Return to bcopy.c CVS log

Up to [local] / sys / arch / powerpc / powerpc

Annotation of sys/arch/powerpc/powerpc/bcopy.c, Revision 1.1.1.1

1.1       nbrk        1: /*     $OpenBSD: bcopy.c,v 1.5 2003/10/15 02:43:09 drahn Exp $ */
                      2: /*-
                      3:  * Copyright (c) 1990 The Regents of the University of California.
                      4:  * All rights reserved.
                      5:  *
                      6:  * This code is derived from software contributed to Berkeley by
                      7:  * Chris Torek.
                      8:  *
                      9:  * Redistribution and use in source and binary forms, with or without
                     10:  * modification, are permitted provided that the following conditions
                     11:  * are met:
                     12:  * 1. Redistributions of source code must retain the above copyright
                     13:  *    notice, this list of conditions and the following disclaimer.
                     14:  * 2. Redistributions in binary form must reproduce the above copyright
                     15:  *    notice, this list of conditions and the following disclaimer in the
                     16:  *    documentation and/or other materials provided with the distribution.
                     17:  * 3. Neither the name of the University nor the names of its contributors
                     18:  *    may be used to endorse or promote products derived from this software
                     19:  *    without specific prior written permission.
                     20:  *
                     21:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     22:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     23:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     24:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     25:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     26:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     27:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     28:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     29:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     30:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     31:  * SUCH DAMAGE.
                     32:  */
                     33:
                     34: #if defined(LIBC_SCCS) && !defined(lint)
                     35: /*static char *sccsid = "from: @(#)bcopy.c     5.11 (Berkeley) 6/21/91";*/
                     36: static char *rcsid = "$Id: bcopy.c,v 1.5 2003/10/15 02:43:09 drahn Exp $";
                     37: #endif /* LIBC_SCCS and not lint */
                     38:
                     39: #include <sys/cdefs.h>
                     40: /*
                     41: #include <string.h>
                     42: */
                     43: #include <sys/types.h>
                     44: #include <sys/systm.h>
                     45:
                     46: /*
                     47:  * sizeof(word) MUST BE A POWER OF TWO
                     48:  * SO THAT wmask BELOW IS ALL ONES
                     49:  */
                     50: typedef        int word;               /* "word" used for optimal copy speed */
                     51:
                     52: #define        wsize   sizeof(word)
                     53: #define        wmask   (wsize - 1)
                     54:
                     55: /*
                     56:  * Copy a block of memory, handling overlap.
                     57:  * This is the routine that actually implements
                     58:  * (the portable versions of) bcopy, memcpy, and memmove.
                     59:  */
                     60: #ifdef MEMCOPY
                     61: void *
                     62: memcpy(void *dst0, const void *src0, size_t length)
                     63: #else
                     64: #ifdef MEMMOVE
                     65: void *
                     66: memmove(void *dst0, const void *src0, size_t length)
                     67: #else
                     68: void
                     69: bcopy(const void *src0, void *dst0, size_t length)
                     70: #endif
                     71: #endif
                     72: {
                     73:        char *dst = dst0;
                     74:        const char *src = src0;
                     75:        size_t t;
                     76:
                     77:        if (length == 0 || dst == src)          /* nothing to do */
                     78:                goto done;
                     79:
                     80:        /*
                     81:         * Macros: loop-t-times; and loop-t-times, t>0
                     82:         */
                     83: #define        TLOOP(s) if (t) TLOOP1(s)
                     84: #define        TLOOP1(s) do { s; } while (--t)
                     85:
                     86:        if ((unsigned long)dst < (unsigned long)src) {
                     87:                /*
                     88:                 * Copy forward.
                     89:                 */
                     90:                t = (int)src;   /* only need low bits */
                     91:                if ((t | (int)dst) & wmask) {
                     92:                        /*
                     93:                         * Try to align operands.  This cannot be done
                     94:                         * unless the low bits match.
                     95:                         */
                     96:                        if ((t ^ (int)dst) & wmask || length < wsize)
                     97:                                t = length;
                     98:                        else
                     99:                                t = wsize - (t & wmask);
                    100:                        length -= t;
                    101:                        TLOOP1(*dst++ = *src++);
                    102:                }
                    103:                /*
                    104:                 * Copy whole words, then mop up any trailing bytes.
                    105:                 */
                    106:                t = length / wsize;
                    107:                TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize);
                    108:                t = length & wmask;
                    109:                TLOOP(*dst++ = *src++);
                    110:        } else {
                    111:                /*
                    112:                 * Copy backwards.  Otherwise essentially the same.
                    113:                 * Alignment works as before, except that it takes
                    114:                 * (t&wmask) bytes to align, not wsize-(t&wmask).
                    115:                 */
                    116:                src += length;
                    117:                dst += length;
                    118:                t = (int)src;
                    119:                if ((t | (int)dst) & wmask) {
                    120:                        if ((t ^ (int)dst) & wmask || length <= wsize)
                    121:                                t = length;
                    122:                        else
                    123:                                t &= wmask;
                    124:                        length -= t;
                    125:                        TLOOP1(*--dst = *--src);
                    126:                }
                    127:                t = length / wsize;
                    128:                TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src);
                    129:                t = length & wmask;
                    130:                TLOOP(*--dst = *--src);
                    131:        }
                    132: done:
                    133: #if defined(MEMCOPY) || defined(MEMMOVE)
                    134:        return (dst0);
                    135: #else
                    136:        return;
                    137: #endif
                    138: }