bcmp.S revision 1.7
1 1.7 thorpej /* $NetBSD: bcmp.S,v 1.7 2002/11/10 18:10:25 thorpej 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 1.6 jonathan #define _LOCORE /* XXX not really, just assembly-code source */ 41 1.6 jonathan #include <machine/endian.h> /* LWLO/LWHI, SWLO/SWHI */ 42 1.1 glass 43 1.1 glass #if defined(LIBC_SCCS) && !defined(lint) 44 1.1 glass ASMSTR("from: @(#)bcmp.s 8.1 (Berkeley) 6/4/93") 45 1.7 thorpej ASMSTR("$NetBSD: bcmp.S,v 1.7 2002/11/10 18:10:25 thorpej Exp $") 46 1.1 glass #endif /* LIBC_SCCS and not lint */ 47 1.5 jonathan 48 1.7 thorpej #ifdef __ABICALLS__ 49 1.5 jonathan .abicalls 50 1.5 jonathan #endif 51 1.1 glass 52 1.1 glass /* bcmp(s1, s2, n) */ 53 1.1 glass 54 1.1 glass 55 1.3 mycroft LEAF(bcmp) 56 1.1 glass .set noreorder 57 1.1 glass blt a2, 16, small # is it worth any trouble? 58 1.1 glass xor v0, a0, a1 # compare low two bits of addresses 59 1.1 glass and v0, v0, 3 60 1.1 glass subu a3, zero, a1 # compute # bytes to word align address 61 1.1 glass bne v0, zero, unaligned # not possible to align addresses 62 1.1 glass and a3, a3, 3 63 1.1 glass 64 1.1 glass beq a3, zero, 1f 65 1.1 glass subu a2, a2, a3 # subtract from remaining count 66 1.1 glass move v0, v1 # init v0,v1 so unmodified bytes match 67 1.1 glass LWHI v0, 0(a0) # read 1, 2, or 3 bytes 68 1.1 glass LWHI v1, 0(a1) 69 1.1 glass addu a1, a1, a3 70 1.1 glass bne v0, v1, nomatch 71 1.1 glass addu a0, a0, a3 72 1.1 glass 1: 73 1.1 glass and a3, a2, ~3 # compute number of whole words left 74 1.1 glass subu a2, a2, a3 # which has to be >= (16-3) & ~3 75 1.1 glass addu a3, a3, a0 # compute ending address 76 1.1 glass 2: 77 1.1 glass lw v0, 0(a0) # compare words 78 1.1 glass lw v1, 0(a1) 79 1.1 glass addu a0, a0, 4 80 1.1 glass bne v0, v1, nomatch 81 1.1 glass addu a1, a1, 4 82 1.1 glass bne a0, a3, 2b 83 1.1 glass nop 84 1.1 glass b small # finish remainder 85 1.1 glass nop 86 1.1 glass unaligned: 87 1.1 glass beq a3, zero, 2f 88 1.1 glass subu a2, a2, a3 # subtract from remaining count 89 1.1 glass addu a3, a3, a0 # compute ending address 90 1.1 glass 1: 91 1.1 glass lbu v0, 0(a0) # compare bytes until a1 word aligned 92 1.1 glass lbu v1, 0(a1) 93 1.1 glass addu a0, a0, 1 94 1.1 glass bne v0, v1, nomatch 95 1.1 glass addu a1, a1, 1 96 1.1 glass bne a0, a3, 1b 97 1.1 glass nop 98 1.1 glass 2: 99 1.1 glass and a3, a2, ~3 # compute number of whole words left 100 1.1 glass subu a2, a2, a3 # which has to be >= (16-3) & ~3 101 1.1 glass addu a3, a3, a0 # compute ending address 102 1.1 glass 3: 103 1.1 glass LWHI v0, 0(a0) # compare words a0 unaligned, a1 aligned 104 1.1 glass LWLO v0, 3(a0) 105 1.1 glass lw v1, 0(a1) 106 1.1 glass addu a0, a0, 4 107 1.1 glass bne v0, v1, nomatch 108 1.1 glass addu a1, a1, 4 109 1.1 glass bne a0, a3, 3b 110 1.1 glass nop 111 1.1 glass small: 112 1.1 glass ble a2, zero, match 113 1.1 glass addu a3, a2, a0 # compute ending address 114 1.1 glass 1: 115 1.1 glass lbu v0, 0(a0) 116 1.1 glass lbu v1, 0(a1) 117 1.1 glass addu a0, a0, 1 118 1.1 glass bne v0, v1, nomatch 119 1.1 glass addu a1, a1, 1 120 1.1 glass bne a0, a3, 1b 121 1.1 glass nop 122 1.1 glass match: 123 1.1 glass j ra 124 1.1 glass move v0, zero 125 1.1 glass nomatch: 126 1.1 glass j ra 127 1.1 glass li v0, 1 128 1.1 glass .set reorder 129 1.3 mycroft END(bcmp) 130
Indexes created Tue Sep 23 02:09:52 GMT 2025