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Diffstat (limited to 'arch/nios2/lib/memcpy.c')
| -rw-r--r-- | arch/nios2/lib/memcpy.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/arch/nios2/lib/memcpy.c b/arch/nios2/lib/memcpy.c new file mode 100644 index 000000000..1715f5d28 --- /dev/null +++ b/arch/nios2/lib/memcpy.c @@ -0,0 +1,202 @@ +/* Extracted from GLIBC memcpy.c and memcopy.h, which is: + Copyright (C) 1991, 1992, 1993, 1997, 2004 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/>. */ + +#include <linux/types.h> + +/* 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)) + +/* Optimal type for storing bytes in registers. */ +#define reg_char char + +#define MERGE(w0, sh_1, w1, sh_2) (((w0) >> (sh_1)) | ((w1) << (sh_2))) + +/* 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) { \ + unsigned char __x = ((unsigned char *) src_bp)[0]; \ + src_bp += 1; \ + __nbytes -= 1; \ + ((unsigned char *) dst_bp)[0] = __x; \ + dst_bp += 1; \ + } \ +} 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 __P ((long int, long int, size_t)); */ +/* extern void _wordcopy_fwd_dest_aligned __P ((long int, long int, size_t)); */ +#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) + + +/* Threshold value for when to enter the unrolled loops. */ +#define OP_T_THRES 16 + +/* _wordcopy_fwd_aligned -- Copy block beginning at SRCP to + block beginning at DSTP with LEN `op_t' words (not LEN bytes!). + Both SRCP and DSTP should be aligned for memory operations on `op_t's. */ +/* stream-lined (read x8 + write x8) */ +static void _wordcopy_fwd_aligned(long int dstp, long int srcp, size_t len) +{ + while (len > 7) { + register op_t a0, a1, a2, a3, a4, a5, a6, a7; + + a0 = ((op_t *) srcp)[0]; + a1 = ((op_t *) srcp)[1]; + a2 = ((op_t *) srcp)[2]; + a3 = ((op_t *) srcp)[3]; + a4 = ((op_t *) srcp)[4]; + a5 = ((op_t *) srcp)[5]; + a6 = ((op_t *) srcp)[6]; + a7 = ((op_t *) srcp)[7]; + ((op_t *) dstp)[0] = a0; + ((op_t *) dstp)[1] = a1; + ((op_t *) dstp)[2] = a2; + ((op_t *) dstp)[3] = a3; + ((op_t *) dstp)[4] = a4; + ((op_t *) dstp)[5] = a5; + ((op_t *) dstp)[6] = a6; + ((op_t *) dstp)[7] = a7; + + srcp += 8 * OPSIZ; + dstp += 8 * OPSIZ; + len -= 8; + } + while (len > 0) { + *(op_t *)dstp = *(op_t *)srcp; + + srcp += OPSIZ; + dstp += OPSIZ; + len -= 1; + } +} + +/* _wordcopy_fwd_dest_aligned -- Copy block beginning at SRCP to + block beginning at DSTP with LEN `op_t' words (not LEN bytes!). + DSTP should be aligned for memory operations on `op_t's, but SRCP must + *not* be aligned. */ +/* stream-lined (read x4 + write x4) */ +static void _wordcopy_fwd_dest_aligned(long int dstp, long int srcp, + size_t len) +{ + op_t ap; + int sh_1, sh_2; + + /* Calculate how to shift a word read at the memory operation + aligned srcp to make it aligned for copy. */ + + sh_1 = 8 * (srcp % OPSIZ); + sh_2 = 8 * OPSIZ - sh_1; + + /* Make SRCP aligned by rounding it down to the beginning of the `op_t' + it points in the middle of. */ + srcp &= -OPSIZ; + ap = ((op_t *) srcp)[0]; + srcp += OPSIZ; + + while (len > 3) { + op_t a0, a1, a2, a3; + + a0 = ((op_t *) srcp)[0]; + a1 = ((op_t *) srcp)[1]; + a2 = ((op_t *) srcp)[2]; + a3 = ((op_t *) srcp)[3]; + ((op_t *) dstp)[0] = MERGE(ap, sh_1, a0, sh_2); + ((op_t *) dstp)[1] = MERGE(a0, sh_1, a1, sh_2); + ((op_t *) dstp)[2] = MERGE(a1, sh_1, a2, sh_2); + ((op_t *) dstp)[3] = MERGE(a2, sh_1, a3, sh_2); + + ap = a3; + srcp += 4 * OPSIZ; + dstp += 4 * OPSIZ; + len -= 4; + } + while (len > 0) { + register op_t a0; + + a0 = ((op_t *) srcp)[0]; + ((op_t *) dstp)[0] = MERGE(ap, sh_1, a0, sh_2); + + ap = a0; + srcp += OPSIZ; + dstp += OPSIZ; + len -= 1; + } +} + +void *memcpy(void *dstpp, const void *srcpp, size_t len) +{ + unsigned long int dstp = (long int) dstpp; + unsigned long int srcp = (long int) srcpp; + + /* Copy from the beginning to the end. */ + + /* If there not too few bytes to copy, use word copy. */ + if (len >= OP_T_THRES) { + /* Copy just a few bytes to make DSTP aligned. */ + len -= (-dstp) % OPSIZ; + BYTE_COPY_FWD(dstp, srcp, (-dstp) % OPSIZ); + + /* Copy whole pages from SRCP to DSTP by virtual address + manipulation, as much as possible. */ + + /* PAGE_COPY_FWD_MAYBE (dstp, srcp, len, len); */ + + /* Copy from SRCP to DSTP taking advantage of the known + alignment of DSTP. Number of bytes remaining is put in the + third argument, i.e. in LEN. This number may vary from + machine to machine. */ + + WORD_COPY_FWD(dstp, srcp, len, len); + + /* Fall out and copy the tail. */ + } + + /* There are just a few bytes to copy. Use byte memory operations. */ + BYTE_COPY_FWD(dstp, srcp, len); + + return dstpp; +} + +void *memcpyb(void *dstpp, const void *srcpp, unsigned len) +{ + unsigned long int dstp = (long int) dstpp; + unsigned long int srcp = (long int) srcpp; + + BYTE_COPY_FWD(dstp, srcp, len); + + return dstpp; +} |