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sbrk.S revision 1.1 
      1 /* $NetBSD: sbrk.S,v 1.1 2014/08/10 05:47:37 matt Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2014 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Matt Thomas of 3am Software Foundry.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include "SYS.h"
     33 
     34 	.globl	_C_LABEL(_end)
     35 
     36 WEAK_ALIAS(sbrk, _sbrk)
     37 
     38 	.data
     39 	.align	3
     40 	.globl	_C_LABEL(__curbrk)
     41 	.hidden	_C_LABEL(__curbrk)
     42 	.type	_C_LABEL(__curbrk),#object
     43 _C_LABEL(__curbrk):
     44 	.xword	_C_LABEL(_end)
     45 	.size	_C_LABEL(_end), 8
     46 
     47 /*
     48  * Change the data segment size
     49  */
     50 ENTRY(_sbrk)
     51 	/* get address or offset to __curbrk */
     52 	adrp	x9, _C_LABEL(__curbrk)
     53 
     54 	/* Get the current brk address */
     55 	ldr	x1, [x9, #:lo12:_C_LABEL(__curbrk)]
     56 
     57 	/* Calculate new value */
     58 	mov	x10, x0
     59 	add	x0, x0, x1
     60 	SYSTRAP(break)
     61 	_INVOKE_CERROR()
     62 
     63 	/* Store new curbrk value */
     64 	ldr	x0, [x9, #:lo12:_C_LABEL(__curbrk)]
     65 	add	x1, x0, x10
     66 	str	x1, [x9, #:lo12:_C_LABEL(__curbrk)]
     67 
     68 	/* Return old curbrk value */
     69 	ret
     70 END(_sbrk)
     71