bcmp.S revision 1.4
1 1.4 jonathan /* $NetBSD: bcmp.S,v 1.4 1996/09/16 18:11:17 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 1.1 glass #include <machine/machAsmDefs.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 1.4 jonathan ASMSTR("$NetBSD: bcmp.S,v 1.4 1996/09/16 18:11:17 jonathan Exp $") 44 1.1 glass #endif /* LIBC_SCCS and not lint */ 45 1.1 glass 46 1.1 glass /* bcmp(s1, s2, n) */ 47 1.1 glass 48 1.1 glass #ifdef MIPSEL 49 1.1 glass # define LWHI lwr 50 1.1 glass # define LWLO lwl 51 1.1 glass # define SWHI swr 52 1.1 glass # define SWLO swl 53 1.1 glass #endif 54 1.1 glass #ifdef MIPSEB 55 1.1 glass # define LWHI lwl 56 1.1 glass # define LWLO lwr 57 1.1 glass # define SWHI swl 58 1.1 glass # define SWLO swr 59 1.1 glass #endif 60 1.1 glass 61 1.3 mycroft LEAF(bcmp) 62 1.1 glass .set noreorder 63 1.1 glass blt a2, 16, small # is it worth any trouble? 64 1.1 glass xor v0, a0, a1 # compare low two bits of addresses 65 1.1 glass and v0, v0, 3 66 1.1 glass subu a3, zero, a1 # compute # bytes to word align address 67 1.1 glass bne v0, zero, unaligned # not possible to align addresses 68 1.1 glass and a3, a3, 3 69 1.1 glass 70 1.1 glass beq a3, zero, 1f 71 1.1 glass subu a2, a2, a3 # subtract from remaining count 72 1.1 glass move v0, v1 # init v0,v1 so unmodified bytes match 73 1.1 glass LWHI v0, 0(a0) # read 1, 2, or 3 bytes 74 1.1 glass LWHI v1, 0(a1) 75 1.1 glass addu a1, a1, a3 76 1.1 glass bne v0, v1, nomatch 77 1.1 glass addu a0, a0, a3 78 1.1 glass 1: 79 1.1 glass and a3, a2, ~3 # compute number of whole words left 80 1.1 glass subu a2, a2, a3 # which has to be >= (16-3) & ~3 81 1.1 glass addu a3, a3, a0 # compute ending address 82 1.1 glass 2: 83 1.1 glass lw v0, 0(a0) # compare words 84 1.1 glass lw v1, 0(a1) 85 1.1 glass addu a0, a0, 4 86 1.1 glass bne v0, v1, nomatch 87 1.1 glass addu a1, a1, 4 88 1.1 glass bne a0, a3, 2b 89 1.1 glass nop 90 1.1 glass b small # finish remainder 91 1.1 glass nop 92 1.1 glass unaligned: 93 1.1 glass beq a3, zero, 2f 94 1.1 glass subu a2, a2, a3 # subtract from remaining count 95 1.1 glass addu a3, a3, a0 # compute ending address 96 1.1 glass 1: 97 1.1 glass lbu v0, 0(a0) # compare bytes until a1 word aligned 98 1.1 glass lbu v1, 0(a1) 99 1.1 glass addu a0, a0, 1 100 1.1 glass bne v0, v1, nomatch 101 1.1 glass addu a1, a1, 1 102 1.1 glass bne a0, a3, 1b 103 1.1 glass nop 104 1.1 glass 2: 105 1.1 glass and a3, a2, ~3 # compute number of whole words left 106 1.1 glass subu a2, a2, a3 # which has to be >= (16-3) & ~3 107 1.1 glass addu a3, a3, a0 # compute ending address 108 1.1 glass 3: 109 1.1 glass LWHI v0, 0(a0) # compare words a0 unaligned, a1 aligned 110 1.1 glass LWLO v0, 3(a0) 111 1.1 glass lw v1, 0(a1) 112 1.1 glass addu a0, a0, 4 113 1.1 glass bne v0, v1, nomatch 114 1.1 glass addu a1, a1, 4 115 1.1 glass bne a0, a3, 3b 116 1.1 glass nop 117 1.1 glass small: 118 1.1 glass ble a2, zero, match 119 1.1 glass addu a3, a2, a0 # compute ending address 120 1.1 glass 1: 121 1.1 glass lbu v0, 0(a0) 122 1.1 glass lbu v1, 0(a1) 123 1.1 glass addu a0, a0, 1 124 1.1 glass bne v0, v1, nomatch 125 1.1 glass addu a1, a1, 1 126 1.1 glass bne a0, a3, 1b 127 1.1 glass nop 128 1.1 glass match: 129 1.1 glass j ra 130 1.1 glass move v0, zero 131 1.1 glass nomatch: 132 1.1 glass j ra 133 1.1 glass li v0, 1 134 1.1 glass .set reorder 135 1.3 mycroft END(bcmp) 136
Indexes created Tue Sep 23 22:09:46 GMT 2025