bcmp.S revision 1.9
1 1.9 matt /* $NetBSD: bcmp.S,v 1.9 2009/12/14 01:07:42 matt 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 1.9 matt #if 0 41 1.9 matt RCSID("from: @(#)bcmp.s 8.1 (Berkeley) 6/4/93") 42 1.9 matt #else 43 1.9 matt RCSID("$NetBSD: bcmp.S,v 1.9 2009/12/14 01:07:42 matt Exp $") 44 1.9 matt #endif 45 1.1 glass #endif /* LIBC_SCCS and not lint */ 46 1.5 jonathan 47 1.1 glass /* bcmp(s1, s2, n) */ 48 1.1 glass 49 1.1 glass 50 1.3 mycroft LEAF(bcmp) 51 1.1 glass .set noreorder 52 1.9 matt blt a2, 16, small # is it worth any trouble? 53 1.9 matt xor v0, a0, a1 # compare low two bits of addresses 54 1.9 matt and v0, v0, 3 55 1.9 matt PTR_SUBU a3, zero, a1 # compute # bytes to word align address 56 1.9 matt bne v0, zero, unaligned # not possible to align addresses 57 1.9 matt and a3, a3, 3 58 1.9 matt 59 1.9 matt beq a3, zero, 1f 60 1.9 matt PTR_SUBU a2, a2, a3 # subtract from remaining count 61 1.9 matt move v0, v1 # init v0,v1 so unmodified bytes match 62 1.9 matt LWHI v0, 0(a0) # read 1, 2, or 3 bytes 63 1.9 matt LWHI v1, 0(a1) 64 1.9 matt PTR_ADDU a1, a1, a3 65 1.9 matt bne v0, v1, nomatch 66 1.9 matt PTR_ADDU a0, a0, a3 67 1.1 glass 1: 68 1.9 matt and a3, a2, ~3 # compute number of whole words left 69 1.9 matt PTR_SUBU a2, a2, a3 # which has to be >= (16-3) & ~3 70 1.9 matt PTR_ADDU a3, a3, a0 # compute ending address 71 1.1 glass 2: 72 1.9 matt lw v0, 0(a0) # compare words 73 1.9 matt lw v1, 0(a1) 74 1.9 matt PTR_ADDU a0, a0, 4 75 1.9 matt bne v0, v1, nomatch 76 1.9 matt PTR_ADDU a1, a1, 4 77 1.9 matt bne a0, a3, 2b 78 1.1 glass nop 79 1.9 matt b small # finish remainder 80 1.1 glass nop 81 1.1 glass unaligned: 82 1.9 matt beq a3, zero, 2f 83 1.9 matt PTR_SUBU a2, a2, a3 # subtract from remaining count 84 1.9 matt PTR_ADDU a3, a3, a0 # compute ending address 85 1.1 glass 1: 86 1.9 matt lbu v0, 0(a0) # compare bytes until a1 word aligned 87 1.9 matt lbu v1, 0(a1) 88 1.9 matt PTR_ADDU a0, a0, 1 89 1.9 matt bne v0, v1, nomatch 90 1.9 matt PTR_ADDU a1, a1, 1 91 1.9 matt bne a0, a3, 1b 92 1.1 glass nop 93 1.1 glass 2: 94 1.9 matt and a3, a2, ~3 # compute number of whole words left 95 1.9 matt PTR_SUBU a2, a2, a3 # which has to be >= (16-3) & ~3 96 1.9 matt PTR_ADDU a3, a3, a0 # compute ending address 97 1.1 glass 3: 98 1.9 matt LWHI v0, 0(a0) # compare words a0 unaligned, a1 aligned 99 1.9 matt LWLO v0, 3(a0) 100 1.9 matt lw v1, 0(a1) 101 1.9 matt PTR_ADDU a0, a0, 4 102 1.9 matt bne v0, v1, nomatch 103 1.9 matt PTR_ADDU a1, a1, 4 104 1.9 matt bne a0, a3, 3b 105 1.1 glass nop 106 1.1 glass small: 107 1.9 matt ble a2, zero, match 108 1.9 matt PTR_ADDU a3, a2, a0 # compute ending address 109 1.1 glass 1: 110 1.9 matt lbu v0, 0(a0) 111 1.9 matt lbu v1, 0(a1) 112 1.9 matt PTR_ADDU a0, a0, 1 113 1.9 matt bne v0, v1, nomatch 114 1.9 matt PTR_ADDU a1, a1, 1 115 1.9 matt bne a0, a3, 1b 116 1.1 glass nop 117 1.1 glass match: 118 1.9 matt j ra 119 1.9 matt move v0, zero 120 1.1 glass nomatch: 121 1.9 matt j ra 122 1.9 matt li v0, 1 123 1.1 glass .set reorder 124 1.3 mycroft END(bcmp) 125
Indexes created Thu Sep 25 06:09:39 GMT 2025