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Diffstat (limited to 'sysdeps/generic/memcopy.h')
| -rw-r--r-- | sysdeps/generic/memcopy.h | 202 |
1 files changed, 0 insertions, 202 deletions
diff --git a/sysdeps/generic/memcopy.h b/sysdeps/generic/memcopy.h deleted file mode 100644 index 83b8fd6de8..0000000000 --- a/sysdeps/generic/memcopy.h +++ /dev/null @@ -1,202 +0,0 @@ -/* memcopy.h -- definitions for memory copy functions. Generic C version. - Copyright (C) 1991-2017 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contributed by Torbjorn Granlund (tege@sics.se). - - The GNU C 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 2.1 of the License, or (at your option) any later version. - - The GNU C 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 the GNU C Library; if not, see - <http://www.gnu.org/licenses/>. */ - -#ifndef _MEMCOPY_H -#define _MEMCOPY_H 1 - -/* The strategy of the memory functions is: - - 1. Copy bytes until the destination pointer is aligned. - - 2. Copy words in unrolled loops. If the source and destination - are not aligned in the same way, use word memory operations, - but shift and merge two read words before writing. - - 3. Copy the few remaining bytes. - - This is fast on processors that have at least 10 registers for - allocation by GCC, and that can access memory at reg+const in one - instruction. - - I made an "exhaustive" test of this memmove when I wrote it, - exhaustive in the sense that I tried all alignment and length - combinations, with and without overlap. */ - -#include <sys/cdefs.h> -#include <endian.h> -#include <pagecopy.h> - -/* The macros defined in this file are: - - BYTE_COPY_FWD(dst_beg_ptr, src_beg_ptr, nbytes_to_copy) - - BYTE_COPY_BWD(dst_end_ptr, src_end_ptr, nbytes_to_copy) - - WORD_COPY_FWD(dst_beg_ptr, src_beg_ptr, nbytes_remaining, nbytes_to_copy) - - WORD_COPY_BWD(dst_end_ptr, src_end_ptr, nbytes_remaining, nbytes_to_copy) - - MERGE(old_word, sh_1, new_word, sh_2) - [I fail to understand. I feel stupid. --roland] -*/ - -/* Type to use for aligned memory operations. - This should normally be the biggest type supported by a single load - and store. */ -#define op_t unsigned long int -#define OPSIZ (sizeof(op_t)) - -/* Type to use for unaligned operations. */ -typedef unsigned char byte; - -#if __BYTE_ORDER == __LITTLE_ENDIAN -#define MERGE(w0, sh_1, w1, sh_2) (((w0) >> (sh_1)) | ((w1) << (sh_2))) -#endif -#if __BYTE_ORDER == __BIG_ENDIAN -#define MERGE(w0, sh_1, w1, sh_2) (((w0) << (sh_1)) | ((w1) >> (sh_2))) -#endif - -/* Copy exactly NBYTES bytes from SRC_BP to DST_BP, - without any assumptions about alignment of the pointers. */ -#define BYTE_COPY_FWD(dst_bp, src_bp, nbytes) \ - do \ - { \ - size_t __nbytes = (nbytes); \ - while (__nbytes > 0) \ - { \ - byte __x = ((byte *) src_bp)[0]; \ - src_bp += 1; \ - __nbytes -= 1; \ - ((byte *) dst_bp)[0] = __x; \ - dst_bp += 1; \ - } \ - } while (0) - -/* Copy exactly NBYTES_TO_COPY bytes from SRC_END_PTR to DST_END_PTR, - beginning at the bytes right before the pointers and continuing towards - smaller addresses. Don't assume anything about alignment of the - pointers. */ -#define BYTE_COPY_BWD(dst_ep, src_ep, nbytes) \ - do \ - { \ - size_t __nbytes = (nbytes); \ - while (__nbytes > 0) \ - { \ - byte __x; \ - src_ep -= 1; \ - __x = ((byte *) src_ep)[0]; \ - dst_ep -= 1; \ - __nbytes -= 1; \ - ((byte *) dst_ep)[0] = __x; \ - } \ - } while (0) - -/* Copy *up to* NBYTES bytes from SRC_BP