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brk.S revision 1.8.16.1 
      1 /*	$NetBSD: brk.S,v 1.8.16.1 2007/08/28 17:36:31 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: @(#)brk.s	5.2 (Berkeley) 12/17/90
     32  */
     33 
     34 #include "SYS.h"
     35 
     36 	.globl	_C_LABEL(end)
     37 	.globl	CURBRK
     38 
     39 #ifdef WEAK_ALIAS
     40 WEAK_ALIAS(brk, _brk)
     41 #endif
     42 
     43 	.data
     44 	.align	0
     45 	.globl	_C_LABEL(__minbrk)
     46 	.type	_C_LABEL(__minbrk),#object
     47 _C_LABEL(__minbrk):
     48 	.word	_C_LABEL(end)
     49 
     50 /*
     51  * Change the data segment size
     52  */
     53 ENTRY(_brk)
     54 	GOT_INIT(r3, .Lgot, .L1)	/* Setup the GOT */
     55 	GOT_GET(r1, r3, .Lminbrk)	/* Get the min allowable brk addr */
     56 	ldr	r1, [r1]
     57 
     58 	/*
     59 	 * Valid the address specified and set to the minimum
     60 	 * if the address is below minbrk.
     61 	 */
     62 	cmp	r0, r1
     63 #ifdef __thumb__
     64 	bcs	1f
     65 	mov	r0, r1
     66 1:
     67 #else
     68 	movcc	r0, r1
     69 #endif
     70 	mov	r2, r0
     71 	SYSTRAP(break)
     72 	_SYSCALL_CERROR_CHECK
     73 
     74 	/* Store the new address in curbrk */
     75 	GOT_GET(r1, r3, .Lcurbrk)
     76 	str	r2, [r1]
     77 
     78 	/* Return 0 for success */
     79 	mov	r0, #0
     80 	RET
     81 
     82 	.align	0
     83 	GOT_INITSYM(.Lgot, .L1)
     84 .Lminbrk:
     85 	.word	GOT_SYM(_C_LABEL(__minbrk))
     86 .Lcurbrk:
     87 	.word	GOT_SYM(CURBRK)
     88 END(_brk)
     89