memccpy.S revision 1.2
11.2Smatt/* $NetBSD: memccpy.S,v 1.2 2013/07/16 20:49:42 matt Exp $ */ 21.1Sscottr 31.1Sscottr/* 41.1Sscottr * Copyright (C) 1999 Scott Reynolds. All rights reserved. 51.1Sscottr * 61.1Sscottr * Redistribution and use in source and binary forms, with or without 71.1Sscottr * modification, are permitted provided that the following conditions 81.1Sscottr * are met: 91.1Sscottr * 1. Redistributions of source code must retain the above copyright 101.1Sscottr * notice, this list of conditions and the following disclaimer. 111.1Sscottr * 2. Redistributions in binary form must reproduce the above copyright 121.1Sscottr * notice, this list of conditions and the following disclaimer in the 131.1Sscottr * documentation and/or other materials provided with the distribution. 141.1Sscottr * 3. The name of the author may not be used to endorse or promote products 151.1Sscottr * derived from this software without specific prior written permission. 161.1Sscottr * 171.1Sscottr * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 181.1Sscottr * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 191.1Sscottr * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 201.1Sscottr * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 211.1Sscottr * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 221.1Sscottr * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 231.1Sscottr * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 241.1Sscottr * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 251.1Sscottr * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 261.1Sscottr * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 271.1Sscottr */ 281.1Sscottr 291.1Sscottr#include <machine/asm.h> 301.1Sscottr 311.1Sscottr#if defined(LIBC_SCCS) && !defined(lint) 321.2Smatt RCSID("$NetBSD: memccpy.S,v 1.2 2013/07/16 20:49:42 matt Exp $") 331.1Sscottr#endif /* LIBC_SCCS and not lint */ 341.1Sscottr 351.1SscottrENTRY(memccpy) 361.2Smatt movl 16(%sp),%d0 | count 371.1Sscottr jeq Lmcbail | nothing to do 381.1Sscottr 391.2Smatt movl 4(%sp),%a0 | a0 = toaddr 401.1Sscottr subql #1,%d0 | prepare count for DBcc loop 411.2Smatt movl 8(%sp),%a1 | a1 = fromaddr 421.2Smatt movl 12(%sp),%d1 | d1 = terminator 431.1Sscottr jeq Lmcloop | handle ASCII NUL specially 441.1Sscottr 451.2Smatt movl %d2,-(%sp) | save scratch register 461.1SscottrLmcnzloop: 471.2Smatt movb (%a1)+,%d2 | move a byte 481.2Smatt movb %d2,(%a0)+ 491.1Sscottr cmpb %d2,%d1 | found the terminator? 501.1Sscottr dbeq %d0,Lmcnzloop | if not, keep transferring, 511.1Sscottr jeq Lmcnzdone | otherwise done 521.1Sscottr clrw %d0 | check to see if more to do 531.1Sscottr subql #1,%d0 541.1Sscottr jcc Lmcnzloop | yes, keep going... 551.1Sscottr 561.2Smatt movl (%sp)+,%d2 | restore scratch register 571.1Sscottr movql #0,%d0 | no terminator found, return NULL 581.1Sscottr#ifdef __SVR4_ABI__ 591.1Sscottr movl %d0,%a0 | XXX maybe use lea to avoid stall? 601.1Sscottr#endif 611.1Sscottr rts 621.1Sscottr 631.1SscottrLmcloop: 641.2Smatt movb (%a1)+,(%a0)+ | move a byte; was it NUL? 651.1Sscottr dbeq %d0,Lmcloop | if not, keep transferring, 661.1Sscottr jeq Lmcdone | otherwise done 671.1Sscottr clrw %d0 | check to see if more to do 681.1Sscottr subql #1,%d0 691.1Sscottr jcc Lmcloop | yes, keep going... 701.1Sscottr | Note: %d0 is now -1! 711.1Sscottr movql #0,%d0 | no terminator found, return NULL 721.1SscottrLmcbail: 731.1Sscottr#ifdef __SVR4_ABI__ 741.1Sscottr movl %d0,%a0 | XXX maybe use lea to avoid stall? 751.1Sscottr#endif 761.1Sscottr rts 771.1Sscottr 781.1SscottrLmcnzdone: 791.2Smatt movl (%sp)+,%d2 | restore scratch register 801.1SscottrLmcdone: 811.1Sscottr movl %a0,%d0 821.1Sscottr rts 83