1209231Sjchandra/* $NetBSD: bcmp.S,v 1.9 2009/12/14 01:07:42 matt Exp $ */ 2178580Simp 3178580Simp/*- 4178580Simp * Copyright (c) 1991, 1993 5178580Simp * The Regents of the University of California. All rights reserved. 6178580Simp * 7178580Simp * This code is derived from software contributed to Berkeley by 8178580Simp * Ralph Campbell. 9178580Simp * 10178580Simp * Redistribution and use in source and binary forms, with or without 11178580Simp * modification, are permitted provided that the following conditions 12178580Simp * are met: 13178580Simp * 1. Redistributions of source code must retain the above copyright 14178580Simp * notice, this list of conditions and the following disclaimer. 15178580Simp * 2. Redistributions in binary form must reproduce the above copyright 16178580Simp * notice, this list of conditions and the following disclaimer in the 17178580Simp * documentation and/or other materials provided with the distribution. 18178580Simp * 3. Neither the name of the University nor the names of its contributors 19178580Simp * may be used to endorse or promote products derived from this software 20178580Simp * without specific prior written permission. 21178580Simp * 22178580Simp * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23178580Simp * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24178580Simp * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25178580Simp * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26178580Simp * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27178580Simp * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28178580Simp * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29178580Simp * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30178580Simp * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31178580Simp * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32178580Simp * SUCH DAMAGE. 33178580Simp */ 34178580Simp 35178580Simp#include <machine/asm.h> 36178580Simp__FBSDID("$FreeBSD$"); 37178580Simp 38209231Sjchandra#define _LOCORE /* XXX not really, just assembly-code source */ 39209231Sjchandra#include <machine/endian.h> /* LWLO/LWHI, SWLO/SWHI */ 40209231Sjchandra 41178580Simp#if defined(LIBC_SCCS) && !defined(lint) 42209231Sjchandra#if 0 43178580Simp ASMSTR("from: @(#)bcmp.s 8.1 (Berkeley) 6/4/93") 44209231Sjchandra#else 45209231Sjchandra ASMSTR("$NetBSD: bcmp.S,v 1.9 2009/12/14 01:07:42 matt Exp $") 46209231Sjchandra#endif 47178580Simp#endif /* LIBC_SCCS and not lint */ 48178580Simp 49178580Simp#ifdef __ABICALLS__ 50178580Simp .abicalls 51178580Simp#endif 52178580Simp 53178580Simp/* bcmp(s1, s2, n) */ 54178580Simp 55178580Simp 56178580SimpLEAF(bcmp) 57178580Simp .set noreorder 58209231Sjchandra blt a2, 16, small # is it worth any trouble? 59209231Sjchandra xor v0, a0, a1 # compare low two bits of addresses 60209231Sjchandra and v0, v0, 3 61209231Sjchandra PTR_SUBU a3, zero, a1 # compute # bytes to word align address 62209231Sjchandra bne v0, zero, unaligned # not possible to align addresses 63209231Sjchandra and a3, a3, 3 64178580Simp 65209231Sjchandra beq a3, zero, 1f 66209231Sjchandra PTR_SUBU a2, a2, a3 # subtract from remaining count 67209231Sjchandra move v0, v1 # init v0,v1 so unmodified bytes match 68209231Sjchandra LWHI v0, 0(a0) # read 1, 2, or 3 bytes 69209231Sjchandra LWHI v1, 0(a1) 70209231Sjchandra PTR_ADDU a1, a1, a3 71209231Sjchandra bne v0, v1, nomatch 72209231Sjchandra PTR_ADDU a0, a0, a3 73178580Simp1: 74209231Sjchandra and a3, a2, ~3 # compute number of whole words left 75209231Sjchandra PTR_SUBU a2, a2, a3 # which has to be >= (16-3) & ~3 76209231Sjchandra PTR_ADDU a3, a3, a0 # compute ending address 77178580Simp2: 78209231Sjchandra lw v0, 0(a0) # compare words 79209231Sjchandra lw v1, 0(a1) 80209231Sjchandra PTR_ADDU a0, a0, 4 81209231Sjchandra bne v0, v1, nomatch 82209231Sjchandra PTR_ADDU a1, a1, 4 83209231Sjchandra bne a0, a3, 2b 84178580Simp nop 85209231Sjchandra b small # finish remainder 86178580Simp nop 87178580Simpunaligned: 88209231Sjchandra beq a3, zero, 2f 89209231Sjchandra PTR_SUBU a2, a2, a3 # subtract from remaining count 90209231Sjchandra PTR_ADDU a3, a3, a0 # compute ending address 91178580Simp1: 92209231Sjchandra lbu v0, 0(a0) # compare bytes until a1 word aligned 93209231Sjchandra lbu v1, 0(a1) 94209231Sjchandra PTR_ADDU a0, a0, 1 95209231Sjchandra bne v0, v1, nomatch 96209231Sjchandra PTR_ADDU a1, a1, 1 97209231Sjchandra bne a0, a3, 1b 98178580Simp nop 99178580Simp2: 100209231Sjchandra and a3, a2, ~3 # compute number of whole words left 101209231Sjchandra PTR_SUBU a2, a2, a3 # which has to be >= (16-3) & ~3 102209231Sjchandra PTR_ADDU a3, a3, a0 # compute ending address 103178580Simp3: 104209231Sjchandra LWHI v0, 0(a0) # compare words a0 unaligned, a1 aligned 105209231Sjchandra LWLO v0, 3(a0) 106209231Sjchandra lw v1, 0(a1) 107209231Sjchandra PTR_ADDU a0, a0, 4 108209231Sjchandra bne v0, v1, nomatch 109209231Sjchandra PTR_ADDU a1, a1, 4 110209231Sjchandra bne a0, a3, 3b 111178580Simp nop 112178580Simpsmall: 113209231Sjchandra ble a2, zero, match 114209231Sjchandra PTR_ADDU a3, a2, a0 # compute ending address 115178580Simp1: 116209231Sjchandra lbu v0, 0(a0) 117209231Sjchandra lbu v1, 0(a1) 118209231Sjchandra PTR_ADDU a0, a0, 1 119209231Sjchandra bne v0, v1, nomatch 120209231Sjchandra PTR_ADDU a1, a1, 1 121209231Sjchandra bne a0, a3, 1b 122178580Simp nop 123178580Simpmatch: 124209231Sjchandra j ra 125209231Sjchandra move v0, zero 126178580Simpnomatch: 127209231Sjchandra j ra 128209231Sjchandra li v0, 1 129178580Simp .set reorder 130178580SimpEND(bcmp) 131