bcmp.S revision 1.3
1 1.1 glass /*- 2 1.1 glass * Copyright (c) 1991, 1993 3 1.1 glass * The Regents of the University of California. All rights reserved. 4 1.1 glass * 5 1.1 glass * This code is derived from software contributed to Berkeley by 6 1.1 glass * Ralph Campbell. 7 1.1 glass * 8 1.1 glass * Redistribution and use in source and binary forms, with or without 9 1.1 glass * modification, are permitted provided that the following conditions 10 1.1 glass * are met: 11 1.1 glass * 1. Redistributions of source code must retain the above copyright 12 1.1 glass * notice, this list of conditions and the following disclaimer. 13 1.1 glass * 2. Redistributions in binary form must reproduce the above copyright 14 1.1 glass * notice, this list of conditions and the following disclaimer in the 15 1.1 glass * documentation and/or other materials provided with the distribution. 16 1.1 glass * 3. All advertising materials mentioning features or use of this software 17 1.1 glass * must display the following acknowledgement: 18 1.1 glass * This product includes software developed by the University of 19 1.1 glass * California, Berkeley and its contributors. 20 1.1 glass * 4. Neither the name of the University nor the names of its contributors 21 1.1 glass * may be used to endorse or promote products derived from this software 22 1.1 glass * without specific prior written permission. 23 1.1 glass * 24 1.1 glass * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 1.1 glass * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 1.1 glass * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 1.1 glass * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 1.1 glass * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 1.1 glass * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 1.1 glass * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 1.1 glass * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 1.1 glass * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 1.1 glass * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 1.1 glass * SUCH DAMAGE. 35 1.1 glass */ 36 1.1 glass 37 1.1 glass #include <machine/machAsmDefs.h> 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 1.3 mycroft ASMSTR("$Id: bcmp.S,v 1.3 1994/12/15 17:24:57 mycroft Exp $") 42 1.1 glass #endif /* LIBC_SCCS and not lint */ 43 1.1 glass 44 1.1 glass /* bcmp(s1, s2, n) */ 45 1.1 glass 46 1.1 glass #ifdef MIPSEL 47 1.1 glass # define LWHI lwr 48 1.1 glass # define LWLO lwl 49 1.1 glass # define SWHI swr 50 1.1 glass # define SWLO swl 51 1.1 glass #endif 52 1.1 glass #ifdef MIPSEB 53 1.1 glass # define LWHI lwl 54 1.1 glass # define LWLO lwr 55 1.1 glass # define SWHI swl 56 1.1 glass # define SWLO swr 57 1.1 glass #endif 58 1.1 glass 59 1.3 mycroft LEAF(bcmp) 60 1.1 glass .set noreorder 61 1.1 glass blt a2, 16, small # is it worth any trouble? 62 1.1 glass xor v0, a0, a1 # compare low two bits of addresses 63 1.1 glass and v0, v0, 3 64 1.1 glass subu a3, zero, a1 # compute # bytes to word align address 65 1.1 glass bne v0, zero, unaligned # not possible to align addresses 66 1.1 glass and a3, a3, 3 67 1.1 glass 68 1.1 glass beq a3, zero, 1f 69 1.1 glass subu a2, a2, a3 # subtract from remaining count 70 1.1 glass move v0, v1 # init v0,v1 so unmodified bytes match 71 1.1 glass LWHI v0, 0(a0) # read 1, 2, or 3 bytes 72 1.1 glass LWHI v1, 0(a1) 73 1.1 glass addu a1, a1, a3 74 1.1 glass bne v0, v1, nomatch 75 1.1 glass addu a0, a0, a3 76 1.1 glass 1: 77 1.1 glass and a3, a2, ~3 # compute number of whole words left 78 1.1 glass subu a2, a2, a3 # which has to be >= (16-3) & ~3 79 1.1 glass addu a3, a3, a0 # compute ending address 80 1.1 glass 2: 81 1.1 glass lw v0, 0(a0) # compare words 82 1.1 glass lw v1, 0(a1) 83 1.1 glass addu a0, a0, 4 84 1.1 glass bne v0, v1, nomatch 85 1.1 glass addu a1, a1, 4 86 1.1 glass bne a0, a3, 2b 87 1.1 glass nop 88 1.1 glass b small # finish remainder 89 1.1 glass nop 90 1.1 glass unaligned: 91 1.1 glass beq a3, zero, 2f 92 1.1 glass subu a2, a2, a3 # subtract from remaining count 93 1.1 glass addu a3, a3, a0 # compute ending address 94 1.1 glass 1: 95 1.1 glass lbu v0, 0(a0) # compare bytes until a1 word aligned 96 1.1 glass lbu v1, 0(a1) 97 1.1 glass addu a0, a0, 1 98 1.1 glass bne v0, v1, nomatch 99 1.1 glass addu a1, a1, 1 100 1.1 glass bne a0, a3, 1b 101 1.1 glass nop 102 1.1 glass 2: 103 1.1 glass and a3, a2, ~3 # compute number of whole words left 104 1.1 glass subu a2, a2, a3 # which has to be >= (16-3) & ~3 105 1.1 glass addu a3, a3, a0 # compute ending address 106 1.1 glass 3: 107 1.1 glass LWHI v0, 0(a0) # compare words a0 unaligned, a1 aligned 108 1.1 glass LWLO v0, 3(a0) 109 1.1 glass lw v1, 0(a1) 110 1.1 glass addu a0, a0, 4 111 1.1 glass bne v0, v1, nomatch 112 1.1 glass addu a1, a1, 4 113 1.1 glass bne a0, a3, 3b 114 1.1 glass nop 115 1.1 glass small: 116 1.1 glass ble a2, zero, match 117 1.1 glass addu a3, a2, a0 # compute ending address 118 1.1 glass 1: 119 1.1 glass lbu v0, 0(a0) 120 1.1 glass lbu v1, 0(a1) 121 1.1 glass addu a0, a0, 1 122 1.1 glass bne v0, v1, nomatch 123 1.1 glass addu a1, a1, 1 124 1.1 glass bne a0, a3, 1b 125 1.1 glass nop 126 1.1 glass match: 127 1.1 glass j ra 128 1.1 glass move v0, zero 129 1.1 glass nomatch: 130 1.1 glass j ra 131 1.1 glass li v0, 1 132 1.1 glass .set reorder 133 1.3 mycroft END(bcmp) 134
Indexes created Mon Sep 22 21:09:42 GMT 2025