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freebsd
GitHub Repository: freebsd/freebsd-src
 Path: blob/main/lib/libc/powerpc64/string/strncpy_arch_2_05.S
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/*-

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 * Copyright (c) 2018 Instituto de Pesquisas Eldorado

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 * All rights reserved.

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 *

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 * Redistribution and use in source and binary forms, with or without

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 * modification, are permitted provided that the following conditions

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 * are met:

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 * 1. Redistributions of source code must retain the above copyright

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 *    notice, this list of conditions and the following disclaimer.

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 * 2. Redistributions in binary form must reproduce the above copyright

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 *    notice, this list of conditions and the following disclaimer in the

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 *    documentation and/or other materials provided with the distribution.

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 * 3. Neither the name of the author nor the names of its contributors may

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 *    be used to endorse or promote products derived from this software

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 *

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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND

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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

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 * SUCH DAMAGE.

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 */

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#include <machine/asm.h>

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ENTRY(__strncpy_arch_2_05)

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	stdu	%r1,-40(%r1)

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	mflr	%r0

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	std	%r0,16(%r1)

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	std	%r3,32(%r1)

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	xor	%r6,%r6,%r6	/* fixed 0 reg */

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/* align loop */

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	addi	%r3,%r3,-1

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.Lalign_loop:

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	/* len? */

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	cmpdi	%r5,0

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	beq	.Lexit

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	/* aligned? */

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	andi.	%r0,%r4,7

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	beq	.Ldw_copy

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	/* copy */

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	lbz	%r7,0(%r4)

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	stbu	%r7,1(%r3)

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	addi	%r4,%r4,1

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	addi	%r5,%r5,-1

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	/* zero? */

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	cmpdi	%r7,0

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	beq	.Lzero

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	b	.Lalign_loop

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/* dword copy loop */

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.Ldw_copy:

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	/* prepare src and dst to use load/store and update */

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	addi	%r3,%r3,-7

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	addi	%r4,%r4,-8

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.Ldw_copy_loop:

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	cmpdi	%r5,8

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	blt	.Lbyte_copy

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	ldu	%r0,8(%r4)

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	/* check for 0 */

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	cmpb	%r7,%r0,%r6

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	cmpdi	%r7,0

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	bne	.Lbyte_copy_and_zero

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	/* copy to dst */

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	stdu	%r0,8(%r3)

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	addi	%r5,%r5,-8

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	b	.Ldw_copy_loop

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/* Copy remaining src bytes, zero-out buffer

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 * Note: r5 will be >= 8

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 */

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.Lbyte_copy_and_zero:

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	addi	%r3,%r3,7

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	addi	%r4,%r4,-1

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.Lbyte_copy_and_zero_loop:

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	lbzu	%r7,1(%r4)

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	stbu	%r7,1(%r3)

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	addi	%r5,%r5,-1

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	cmpdi	%r7,0

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	beq	.Lzero

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	b	.Lbyte_copy_and_zero_loop

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/* zero-out remaining dst bytes */

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.Lzero:

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	addi	%r3,%r3,1

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	li	%r4,0

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	/* r5 has len already */

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	bl	memset

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	nop

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	b	.Lexit

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/* copy remaining (< 8) bytes */

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.Lbyte_copy:

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	cmpdi	%r5,0

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	beq	.Lexit

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	addi	%r3,%r3,7

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	addi	%r4,%r4,7

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	mtctr	%r5

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.Lbyte_copy_loop:

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	lbzu	%r7,1(%r4)

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	stbu	%r7,1(%r3)

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	cmpdi	%r7,0

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	/* 0 found: zero out remaining bytes */

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	beq	.Lbyte_copy_zero

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	bdnz	.Lbyte_copy_loop

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	b	.Lexit

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.Lbyte_copy_zero_loop:

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	stbu	%r6,1(%r3)

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.Lbyte_copy_zero:

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	bdnz	.Lbyte_copy_zero_loop

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.Lexit:

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	/* epilogue */

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	ld	%r3,32(%r1)

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	ld	%r0,16(%r1)

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	mtlr	%r0

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	addi	%r1,%r1,40

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	blr

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END(__strncpy_arch_2_05)

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	.section .note.GNU-stack,"",%progbits

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