/* $NetBSD: memcmp.S,v 1.6 2025/12/31 15:33:50 andvar Exp $ */ /*- * Copyright (c) 1990 The Regents of the University of California. * All rights reserved. * * This code is derived from software contributed to Berkeley by * the Systems Programming Group of the University of Utah Computer * Science Department. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. 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. * 3. Neither the name of the University 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 REGENTS 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 REGENTS 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. */ #include <machine/asm.h> #if defined(LIBC_SCCS) && !defined(lint) #if 0 RCSID("from: @(#)bcmp.s 5.1 (Berkeley) 5/12/90") #else RCSID("$NetBSD: memcmp.S,v 1.6 2025/12/31 15:33:50 andvar Exp $") #endif #endif /* LIBC_SCCS and not lint */ /* memcmp(s1, s2, n) */ #ifdef __mcoldfire__ #define CMPMB(a,b) movb b,%d2; cmpb a,%d2 #define CMPMW(a,b) movw b,%d2; cmpw a,%d2 #define CMPML(a,b) movl b,%d2; cmpl a,%d2 #else #define CMPMB(a,b) cmpmb a,b #define CMPMW(a,b) cmpmw a,b #define CMPML(a,b) cmpml a,b #endif /* * This is probably not the best we can do, but it is still 2-10 times * faster than the C version in the portable gen directory. * * Things that might help: * - longword align when possible (only on the 68020) * - use nested DBcc instructions or use one and limit size to 64K */ ENTRY(memcmp) movl 4(%sp),%a0 | string 1 movl 8(%sp),%a1 | string 2 movl 12(%sp),%d0 | length #ifdef __mcoldfire__ movl %d2,-(%sp) | save temp #endif jeq .Lbcdone | if zero, nothing to do movl %a0,%d1 btst #0,%d1 | string 1 address odd? jeq .Lbceven | no, skip alignment CMPMB((%a0)+,(%a1)+) | yes, compare a byte jne .Lbcnoteq | not equal, return non-zero subql #1,%d0 | adjust count jeq .Lbcdone | count 0, return zero .Lbceven: movl %a1,%d1 btst #0,%d1 | string 2 address odd? jne .Lbcbloop | yes, no hope for alignment, compare bytes movl %d0,%d1 | no, both even lsrl #2,%d1 | convert count to longword count jeq .Lbcbloop | count 0, skip longword loop .Lbclloop: CMPML((%a0)+,(%a1)+) | compare a longword jne .Lbcnoteql | not equal, return non-zero subql #1,%d1 | adjust count jne .Lbclloop | still more, keep comparing andl #3,%d0 | what remains jeq .Lbcdone | nothing, all done .Lbcbloop: CMPMB((%a0)+,(%a1)+) | compare a byte jne .Lbcnoteq | not equal, return non-zero subql #1,%d0 | adjust count jne .Lbcbloop | still more, keep going rts .Lbcnoteql: subql #4,%a0 subql #4,%a1 movl #4,%d0 jra .Lbcbloop .Lbcnoteq: clrl %d0 clrl %d1 movb -(%a0),%d0 movb -(%a1),%d1 subl %d1,%d0 .Lbcdone: #ifdef __mcoldfire__ movl (%sp)+,%sp | restore temp #endif rts END(memcmp)
