| 1 | /* |
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| 2 | Copyright (c) 2013 Andes Technology Corporation. |
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| 3 | All rights reserved. |
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| 4 | |
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| 5 | Redistribution and use in source and binary forms, with or without |
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| 6 | modification, are permitted provided that the following conditions are met: |
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| 7 | |
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| 8 | Redistributions of source code must retain the above copyright |
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| 9 | notice, this list of conditions and the following disclaimer. |
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| 10 | |
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| 11 | Redistributions in binary form must reproduce the above copyright |
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| 12 | notice, this list of conditions and the following disclaimer in the |
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| 13 | documentation and/or other materials provided with the distribution. |
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| 14 | |
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| 15 | The name of the company may not be used to endorse or promote |
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| 16 | products derived from this software without specific prior written |
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| 17 | permission. |
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| 18 | |
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| 19 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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| 20 | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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| 21 | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
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| 22 | DISCLAIMED. IN NO EVENT SHALL RED HAT INCORPORATED BE LIABLE FOR ANY |
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| 23 | DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
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| 24 | (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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| 25 | LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
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| 26 | ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 27 | (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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| 28 | SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 29 | |
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| 30 | |
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| 31 | Function: |
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| 32 | memcpy - copy memory regions |
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| 33 | Syntax: |
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| 34 | void *memcpy(void *s1, const void *s2, size_t n); |
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| 35 | Description: |
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| 36 | The memcpy function copies n characters from the object pointed to |
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| 37 | by s2 into the object pointed to by s1. If copying takes place |
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| 38 | between objects that overlap, the behavior is undefined. |
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| 39 | Return value: |
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| 40 | The memcpy function returns the value of s1. |
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| 41 | */ |
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| 42 | .text |
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| 43 | .align 2 |
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| 44 | .globl memcpy |
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| 45 | .type memcpy, @function |
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| 46 | memcpy: |
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| 47 | /* Corner cases. If *s1 equals *s2 |
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| 48 | or size_t is zero, just go return. */ |
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| 49 | beq $r0, $r1, .Lend_memcpy |
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| 50 | beqz $r2, .Lend_memcpy |
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| 51 | |
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| 52 | /* Keep *s1 as return value. |
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| 53 | Set $r3 as how many words to copy. |
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| 54 | Set $r2 as how many bytes are less than a word. */ |
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| 55 | move $r5, $r0 |
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| 56 | srli $r3, $r2, 2 |
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| 57 | andi $r2, $r2, 3 |
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| 58 | beqz $r3, .Lbyte_copy |
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| 59 | |
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| 60 | .Lword_copy: |
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| 61 | /* Do the word copy $r3 times. Then, do the byte copy $r2 times. */ |
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| 62 | lmw.bim $r4, [$r1], $r4, 0 |
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| 63 | addi $r3, $r3, -1 |
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| 64 | smw.bim $r4, [$r5], $r4, 0 |
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| 65 | bnez $r3, .Lword_copy /* Loop again ? */ |
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| 66 | beqz $r2, .Lend_memcpy /* Fall THRU or go return ? */ |
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| 67 | |
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| 68 | .Lbyte_copy: |
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| 69 | /* Do the byte copy $r2 times. */ |
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| 70 | lbi.bi $r4, [$r1], 1 |
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| 71 | addi $r2, $r2, -1 |
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| 72 | sbi.bi $r4, [$r5], 1 |
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| 73 | bnez $r2, .Lbyte_copy /* Loop again ? */ |
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| 74 | |
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| 75 | .Lend_memcpy: |
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| 76 | ret |
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| 77 | .size memcpy, .-memcpy |
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