bcmp.S revision 1.8
1 1.8 agc /* $NetBSD: bcmp.S,v 1.8 2003/08/07 16:42:16 agc 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 1.8 agc * 3. Neither the name of the University nor the names of its contributors 19 1.1 glass * may be used to endorse or promote products derived from this software 20 1.1 glass * without specific prior written permission. 21 1.1 glass * 22 1.1 glass * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 1.1 glass * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 1.1 glass * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 1.1 glass * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 1.1 glass * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 1.1 glass * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 1.1 glass * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 1.1 glass * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 1.1 glass * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 1.1 glass * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 1.1 glass * SUCH DAMAGE. 33 1.1 glass */ 34 1.1 glass 35 1.5 jonathan #include <mips/asm.h> 36 1.6 jonathan #define _LOCORE /* XXX not really, just assembly-code source */ 37 1.6 jonathan #include <machine/endian.h> /* LWLO/LWHI, SWLO/SWHI */ 38 1.1 glass 39 1.1 glass #if defined(LIBC_SCCS) && !defined(lint) 40 1.1 glass ASMSTR("from: @(#)bcmp.s 8.1 (Berkeley) 6/4/93") 41 1.8 agc ASMSTR("$NetBSD: bcmp.S,v 1.8 2003/08/07 16:42:16 agc Exp $") 42 1.1 glass #endif /* LIBC_SCCS and not lint */ 43 1.5 jonathan 44 1.7 thorpej #ifdef __ABICALLS__ 45 1.5 jonathan .abicalls 46 1.5 jonathan #endif 47 1.1 glass 48 1.1 glass /* bcmp(s1, s2, n) */ 49 1.1 glass 50 1.1 glass 51 1.3 mycroft LEAF(bcmp) 52 1.1 glass .set noreorder 53 1.1 glass blt a2, 16, small # is it worth any trouble? 54 1.1 glass xor v0, a0, a1 # compare low two bits of addresses 55 1.1 glass and v0, v0, 3 56 1.1 glass subu a3, zero, a1 # compute # bytes to word align address 57 1.1 glass bne v0, zero, unaligned # not possible to align addresses 58 1.1 glass and a3, a3, 3 59 1.1 glass 60 1.1 glass beq a3, zero, 1f 61 1.1 glass subu a2, a2, a3 # subtract from remaining count 62 1.1 glass move v0, v1 # init v0,v1 so unmodified bytes match 63 1.1 glass LWHI v0, 0(a0) # read 1, 2, or 3 bytes 64 1.1 glass LWHI v1, 0(a1) 65 1.1 glass addu a1, a1, a3 66 1.1 glass bne v0, v1, nomatch 67 1.1 glass addu a0, a0, a3 68 1.1 glass 1: 69 1.1 glass and a3, a2, ~3 # compute number of whole words left 70 1.1 glass subu a2, a2, a3 # which has to be >= (16-3) & ~3 71 1.1 glass addu a3, a3, a0 # compute ending address 72 1.1 glass 2: 73 1.1 glass lw v0, 0(a0) # compare words 74 1.1 glass lw v1, 0(a1) 75 1.1 glass addu a0, a0, 4 76 1.1 glass bne v0, v1, nomatch 77 1.1 glass addu a1, a1, 4 78 1.1 glass bne a0, a3, 2b 79 1.1 glass nop 80 1.1 glass b small # finish remainder 81 1.1 glass nop 82 1.1 glass unaligned: 83 1.1 glass beq a3, zero, 2f 84 1.1 glass subu a2, a2, a3 # subtract from remaining count 85 1.1 glass addu a3, a3, a0 # compute ending address 86 1.1 glass 1: 87 1.1 glass lbu v0, 0(a0) # compare bytes until a1 word aligned 88 1.1 glass lbu v1, 0(a1) 89 1.1 glass addu a0, a0, 1 90 1.1 glass bne v0, v1, nomatch 91 1.1 glass addu a1, a1, 1 92 1.1 glass bne a0, a3, 1b 93 1.1 glass nop 94 1.1 glass 2: 95 1.1 glass and a3, a2, ~3 # compute number of whole words left 96 1.1 glass subu a2, a2, a3 # which has to be >= (16-3) & ~3 97 1.1 glass addu a3, a3, a0 # compute ending address 98 1.1 glass 3: 99 1.1 glass LWHI v0, 0(a0) # compare words a0 unaligned, a1 aligned 100 1.1 glass LWLO v0, 3(a0) 101 1.1 glass lw v1, 0(a1) 102 1.1 glass addu a0, a0, 4 103 1.1 glass bne v0, v1, nomatch 104 1.1 glass addu a1, a1, 4 105 1.1 glass bne a0, a3, 3b 106 1.1 glass nop 107 1.1 glass small: 108 1.1 glass ble a2, zero, match 109 1.1 glass addu a3, a2, a0 # compute ending address 110 1.1 glass 1: 111 1.1 glass lbu v0, 0(a0) 112 1.1 glass lbu v1, 0(a1) 113 1.1 glass addu a0, a0, 1 114 1.1 glass bne v0, v1, nomatch 115 1.1 glass addu a1, a1, 1 116 1.1 glass bne a0, a3, 1b 117 1.1 glass nop 118 1.1 glass match: 119 1.1 glass j ra 120 1.1 glass move v0, zero 121 1.1 glass nomatch: 122 1.1 glass j ra 123 1.1 glass li v0, 1 124 1.1 glass .set reorder 125 1.3 mycroft END(bcmp) 126
Indexes created Mon Sep 22 13:09:51 GMT 2025