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 81