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brk.S revision 1.5 
      1 /*	$NetBSD: brk.S,v 1.5 2003/04/05 23:08:52 bjh21 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. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  *
     35  *	from: @(#)brk.s	5.2 (Berkeley) 12/17/90
     36  */
     37 
     38 #include "SYS.h"
     39 
     40 	.globl	_C_LABEL(end)
     41 	.globl	CURBRK
     42 
     43 #ifdef WEAK_ALIAS
     44 WEAK_ALIAS(brk, _brk)
     45 #endif
     46 
     47 	.data
     48 	.align	0
     49 	.globl	_C_LABEL(__minbrk)
     50 	.type	_C_LABEL(__minbrk),#object
     51 _C_LABEL(__minbrk):
     52 	.word	_C_LABEL(end)
     53 
     54 /*
     55  * Change the data segment size
     56  */
     57 ENTRY(_brk)
     58 #ifdef PIC
     59 	/* Setup the GOT */
     60 	ldr	r3, .Lgot
     61 	add	r3, pc, r3
     62 .L1:
     63 	ldr	r1, .Lminbrk
     64 	ldr	r1, [r3, r1]
     65 #else
     66 	ldr	r1, .Lminbrk
     67 #endif
     68 	/* Get the minimum allowable brk address */
     69 	ldr	r1, [r1]
     70 
     71 	/*
     72 	 * Valid the address specified and set to the minimum
     73 	 * if the address is below minbrk.
     74 	 */
     75 	cmp	r0, r1
     76 	movlt	r0, r1
     77 	mov	r2, r0
     78 	SYSTRAP(break)
     79 	bcs	PIC_SYM(CERROR, PLT)
     80 
     81 #ifdef PIC
     82 	ldr	r1, .Lcurbrk
     83 	ldr	r1, [r3, r1]
     84 #else
     85 	ldr	r1, .Lcurbrk
     86 #endif
     87 	/* Store the new address in curbrk */
     88 	str	r2, [r1]
     89 
     90 	/* Return 0 for success */
     91 	mov	r0, #0x00000000
     92 	mov	r15, r14
     93 
     94 	.align	2
     95 #ifdef PIC
     96 .Lgot:
     97 	.word	_C_LABEL(_GLOBAL_OFFSET_TABLE_) + (. - (.L1+4))
     98 #endif
     99 .Lminbrk:
    100 	.word	PIC_SYM(_C_LABEL(__minbrk), GOT)
    101 .Lcurbrk:
    102 	.word	PIC_SYM(CURBRK, GOT)
    103