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bzero.S revision 1.2 
      1 /*-
      2  * Copyright (c) 2006 The NetBSD Foundation, Inc.
      3  * All rights reserved.
      4  *
      5  * This code is derived from software contributed to The NetBSD Foundation
      6  * by Ross Harvey.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. All advertising materials mentioning features or use of this software
     17  *    must display the following acknowledgement:
     18  *        This product includes software developed by the NetBSD
     19  *        Foundation, Inc. and its contributors.
     20  * 4. Neither the name of The NetBSD Foundation nor the names of its
     21  *    contributors may be used to endorse or promote products derived
     22  *    from this software without specific prior written permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     25  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,  BUT NOT LIMITED
     26  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     27  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     28  * BE LIABLE FOR ANY DIRECT, INDIRECT,  INCIDENTAL,  SPECIAL,  EXEMPLARY,  OR
     29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,  PROCUREMENT OF
     30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,  OR PROFITS; OR BUSINESS
     31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     32  * CONTRACT, STRICT LIABILITY,  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     34  * POSSIBILITY OF SUCH DAMAGE.
     35  */
     36 
     37 #include	<machine/asm.h>
     38 
     39 	.file	"bzero.c"
     40 ENTRY(bzero)
     41 	mr	5, 4		# translate to memcpy signature
     42 	li	4, 0		# add missing memcpy param
     43 ENTRY(memset)
     44 	cmpldi	7, 5, 7		# only optimize if len >= 8
     45 	mr	9, 3
     46 	ble	7, 2f
     47 	rldicl.	0, 3, 0, 61	# only optimize if aligned
     48 	beq	0, 4f
     49 2:
     50 	cmpdi	7, 5, 0
     51 	beqlr	7
     52 3:
     53 	mtctr	5
     54 	rldicl	0, 4, 0, 56
     55 	.p2align 4, , 15
     56 2:
     57 	stb	0, 0(9)		# byte-at-a-time loop
     58 	addi	9, 9, 1
     59 	bdnz	2b
     60 	blr			# done
     61 4:
     62 	rldicl	4, 4, 0, 56	# construct parallel store
     63 	cmpldi	7, 5, 31
     64 	mr	10, 3
     65 	sldi	0, 4, 8
     66 	or	0, 0, 4
     67 	sldi	9, 0, 16
     68 	or	0, 0, 9
     69 	sldi	11, 0, 32
     70 	or	0, 0, 11
     71 	ble	7, 5f
     72 	addi	9, 5, -32
     73 	srdi	9, 9, 5
     74 	addi	9, 9, 1
     75 	mtctr	9
     76 	.p2align 4, , 15
     77 2:
     78 	std	0, 0(10)	# 8-way + unrolled store loop
     79 	std	0, 8(10)
     80 	addi	5, 5, -32	# schedule count decrement
     81 	std	0, 16(10)
     82 	std	0, 24(10)
     83 	addi	10, 10, 32
     84 	bdnz	2b
     85 	cmpldi	7, 5, 7
     86 	ble	7, 8f
     87 5:
     88 	addi	9, 5, -8
     89 	srdi	9, 9, 3
     90 	addi	9, 9, 1
     91 	mtctr	9
     92 	.p2align 4, , 15
     93 14:
     94 	std	0, 0(10)	# 8-way not-unrolled loop
     95 	addi	5, 5, -8
     96 	addi	10, 10, 8
     97 	bdnz	14b
     98 8:
     99 	cmpdi	7, 5, 0
    100 	mr	9, 10
    101 	bne	7, 3b
    102 	blr
    103 	.long	0
    104 	.byte	0, 0, 0, 0, 0, 0, 0, 0
    105 	.size	.memset, .-.memset
    106