1/* $NetBSD: bzero.S,v 1.8 2003/08/07 16:42:16 agc Exp $ */
2
3/*-
4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Ralph Campbell.
9 *

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28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include <machine/asm.h>
36__FBSDID("$FreeBSD: head/lib/libc/mips/string/bzero.S 178580 2008-04-26 12:08:02Z imp $");
37
38#if defined(LIBC_SCCS) && !defined(lint)
39 ASMSTR("from: @(#)bzero.s 8.1 (Berkeley) 6/4/93")
40 ASMSTR("$NetBSD: bzero.S,v 1.8 2003/08/07 16:42:16 agc Exp $")
41#endif /* LIBC_SCCS and not lint */
42
43
44#ifdef __ABICALLS__
45 .abicalls
46#endif
47
48/* bzero(s1, n) */
49
50LEAF(bzero)
51 .set noreorder
52 blt a1, 12, smallclr # small amount to clear?
53 subu a3, zero, a0 # compute # bytes to word align address
54 and a3, a3, 3
55 beq a3, zero, 1f # skip if word aligned
56 subu a1, a1, a3 # subtract from remaining count
57#ifdef __MIPSEB__
58 swl zero, 0(a0) # clear 1, 2, or 3 bytes to align
59#else
60 swr zero, 0(a0) # clear 1, 2, or 3 bytes to align
61#endif
62 addu a0, a0, a3
631:
64 and v0, a1, 3 # compute number of words left
65 subu a3, a1, v0
66 move a1, v0
67 addu a3, a3, a0 # compute ending address
682:
69 addu a0, a0, 4 # clear words
70 bne a0, a3, 2b # unrolling loop doesnt help
71 sw zero, -4(a0) # since we are limited by memory speed
72smallclr:
73 ble a1, zero, 2f
74 addu a3, a1, a0 # compute ending address
751:
76 addu a0, a0, 1 # clear bytes
77 bne a0, a3, 1b
78 sb zero, -1(a0)
792:
80 j ra
81 nop
82END(bzero)