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sbrk.S revision 1.8.16.1 
      1 /*	$NetBSD: sbrk.S,v 1.8.16.1 2007/08/28 17:36:32 matt Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1990 The Regents of the University of California.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  *
     31  *	from: @(#)sbrk.s	5.1 (Berkeley) 4/23/90
     32  */
     33 
     34 #include "SYS.h"
     35 
     36 	.globl	_C_LABEL(end)
     37 
     38 #ifdef WEAK_ALIAS
     39 WEAK_ALIAS(sbrk, _sbrk)
     40 #endif
     41 
     42 	.data
     43 	.align	0
     44 	.globl	CURBRK
     45 	.type	CURBRK,#object
     46 CURBRK:
     47 	.word	_C_LABEL(end)
     48 
     49 /*
     50  * Change the data segment size
     51  */
     52 ENTRY(_sbrk)
     53 	GOT_INIT(r3, .Lgot, .L1)	/* Setup the GOT */
     54 	GOT_GET(r2, r3, .Lcurbrk)	/* Get the current brk address */
     55 	ldr	r1, [r2]
     56 
     57 	/* Calculate new value */
     58 	mov	r3, r0
     59 	add	r0, r0, r1
     60 	SYSTRAP(break)
     61 	_SYSCALL_CERROR
     62 
     63 	/* Store new curbrk value */
     64 	ldr	r0, [r2]
     65 	add	r1, r0, r3
     66 	str	r1, [r2]
     67 
     68 	/* Return old curbrk value */
     69 	RET
     70 
     71 	.align	0
     72 	GOT_INITSYM(.Lgot, .L1)
     73 .Lcurbrk:
     74 	.word	GOT_SYM(CURBRK)
     75 END(_sbrk)
     76