source: trunk/libs/newlib/src/libgloss/nds32/_sbrk.S @ 643

Last change on this file since 643 was 444, checked in by satin@…, 6 years ago

add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc

File size: 2.7 KB
Line 
1/*
2Copyright (c) 2013 Andes Technology Corporation.
3All rights reserved.
4
5Redistribution and use in source and binary forms, with or without
6modification, are permitted provided that the following conditions are met:
7
8    Redistributions of source code must retain the above copyright
9    notice, this list of conditions and the following disclaimer.
10
11    Redistributions in binary form must reproduce the above copyright
12    notice, this list of conditions and the following disclaimer in the
13    documentation and/or other materials provided with the distribution.
14
15    The name of the company may not be used to endorse or promote
16    products derived from this software without specific prior written
17    permission.
18
19THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
20AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
22DISCLAIMED.  IN NO EVENT SHALL RED HAT INCORPORATED BE LIABLE FOR ANY
23DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
24(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
26ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29*/
30#include "../syscall.h"
31#include "syscall_extra.h"
32
33        .extern _impure_ptr     /* The first element is _errno.  */
34        .extern _end
35        .global _sbrk
36        .type   _sbrk, @function
37
38        .text
39        .align  2
40_sbrk:
41        /* Get the value stored in heap_end (Top of Heap). If the value is zero,
42           initialize it with the ending of bss section and leave a 1024-byte
43           room to do low memory action.  */
44        l.w     $r1, heap_end
45        bnez    $r1, .L0
46        /* Note: leave 1024 byte to do low memory action.  */
47        la      $r1, _end + 1024
48        s.w     $r1, heap_end
49
50.L0:
51        /* Try to increments heap_end by $r0 bytes. Check if collision happens ?
52           If collision happens, -1 is returned and errno is set to ENOMEM.
53           Otherwise, save new value to heap_end and return the previous
54           heap_end. */
55
56        /* Make sure new heap_end is aligned on 8-byte boundary.  */
57        addi    $r0, $r0, 7
58        srli    $r0, $r0, 3
59        slli    $r0, $r0, 3
60
61        add     $r0, $r1, $r0   /* Set $r0 as new heap_end.  */
62        slt     $r2, $sp, $r0   /* Set $r2 if $sp is lower than heap_end.  */
63        bnez    $r2, .Lerror    /* Branch if collision happens.  */
64
65        s.w     $r0, heap_end   /* Save new value to heap_end.  */
66        move    $r0, $r1        /* Return the previous heap_end.  */
67        ret
68
69.Lerror:
70        movi    $r0, 12
71        l.w     $r15, _impure_ptr
72        swi     $r0, [$r15]     /* Set errno.  */
73        movi    $r0, -1         /* Reture value is -1.  */
74        ret
75
76        .size   _sbrk, .-_sbrk
77        .section        .bss
78        .align  2
79heap_end:
80        .word   0
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