bcmp.S revision 1.5
1 1.5 jonathan /* $NetBSD: bcmp.S,v 1.5 1996/09/17 01:32:30 jonathan Exp $ */ 2 1.4 jonathan 3 1.1 glass /*- 4 1.1 glass * Copyright (c) 1991, 1993 5 1.1 glass * The Regents of the University of California. All rights reserved. 6 1.1 glass * 7 1.1 glass * This code is derived from software contributed to Berkeley by 8 1.1 glass * Ralph Campbell. 9 1.1 glass * 10 1.1 glass * Redistribution and use in source and binary forms, with or without 11 1.1 glass * modification, are permitted provided that the following conditions 12 1.1 glass * are met: 13 1.1 glass * 1. Redistributions of source code must retain the above copyright 14 1.1 glass * notice, this list of conditions and the following disclaimer. 15 1.1 glass * 2. Redistributions in binary form must reproduce the above copyright 16 1.1 glass * notice, this list of conditions and the following disclaimer in the 17 1.1 glass * documentation and/or other materials provided with the distribution. 18 1.1 glass * 3. All advertising materials mentioning features or use of this software 19 1.1 glass * must display the following acknowledgement: 20 1.1 glass * This product includes software developed by the University of 21 1.1 glass * California, Berkeley and its contributors. 22 1.1 glass * 4. Neither the name of the University nor the names of its contributors 23 1.1 glass * may be used to endorse or promote products derived from this software 24 1.1 glass * without specific prior written permission. 25 1.1 glass * 26 1.1 glass * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 1.1 glass * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 1.1 glass * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 1.1 glass * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 1.1 glass * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 1.1 glass * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 1.1 glass * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 1.1 glass * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 1.1 glass * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 1.1 glass * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 1.1 glass * SUCH DAMAGE. 37 1.1 glass */ 38 1.1 glass 39 1.5 jonathan #include <mips/asm.h> 40 1.1 glass 41 1.1 glass #if defined(LIBC_SCCS) && !defined(lint) 42 1.1 glass ASMSTR("from: @(#)bcmp.s 8.1 (Berkeley) 6/4/93") 43 1.5 jonathan ASMSTR("$NetBSD: bcmp.S,v 1.5 1996/09/17 01:32:30 jonathan Exp $") 44 1.1 glass #endif /* LIBC_SCCS and not lint */ 45 1.5 jonathan 46 1.5 jonathan #ifdef ABICALLS 47 1.5 jonathan .abicalls 48 1.5 jonathan #endif 49 1.1 glass 50 1.1 glass /* bcmp(s1, s2, n) */ 51 1.1 glass 52 1.1 glass #ifdef MIPSEL 53 1.1 glass # define LWHI lwr 54 1.1 glass # define LWLO lwl 55 1.1 glass # define SWHI swr 56 1.1 glass # define SWLO swl 57 1.1 glass #endif 58 1.1 glass #ifdef MIPSEB 59 1.1 glass # define LWHI lwl 60 1.1 glass # define LWLO lwr 61 1.1 glass # define SWHI swl 62 1.1 glass # define SWLO swr 63 1.1 glass #endif 64 1.1 glass 65 1.3 mycroft LEAF(bcmp) 66 1.1 glass .set noreorder 67 1.1 glass blt a2, 16, small # is it worth any trouble? 68 1.1 glass xor v0, a0, a1 # compare low two bits of addresses 69 1.1 glass and v0, v0, 3 70 1.1 glass subu a3, zero, a1 # compute # bytes to word align address 71 1.1 glass bne v0, zero, unaligned # not possible to align addresses 72 1.1 glass and a3, a3, 3 73 1.1 glass 74 1.1 glass beq a3, zero, 1f 75 1.1 glass subu a2, a2, a3 # subtract from remaining count 76 1.1 glass move v0, v1 # init v0,v1 so unmodified bytes match 77 1.1 glass LWHI v0, 0(a0) # read 1, 2, or 3 bytes 78 1.1 glass LWHI v1, 0(a1) 79 1.1 glass addu a1, a1, a3 80 1.1 glass bne v0, v1, nomatch 81 1.1 glass addu a0, a0, a3 82 1.1 glass 1: 83 1.1 glass and a3, a2, ~3 # compute number of whole words left 84 1.1 glass subu a2, a2, a3 # which has to be >= (16-3) & ~3 85 1.1 glass addu a3, a3, a0 # compute ending address 86 1.1 glass 2: 87 1.1 glass lw v0, 0(a0) # compare words 88 1.1 glass lw v1, 0(a1) 89 1.1 glass addu a0, a0, 4 90 1.1 glass bne v0, v1, nomatch 91 1.1 glass addu a1, a1, 4 92 1.1 glass bne a0, a3, 2b 93 1.1 glass nop 94 1.1 glass b small # finish remainder 95 1.1 glass nop 96 1.1 glass unaligned: 97 1.1 glass beq a3, zero, 2f 98 1.1 glass subu a2, a2, a3 # subtract from remaining count 99 1.1 glass addu a3, a3, a0 # compute ending address 100 1.1 glass 1: 101 1.1 glass lbu v0, 0(a0) # compare bytes until a1 word aligned 102 1.1 glass lbu v1, 0(a1) 103 1.1 glass addu a0, a0, 1 104 1.1 glass bne v0, v1, nomatch 105 1.1 glass addu a1, a1, 1 106 1.1 glass bne a0, a3, 1b 107 1.1 glass nop 108 1.1 glass 2: 109 1.1 glass and a3, a2, ~3 # compute number of whole words left 110 1.1 glass subu a2, a2, a3 # which has to be >= (16-3) & ~3 111 1.1 glass addu a3, a3, a0 # compute ending address 112 1.1 glass 3: 113 1.1 glass LWHI v0, 0(a0) # compare words a0 unaligned, a1 aligned 114 1.1 glass LWLO v0, 3(a0) 115 1.1 glass lw v1, 0(a1) 116 1.1 glass addu a0, a0, 4 117 1.1 glass bne v0, v1, nomatch 118 1.1 glass addu a1, a1, 4 119 1.1 glass bne a0, a3, 3b 120 1.1 glass nop 121 1.1 glass small: 122 1.1 glass ble a2, zero, match 123 1.1 glass addu a3, a2, a0 # compute ending address 124 1.1 glass 1: 125 1.1 glass lbu v0, 0(a0) 126 1.1 glass lbu v1, 0(a1) 127 1.1 glass addu a0, a0, 1 128 1.1 glass bne v0, v1, nomatch 129 1.1 glass addu a1, a1, 1 130 1.1 glass bne a0, a3, 1b 131 1.1 glass nop 132 1.1 glass match: 133 1.1 glass j ra 134 1.1 glass move v0, zero 135 1.1 glass nomatch: 136 1.1 glass j ra 137 1.1 glass li v0, 1 138 1.1 glass .set reorder 139 1.3 mycroft END(bcmp) 140
Indexes created Wed Sep 24 22:09:59 GMT 2025