/* $NetBSD: memmove.S,v 1.3 2011/01/15 07:31:12 matt Exp $ */ /* stropt/memmove.S, pl_string_common, pl_linux 10/11/04 11:45:37 * ========================================================================== * Optimized memmove implementation for IBM PowerPC 405/440. * * Copyright (c) 2003, IBM Corporation * All rights reserved. * * Redistribution and use in source and binary forms, with or * without modification, are permitted provided that the following * conditions are met: * * * Redistributions of source code must retain the above * copyright notice, this list of conditions and the following * disclaimer. * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following * disclaimer in the documentation and/or other materials * provided with the distribution. * * Neither the name of IBM nor the names of its contributors * may be used to endorse or promote products derived from this * software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * ========================================================================== * * Function: Move memory area (handles overlapping regions) * * void *memmove(void * dest, const void * src, int n) * * Input: r3 - destination address * r4 - source address * r5 - byte count * Output: r3 - destination address * * ========================================================================== */ #include <machine/asm.h> .text .align 4 #ifdef _BCOPY /* bcopy = memcpy/memmove with arguments reversed. */ /* LINTSTUB: Func: void bcopy(void *, void *, size_t) */ ENTRY(bcopy) mr %r6, %r3 /* swap src/dst */ mr %r3, %r4 mr %r4, %r6 #else /* LINTSTUB: Func: void *memmove(void *, const void *, size_t) */ ENTRY(memmove) #endif mr %r8, %r3 /* Save dst (return value) */ cmpw %r4, %r8 /* Branch to reverse if */ blt reverse /* src < dest. Don't want to */ /* overwrite end of src with */ /* start of dest */ addi %r4, %r4, -4 /* Back up src and dst pointers */ addi %r8, %r8, -4 /* due to auto-update of 'load' */ srwi. %r9,%r5,2 /* How many words in total cnt */ beq- last1 /* Handle byte by byte if < 4 */ /* bytes total */ mtctr %r9 /* Count of words for loop */ lwzu %r7, 4(%r4) /* Preload first word */ b g1 g0: /* Main loop */ lwzu %r7, 4(%r4) /* Load a new word */ stwu %r6, 4(%r8) /* Store previous word */ g1: bdz- last /* Dec cnt, and branch if just */ /* one word to store */ lwzu %r6, 4(%r4) /* Load another word */ stwu %r7, 4(%r8) /* Store previous word */ bdnz+ g0 /* Dec cnt, and loop again if */ /* more words */ mr %r7, %r6 /* If word count -> 0, then... */ last: stwu %r7, 4(%r8) /* ... store last word */ last1: /* Byte-by-byte copy */ clrlwi. %r5,%r5,30 /* If count -> 0, then ... */ beqlr /* we're done */ mtctr %r5 /* else load count for loop */ lbzu %r6, 4(%r4) /* 1st byte: update addr by 4 */ stbu %r6, 4(%r8) /* since we pre-adjusted by 4 */ bdzlr- /* in anticipation of main loop */ last2: lbzu %r6, 1(%r4) /* But handle the rest by */ stbu %r6, 1(%r8) /* updating addr by 1 */ bdnz+ last2 blr /* We're here since src < dest. Don't want to overwrite end of */ /* src with start of dest */ reverse: add %r4, %r4, %r5 /* Work from end to beginning */ add %r8, %r8, %r5 /* so add count to string ptrs */ srwi. %r9,%r5,2 /* Words in total count */ beq- rlast1 /* Handle byte by byte if < 4 */ /* bytes total */ mtctr %r9 /* Count of words for loop */ lwzu %r7, -4(%r4) /* Preload first word */ b rg1 rg0: /* Main loop */ lwzu %r7, -4(%r4) /* Load a new word */ stwu %r6, -4(%r8) /* Store previous word */ rg1: bdz- rlast /* Dec cnt, and branch if just */ /* one word to store */ lwzu %r6, -4(%r4) /* Load another word */ stwu %r7, -4(%r8) /* Store previous word */ bdnz+ rg0 /* Dec cnt, and loop again if */ /* more words */ mr %r7, %r6 /* If word count -> 0, then... */ rlast: stwu %r7, -4(%r8) /* ... store last word */ rlast1: /* Byte-by-byte copy */ clrlwi. %r5,%r5,30 /* If count -> 0, then... */ beqlr /* ... we're done */ mtctr %r5 /* else load count for loop */ rlast2: lbzu %r6, -1(%r4) /* Handle the rest, byte by */ stbu %r6, -1(%r8) /* byte */ bdnz+ rlast2 /* Dec ctr, and branch if more */ /* bytes left */ blr #ifdef _BCOPY END(bcopy) #else END(memmove) #endif
