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Diffstat (limited to 'libgloss/nds32/_sbrk.S')
| -rw-r--r-- | libgloss/nds32/_sbrk.S | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/libgloss/nds32/_sbrk.S b/libgloss/nds32/_sbrk.S new file mode 100644 index 000000000..ae32e8dcd --- /dev/null +++ b/libgloss/nds32/_sbrk.S @@ -0,0 +1,78 @@ +/* +Copyright (c) 2013 Andes Technology Corporation. +All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + + Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + + Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. + + The name of the company may not be used to endorse or promote + products derived from this software without specific prior written + permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +DISCLAIMED. IN NO EVENT SHALL RED HAT INCORPORATED BE LIABLE FOR ANY +DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND +ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +*/ +#include "../syscall.h" +#include "syscall_extra.h" + + .extern _impure_ptr /* The first element is _errno. */ + .extern _end + .global _sbrk + + .text + .align 2 +_sbrk: + /* Get the value stored in heap_end (Top of Heap). If the value is zero, + initialize it with the ending of bss section and leave a 1024-byte + room to do low memory action. */ + l.w $r1, heap_end + bnez $r1, .L0 + /* Note: leave 1024 byte to do low memory action. */ + la $r1, _end + 1024 + s.w $r1, heap_end + +.L0: + /* Try to increments heap_end by $r0 bytes. Check if collision happens ? + If collision happens, -1 is returned and errno is set to ENOMEM. + Otherwise, save new value to heap_end and return the previous + heap_end. */ + + /* Make sure new heap_end is aligned on 8-byte boundary. */ + addi $r0, $r0, 7 + srli $r0, $r0, 3 + slli $r0, $r0, 3 + + add $r0, $r1, $r0 /* Set $r0 as new heap_end. */ + slt $r2, $sp, $r0 /* Set $r2 if $sp is lower than heap_end. */ + bnez $r2, .Lerror /* Branch if collision happens. */ + + s.w $r0, heap_end /* Save new value to heap_end. */ + move $r0, $r1 /* Return the previous heap_end. */ + ret + +.Lerror: + movi $r0, 12 + l.w $r15, _impure_ptr + swi $r0, [$r15] /* Set errno. */ + movi $r0, -1 /* Reture value is -1. */ + ret + + .section .bss + .align 2 +heap_end: + .word 0 |