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brk.S revision 1.16 
      1 /*	$NetBSD: brk.S,v 1.16 2013/07/16 20:49:42 matt Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1990 The Regents of the University of California.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * the Systems Programming Group of the University of Utah Computer
      9  * Science Department.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  * 3. 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 
     36 #include "SYS.h"
     37 
     38 #if defined(LIBC_SCCS) && !defined(lint)
     39 #if 0
     40 	RCSID("from: @(#)brk.s	5.1 (Berkeley) 5/12/90")
     41 #else
     42 	RCSID("$NetBSD: brk.S,v 1.16 2013/07/16 20:49:42 matt Exp $")
     43 #endif
     44 #endif /* LIBC_SCCS and not lint */
     45 
     46 	.globl	_end
     47 	.globl	_C_LABEL(__minbrk)
     48 	.globl	_C_LABEL(__curbrk)
     49 
     50 #ifdef WEAK_ALIAS
     51 WEAK_ALIAS(brk, _brk)
     52 #endif
     53 
     54 	.data
     55 _C_LABEL(__minbrk):
     56 	.long	_end
     57 
     58 	.text
     59 
     60 ENTRY(_brk)
     61 #ifdef	PIC
     62 	lea	(_GLOBAL_OFFSET_TABLE_@GOTPC,%pc),%a1
     63 	movl	_C_LABEL(__minbrk)@GOT:w(%a1),%a0
     64 	movl	(%a0),%d0
     65 #else
     66 	movl	_C_LABEL(__minbrk),%d0
     67 #endif
     68 	cmpl	4(%sp),%d0
     69 	jls	ok
     70 	movl	%d0,4(%sp)
     71 ok:
     72 	movl	#SYS_break,%d0
     73 	trap	#0
     74 	jcs	err
     75 #ifdef	PIC
     76 	movl	_C_LABEL(__curbrk)@GOT:w(%a1),%a0
     77 	movl	4(%sp),(%a0)
     78 #else
     79 	movl	4(%sp),_C_LABEL(__curbrk)
     80 #endif
     81 	clrl	%d0
     82 	rts
     83 err:
     84 	jra	PIC_PLT(CERROR)
     85