && defined(ARCH_X86)
|
||
|
|
if (HAS_ACCEL(accel, AC_MMX))
|
||
|
|
memcpy_ptr = memcpy_mmx;
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#if defined(HAVE_ASM_SSE) && defined(ARCH_X86)
|
||
|
|
if (HAS_ACCEL(accel, AC_CMOVE|AC_SSE))
|
||
|
|
memcpy_ptr = memcpy_sse;
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#if defined(HAVE_ASM_SSE2) && defined(ARCH_X86_64)
|
||
|
|
if (HAS_ACCEL(accel, AC_CMOVE|AC_SSE2))
|
||
|
|
memcpy_ptr = memcpy_amd64;
|
||
|
|
#endif
|
||
|
|
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*************************************************************************/
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Local variables:
|
||
|
|
* c-file-style: "stroustrup"
|
||
|
|
* c-file-offsets: ((case-label . *) (statement-case-intro . *))
|
||
|
|
* indent-tabs-mode: nil
|
||
|
|
* End:
|
||
|
|
*
|
||
|
|
* vim: expandtab shiftwidth=4:
|
||
|
|
*/
|