78 lines
2.7 KiB
ArmAsm
78 lines
2.7 KiB
ArmAsm
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/*
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Copyright (c) 2013 Andes Technology Corporation.
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All rights reserved.
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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 are met:
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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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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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The name of the company may not be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND 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 ARE
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DISCLAIMED. IN NO EVENT SHALL RED HAT INCORPORATED BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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Function:
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memcpy - copy memory regions
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Syntax:
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void *memcpy(void *s1, const void *s2, size_t n);
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Description:
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The memcpy function copies n characters from the object pointed to
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by s2 into the object pointed to by s1. If copying takes place
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between objects that overlap, the behavior is undefined.
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Return value:
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The memcpy function returns the value of s1.
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*/
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.text
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.align 2
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.globl memcpy
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.type memcpy, @function
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memcpy:
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/* Corner cases. If *s1 equals *s2
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or size_t is zero, just go return. */
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beq $r0, $r1, .Lend_memcpy
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beqz $r2, .Lend_memcpy
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/* Keep *s1 as return value.
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Set $r3 as how many words to copy.
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Set $r2 as how many bytes are less than a word. */
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move $r5, $r0
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srli $r3, $r2, 2
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andi $r2, $r2, 3
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beqz $r3, .Lbyte_copy
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.Lword_copy:
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/* Do the word copy $r3 times. Then, do the byte copy $r2 times. */
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lmw.bim $r4, [$r1], $r4, 0
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addi $r3, $r3, -1
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smw.bim $r4, [$r5], $r4, 0
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bnez $r3, .Lword_copy /* Loop again ? */
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beqz $r2, .Lend_memcpy /* Fall THRU or go return ? */
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.Lbyte_copy:
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/* Do the byte copy $r2 times. */
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lbi.bi $r4, [$r1], 1
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addi $r2, $r2, -1
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sbi.bi $r4, [$r5], 1
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bnez $r2, .Lbyte_copy /* Loop again ? */
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.Lend_memcpy:
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ret
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.size memcpy, .-memcpy
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