to DST_BP, with - the assumption that DST_BP is aligned on an OPSIZ multiple. If - not all bytes could be easily copied, store remaining number of bytes - in NBYTES_LEFT, otherwise store 0. */ -extern void _wordcopy_fwd_aligned (long int, long int, size_t) - attribute_hidden __THROW; -extern void _wordcopy_fwd_dest_aligned (long int, long int, size_t) - attribute_hidden __THROW; -#define WORD_COPY_FWD(dst_bp, src_bp, nbytes_left, nbytes) \ - do \ - { \ - if (src_bp % OPSIZ == 0) \ - _wordcopy_fwd_aligned (dst_bp, src_bp, (nbytes) / OPSIZ); \ - else \ - _wordcopy_fwd_dest_aligned (dst_bp, src_bp, (nbytes) / OPSIZ); \ - src_bp += (nbytes) & -OPSIZ; \ - dst_bp += (nbytes) & -OPSIZ; \ - (nbytes_left) = (nbytes) % OPSIZ; \ - } while (0) - -/* Copy *up to* NBYTES_TO_COPY bytes from SRC_END_PTR to DST_END_PTR, - beginning at the words (of type op_t) right before the pointers and - continuing towards smaller addresses. May take advantage of that - DST_END_PTR is aligned on an OPSIZ multiple. If not all bytes could be - easily copied, store remaining number of bytes in NBYTES_REMAINING, - otherwise store 0. */ -extern void _wordcopy_bwd_aligned (long int, long int, size_t) - attribute_hidden __THROW; -extern void _wordcopy_bwd_dest_aligned (long int, long int, size_t) - attribute_hidden __THROW; -#define WORD_COPY_BWD(dst_ep, src_ep, nbytes_left, nbytes) \ - do \ - { \ - if (src_ep % OPSIZ == 0) \ - _wordcopy_bwd_aligned (dst_ep, src_ep, (nbytes) / OPSIZ); \ - else \ - _wordcopy_bwd_dest_aligned (dst_ep, src_ep, (nbytes) / OPSIZ); \ - src_ep -= (nbytes) & -OPSIZ; \ - dst_ep -= (nbytes) & -OPSIZ; \ - (nbytes_left) = (nbytes) % OPSIZ; \ - } while (0) - -/* The macro PAGE_COPY_FWD_MAYBE (dstp, srcp, nbytes_left, nbytes) is invoked - like WORD_COPY_FWD et al. The pointers should be at least word aligned. - This will check if virtual copying by pages can and should be done and do it - if so. The pointers will be aligned to PAGE_SIZE bytes. The macro requires - that pagecopy.h defines at least PAGE_COPY_THRESHOLD to 0. If - PAGE_COPY_THRESHOLD is non-zero, the header must also define PAGE_COPY_FWD - and PAGE_SIZE. -*/ -#if PAGE_COPY_THRESHOLD - -# include <assert.h> - -# define PAGE_COPY_FWD_MAYBE(dstp, srcp, nbytes_left, nbytes) \ - do \ - { \ - if ((nbytes) >= PAGE_COPY_THRESHOLD && \ - PAGE_OFFSET ((dstp) - (srcp)) == 0) \ - { \ - /* The amount to copy is past the threshold for copying \ - pages virtually with kernel VM operations, and the \ - source and destination addresses have the same alignment. */ \ - size_t nbytes_before = PAGE_OFFSET (-(dstp)); \ - if (nbytes_before != 0) \ - { \ - /* First copy the words before the first page boundary. */ \ - WORD_COPY_FWD (dstp, srcp, nbytes_left, nbytes_before); \ - assert (nbytes_left == 0); \ - nbytes -= nbytes_before; \ - } \ - PAGE_COPY_FWD (dstp, srcp, nbytes_left, nbytes); \ - } \ - } while (0) - -/* The page size is always a power of two, so we can avoid modulo division. */ -# define PAGE_OFFSET(n) ((n) & (PAGE_SIZE - 1)) - -#else - -# define PAGE_COPY_FWD_MAYBE(dstp, srcp, nbytes_left, nbytes) /* nada */ - -#endif - -/* Threshold value for when to enter the unrolled loops. */ -#define OP_T_THRES 16 - -/* Set to 1 if memcpy is safe to use for forward-copying memmove with - overlapping addresses. This is 0 by default because memcpy implementations - are generally not safe for overlapping addresses. */ -#define MEMCPY_OK_FOR_FWD_MEMMOVE 0 - -#endif /* memcopy.h */ |