minix/lib/libc/arch/mips/string/bcmp.S
Ben Gras 2fe8fb192f Full switch to clang/ELF. Drop ack. Simplify.
There is important information about booting non-ack images in
docs/UPDATING. ack/aout-format images can't be built any more, and
booting clang/ELF-format ones is a little different. Updating to the
new boot monitor is recommended.

Changes in this commit:

	. drop boot monitor -> allowing dropping ack support
	. facility to copy ELF boot files to /boot so that old boot monitor
	  can still boot fairly easily, see UPDATING
	. no more ack-format libraries -> single-case libraries
	. some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases
	. drop several ack toolchain commands, but not all support
	  commands (e.g. aal is gone but acksize is not yet).
	. a few libc files moved to netbsd libc dir
	. new /bin/date as minix date used code in libc/
	. test compile fix
	. harmonize includes
	. /usr/lib is no longer special: without ack, /usr/lib plays no
	  kind of special bootstrapping role any more and bootstrapping
	  is done exclusively through packages, so releases depend even
	  less on the state of the machine making them now.
	. rename nbsd_lib* to lib*
	. reduce mtree
2012-02-14 14:52:02 +01:00

124 lines
3.8 KiB
ArmAsm

/* $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 <mips/asm.h>
#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
RCSID("from: @(#)bcmp.s 8.1 (Berkeley) 6/4/93")
#else
RCSID("$NetBSD: bcmp.S,v 1.9 2009/12/14 01:07:42 matt Exp $")
#endif
#endif /* LIBC_SCCS and not lint */
/* 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)