77 lines
2.6 KiB
ArmAsm
77 lines
2.6 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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*/
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#include "../syscall.h"
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#include "syscall_extra.h"
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.extern _end
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.global _sbrk
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.text
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.align 2
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_sbrk:
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/* Get the value stored in heap_end (Top of Heap). If the value is zero,
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initialize it with the ending of bss section and leave a 1024-byte
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room to do low memory action. */
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l.w $r1, heap_end
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bnez $r1, .L0
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/* Note: leave 1024 byte to do low memory action. */
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la $r1, _end + 1024
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s.w $r1, heap_end
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.L0:
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/* Try to increments heap_end by $r0 bytes. Check if collision happens ?
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If collision happens, -1 is returned and errno is set to ENOMEM.
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Otherwise, save new value to heap_end and return the previous
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heap_end. */
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/* Make sure new heap_end is aligned on 8-byte boundary. */
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addi $r0, $r0, 7
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srli $r0, $r0, 3
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slli $r0, $r0, 3
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add $r0, $r1, $r0 /* Set $r0 as new heap_end. */
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slt $r2, $sp, $r0 /* Set $r2 if $sp is lower than heap_end. */
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bnez $r2, .Lerror /* Branch if collision happens. */
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s.w $r0, heap_end /* Save new value to heap_end. */
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move $r0, $r1 /* Return the previous heap_end. */
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ret
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.Lerror:
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movi $r0, 12
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s.w $r0, errno /* Set error code: 12 (ENOMEM) to errno. */
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movi $r0, -1 /* Reture value is -1. */
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ret
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.section .bss
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.align 2
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heap_end:
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.word 0
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