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sbrk.S revision 1.18 
      1 /*	$NetBSD: sbrk.S,v 1.18 2010/12/12 09:03:06 tsutsui Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1991, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Ralph Campbell.
      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  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  */
     34 
     35 #include "SYS.h"
     36 
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 #if 0
     39 	RCSID("from: @(#)sbrk.s	8.1 (Berkeley) 6/4/93")
     40 #else
     41 	RCSID("$NetBSD: sbrk.S,v 1.18 2010/12/12 09:03:06 tsutsui Exp $")
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 	.globl	_C_LABEL(__curbrk)
     46 	.globl	_C_LABEL(_end)
     47 
     48 #ifdef WEAK_ALIAS
     49 WEAK_ALIAS(sbrk, _sbrk)
     50 #endif
     51 
     52 	.data
     53 _C_LABEL(__curbrk):
     54 	PTR_WORD	_C_LABEL(_end)
     55 	.text
     56 
     57 LEAF(_sbrk)
     58 	PIC_PROLOGUE(_sbrk)
     59 	PTR_LA		t0, _C_LABEL(__curbrk)
     60 	PTR_L		v1, 0(t0)
     61 	PTR_ADDU	a0, a0, v1	# compute current break
     62 	SYSTRAP(break)
     63 	bne		a3, zero, 1f
     64 	move		v0, v1		# return old val of curbrk from above
     65 	PTR_LA		t0, _C_LABEL(__curbrk)
     66 	PTR_S		a0, 0(t0)	# save current val of curbrk from above
     67 	PIC_RETURN()
     68 1:
     69 	PIC_TAILCALL(__cerror)
     70 END(_sbrk)
     71