diff options
Diffstat (limited to 'lib/libc/mips/string/bcmp.S')
| -rw-r--r-- | lib/libc/mips/string/bcmp.S | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/lib/libc/mips/string/bcmp.S b/lib/libc/mips/string/bcmp.S new file mode 100644 index 0000000..ffcaeeb --- /dev/null +++ b/lib/libc/mips/string/bcmp.S @@ -0,0 +1,130 @@ +/* $NetBSD: bcmp.S,v 1.9 2009/12/14 01:07:42 matt Exp $ */ + +/*- + * Copyright (c) 1991, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Ralph Campbell. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <machine/asm.h> +__FBSDID("$FreeBSD$"); + +#define _LOCORE /* XXX not really, just assembly-code source */ +#include <machine/endian.h> /* LWLO/LWHI, SWLO/SWHI */ + +#if defined(LIBC_SCCS) && !defined(lint) +#if 0 + ASMSTR("from: @(#)bcmp.s 8.1 (Berkeley) 6/4/93") +#else + ASMSTR("$NetBSD: bcmp.S,v 1.9 2009/12/14 01:07:42 matt Exp $") +#endif +#endif /* LIBC_SCCS and not lint */ + +#ifdef __ABICALLS__ + .abicalls +#endif + +/* bcmp(s1, s2, n) */ + + +LEAF(bcmp) + .set noreorder + blt a2, 16, small # is it worth any trouble? + xor v0, a0, a1 # compare low two bits of addresses + and v0, v0, 3 + PTR_SUBU a3, zero, a1 # compute # bytes to word align address + bne v0, zero, unaligned # not possible to align addresses + and a3, a3, 3 + + beq a3, zero, 1f + PTR_SUBU a2, a2, a3 # subtract from remaining count + move v0, v1 # init v0,v1 so unmodified bytes match + LWHI v0, 0(a0) # read 1, 2, or 3 bytes + LWHI v1, 0(a1) + PTR_ADDU a1, a1, a3 + bne v0, v1, nomatch + PTR_ADDU a0, a0, a3 +1: + and a3, a2, ~3 # compute number of whole words left + PTR_SUBU a2, a2, a3 # which has to be >= (16-3) & ~3 + PTR_ADDU a3, a3, a0 # compute ending address +2: + lw v0, 0(a0) # compare words + lw v1, 0(a1) + PTR_ADDU a0, a0, 4 + bne v0, v1, nomatch + PTR_ADDU a1, a1, 4 + bne a0, a3, 2b + nop + b small # finish remainder + nop +unaligned: + beq a3, zero, 2f + PTR_SUBU a2, a2, a3 # subtract from remaining count + PTR_ADDU a3, a3, a0 # compute ending address +1: + lbu v0, 0(a0) # compare bytes until a1 word aligned + lbu v1, 0(a1) + PTR_ADDU a0, a0, 1 + bne v0, v1, nomatch + PTR_ADDU a1, a1, 1 + bne a0, a3, 1b + nop +2: + and a3, a2, ~3 # compute number of whole words left + PTR_SUBU a2, a2, a3 # which has to be >= (16-3) & ~3 + PTR_ADDU a3, a3, a0 # compute ending address +3: + LWHI v0, 0(a0) # compare words a0 unaligned, a1 aligned + LWLO v0, 3(a0) + lw v1, 0(a1) + PTR_ADDU a0, a0, 4 + bne v0, v1, nomatch + PTR_ADDU a1, a1, 4 + bne a0, a3, 3b + nop +small: + ble a2, zero, match + PTR_ADDU a3, a2, a0 # compute ending address +1: + lbu v0, 0(a0) + lbu v1, 0(a1) + PTR_ADDU a0, a0, 1 + bne v0, v1, nomatch + PTR_ADDU a1, a1, 1 + bne a0, a3, 1b + nop +match: + j ra + move v0, zero +nomatch: + j ra + li v0, 1 + .set reorder +END(bcmp) |
