/* * Copyright (C) 1991, 1992 Free Software Foundation, Inc. * This file is part of the GNU C Library. * * The GNU C Library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public License as * published by the Free Software Foundation; either version 2 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 * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with the GNU C Library; see the file COPYING.LIB in the * root directory of this distribution. If not, write to the, 1992 * Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #define op_t unsigned long int #define OPSIZ (sizeof(op_t)) /* Type to use for unaligned operations. */ typedef unsigned char byte; /* 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) \ { \ 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); extern void _wordcopy_fwd_dest_aligned (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) /* 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); extern void _wordcopy_bwd_dest_aligned (long int, long int, size_t); #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) /* Threshold value for when to enter the unrolled loops. */ #define OP_T_THRES 16 #if defined(__mc68020__) || defined(mc68020) #undef OP_T_THRES #define OP_T_THRES 16 /* WORD_COPY_FWD and WORD_COPY_BWD are not symmetric on the 68020, because of its weird instruction overlap characteristics. */ #undef WORD_COPY_FWD #define WORD_COPY_FWD(dst_bp, src_bp, nbytes_left, nbytes) \ do \ { \ size_t __nwords = (nbytes) / sizeof (op_t); \ size_t __nblocks = __nwords / 8 + 1; \ dst_bp -= (8 - __nwords % 8) * sizeof (op_t); \ src_bp -= (8 - __nwords % 8) * sizeof (op_t); \ switch (__nwords % 8) \ do \ { \ ((op_t *) dst_bp)[0] = ((op_t *) src_bp)[0]; \ case 7: \ ((op_t *) dst_bp)[1] = ((op_t *) src_bp)[1]; \ case 6: \ ((op_t *) dst_bp)[2] = ((op_t *) src_bp)[2]; \ case 5: \ ((op_t *) dst_bp)[3] = ((op_t *) src_bp)[3]; \ case 4: \ ((op_t *) dst_bp)[4] = ((op_t *) src_bp)[4]; \ case 3: \ ((op_t *) dst_bp)[5] = ((op_t *) src_bp)[5]; \ case 2: \ ((op_t *) dst_bp)[6] = ((op_t *) src_bp)[6]; \ case 1: \ ((op_t *) dst_bp)[7] = ((op_t *) src_bp)[7]; \ case 0: \ src_bp += 32; \ dst_bp += 32; \ __nblocks--; \ } \ while (__nblocks != 0); \ (nbytes_left) = (nbytes) % sizeof (op_t); \ } while (0) #undef WORD_COPY_BWD #define WORD_COPY_BWD(dst_ep, src_ep, nbytes_left, nbytes) \ do \ { \ size_t __nblocks = (nbytes) / 32 + 1; \ switch ((nbytes) / sizeof (op_t) % 8) \ do \ { \ *--((op_t *) dst_ep) = *--((op_t *) src_ep); \ case 7: \ *--((op_t *) dst_ep) = *--((op_t *) src_ep); \ case 6: \ *--((op_t *) dst_ep) = *--((op_t *) src_ep); \ case 5: \ *--((op_t *) dst_ep) = *--((op_t *) src_ep); \ case 4: \ *--((op_t *) dst_ep) = *--((op_t *) src_ep); \ case 3: \ *--((op_t *) dst_ep) = *--((op_t *) src_ep); \ case 2: \ *--((op_t *) dst_ep) = *--((op_t *) src_ep); \ case 1: \ *--((op_t *) dst_ep) = *--((op_t *) src_ep); \ case 0: \ __nblocks--; \ } \ while (__nblocks != 0); \ (nbytes_left) = (nbytes) % sizeof (op_t); \ } while (0) #endif void * bcopy(const void * from, void * to, size_t len) { unsigned long int dstp = (long int) to; unsigned long int srcp = (long int) from; /* 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 from SRCP to DSTP taking advantage of the known alignment of DSTP. Number of bytes remaining is put in the third argumnet, 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 to; }