/* * Copyright (c) 2006 Apple Computer, Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ #include #include /* * The bcopy/memcpy loops for very long operands, tuned for 64-bit * Pentium-M class processors with SSE4 and 64-byte cache lines. * This is the 64-bit version. * * The following #defines are tightly coupled to the u-architecture: */ #define kBigChunk (256*1024) // outer loop chunk size for kVeryLong sized operands // Very long forward moves. These are at least several pages, so we loop over big // chunks of memory (kBigChunk in size.) We first prefetch the chunk, and then copy // it using non-temporal stores. Hopefully all the reads occur in the prefetch loop, // so the copy loop reads from L2 and writes directly to memory (with write combining.) // This minimizes bus turnaround and maintains good DRAM page locality. // Note that for this scheme to work, kVeryLong must be a large fraction of L2 cache // size. Otherwise, it is counter-productive to bypass L2 on the stores. // // We are called from the commpage bcopy loops when they encounter very long // operands, with the standard ABI: // rdi = dest ptr // rsi = source ptr // rdx = length (>= 8kb, probably much bigger) .text .code64 .align 5, 0x90 Llongcopy_sse4_64: // void longcopy(const void *dest, void *sou, size_t len) pushq %rbp // set up a frame for backtraces movq %rsp,%rbp movl %edi,%eax // copy dest ptr negl %eax andl $63,%eax // get #bytes to cache line align destination jz LBigChunkLoop // already aligned // Cache line align destination, so temporal stores in copy loops work right. // The recursive call returns with the source and dest ptrs properly updated. subq %rax,%rdx // get length remaining after dest is aligned pushq %rdx // save length remaining movl %eax,%edx // #bytes to copy to align destination movq $_COMM_PAGE_32_TO_64(_COMM_PAGE_MEMCPY),%rax call *%rax popq %rdx // recover adjusted length // Loop over big chunks. // rdx = length remaining (>= 4096) // rdi = dest (64-byte aligned) // rsi = source (may be unaligned) LBigChunkLoop: movl $(kBigChunk),%r8d // assume we can do a full chunk cmpq %r8,%rdx // do we have a full chunk left to do? cmovbl %edx,%r8d // if not, only move what we have left andl $-4096,%r8d // we work in page multiples xorl %eax,%eax // initialize chunk offset jmp LTouchLoop // Touch in the next chunk. We try to keep the prefetch unit in "kick-start" mode, // by touching two adjacent cache lines every 8 lines of each page, in four slices. // Because the source may be unaligned, we use byte loads to touch. // rdx = length remaining (including this chunk) // rdi = ptr to start of dest chunk // rsi = ptr to start of source chunk // r8d = chunk length (multiples of pages, less than 2**32) // ecx = scratch reg used to read a byte of each cache line // eax = chunk offset .align 4,0x90 // 16-byte align inner loops LTouchLoop: movzb (%rsi,%rax),%ecx // touch line 0, 2, 4, or 6 of page movzb 1*64(%rsi,%rax),%ecx // touch line 1, 3, 5, or 7 movzb 8*64(%rsi,%rax),%ecx // touch line 8, 10, 12, or 14 movzb 9*64(%rsi,%rax),%ecx // etc movzb 16*64(%rsi,%rax),%ecx movzb 17*64(%rsi,%rax),%ecx movzb 24*64(%rsi,%rax),%ecx movzb 25*64(%rsi,%rax),%ecx movzb 32*64(%rsi,%rax),%ecx movzb 33*64(%rsi,%rax),%ecx movzb 40*64(%rsi,%rax),%ecx movzb 41*64(%rsi,%rax),%ecx movzb 48*64(%rsi,%rax),%ecx movzb 49*64(%rsi,%rax),%ecx movzb 56*64(%rsi,%rax),%ecx movzb 57*64(%rsi,%rax),%ecx subl $-128,%eax // next slice of page (adding 128 w 8-bit immediate) testl $512,%eax // done with this page? jz LTouchLoop // no, next of four slices addl $(4096-512),%eax // move on to next page cmpl %eax,%r8d // done with this chunk? jnz LTouchLoop // no, do next page // The chunk has been pre-fetched, now copy it using non-temporal stores. // There are two copy loops, depending on whether the source is 16-byte aligned // or not. movl %r8d,%ecx // copy chunk size to a reg that doesn't use REX prefix addq %rcx,%rsi // increment ptrs by chunk length addq %rcx,%rdi subq %rcx,%rdx // adjust remaining length negq %rcx // prepare loop index (counts up to 0) testl $15,%esi // is source 16-byte aligned? jnz LVeryLongUnaligned // no jmp LVeryLongAligned .align 4,0x90 // 16-byte align inner loops LVeryLongAligned: // aligned loop over 128-bytes movdqa (%rsi,%rcx),%xmm0 movdqa 16(%rsi,%rcx),%xmm1 movdqa 32(%rsi,%rcx),%xmm2 movdqa 48(%rsi,%rcx),%xmm3 movdqa 64(%rsi,%rcx),%xmm4 movdqa 80(%rsi,%rcx),%xmm5 movdqa 96(%rsi,%rcx),%xmm6 movdqa 112(%rsi,%rcx),%xmm7 movntdq %xmm0,(%rdi,%rcx) movntdq %xmm1,16(%rdi,%rcx) movntdq %xmm2,32(%rdi,%rcx) movntdq %xmm3,48(%rdi,%rcx) movntdq %xmm4,64(%rdi,%rcx) movntdq %xmm5,80(%rdi,%rcx) movntdq %xmm6,96(%rdi,%rcx) movntdq %xmm7,112(%rdi,%rcx) subq $-128,%rcx // add 128 with an 8-bit immediate jnz LVeryLongAligned jmp LVeryLongChunkEnd .align 4,0x90 // 16-byte align inner loops LVeryLongUnaligned: // unaligned loop over 128-bytes movdqu (%rsi,%rcx),%xmm0 movdqu 16(%rsi,%rcx),%xmm1 movdqu 32(%rsi,%rcx),%xmm2 movdqu 48(%rsi,%rcx),%xmm3 movdqu 64(%rsi,%rcx),%xmm4 movdqu 80(%rsi,%rcx),%xmm5 movdqu 96(%rsi,%rcx),%xmm6 movdqu 112(%rsi,%rcx),%xmm7 movntdq %xmm0,(%rdi,%rcx) movntdq %xmm1,16(%rdi,%rcx) movntdq %xmm2,32(%rdi,%rcx) movntdq %xmm3,48(%rdi,%rcx) movntdq %xmm4,64(%rdi,%rcx) movntdq %xmm5,80(%rdi,%rcx) movntdq %xmm6,96(%rdi,%rcx) movntdq %xmm7,112(%rdi,%rcx) subq $-128,%rcx // add 128 with an 8-bit immediate jnz LVeryLongUnaligned LVeryLongChunkEnd: cmpq $4096,%rdx // at least another page to go? jae LBigChunkLoop // yes // Done. Call memcpy() again to handle the 0-4095 bytes at the end. // We still have the args in the right registers: // rdi = destination ptr // rsi = source ptr // rdx = length remaining (0..4095) sfence // required by non-temporal stores testl %edx,%edx // anything left to copy? jz 1f movq $_COMM_PAGE_32_TO_64(_COMM_PAGE_MEMCPY),%rax call *%rax 1: popq %rbp // restore frame ptr ret /* always match for now, as commpage_stuff_routine() will panic if no match */ COMMPAGE_DESCRIPTOR(longcopy_sse4_64, _COMM_PAGE_LONGCOPY, 0 ,0)