| 1 | /* |
|---|
| 2 | Copyright (c) 2013 Andes Technology Corporation. |
|---|
| 3 | All rights reserved. |
|---|
| 4 | |
|---|
| 5 | Redistribution and use in source and binary forms, with or without |
|---|
| 6 | modification, 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 | |
|---|
| 19 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
|---|
| 20 | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
|---|
| 21 | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
|---|
| 22 | DISCLAIMED. IN NO EVENT SHALL RED HAT INCORPORATED BE LIABLE FOR ANY |
|---|
| 23 | DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
|---|
| 24 | (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
|---|
| 25 | LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
|---|
| 26 | ON 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 |
|---|
| 28 | SOFTWARE, 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 |
|---|
| 79 | heap_end: |
|---|
| 80 | .word 0 |
|---|
