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sbrk.S revision 1.1 
      1 /*-
      2  * Copyright (c) 1991, 1993
      3  *	The Regents of the University of California.  All rights reserved.
      4  *
      5  * This code is derived from software contributed to Berkeley by
      6  * Ralph Campbell.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  * 3. All advertising materials mentioning features or use of this software
     17  *    must display the following acknowledgement:
     18  *	This product includes software developed by the University of
     19  *	California, Berkeley and its contributors.
     20  * 4. Neither the name of the University nor the names of its contributors
     21  *    may be used to endorse or promote products derived from this software
     22  *    without specific prior written permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     34  * SUCH DAMAGE.
     35  */
     36 
     37 #include "SYS.h"
     38 
     39 #if defined(LIBC_SCCS) && !defined(lint)
     40 	ASMSTR("from: @(#)sbrk.s	8.1 (Berkeley) 6/4/93")
     41 	ASMSTR("$Id: sbrk.S,v 1.1 1994/05/24 07:13:18 glass Exp $")
     42 #endif /* LIBC_SCCS and not lint */
     43 
     44 #define	SYS_brk		17
     45 
     46 	.data
     47 	.globl	minbrk
     48 minbrk:
     49 	.word	end
     50 	.globl	curbrk
     51 curbrk:
     52 	.word	end
     53 	.text
     54 
     55 LEAF(sbrk)
     56 	lw	v1, curbrk
     57 	li	v0, SYS_brk
     58 	addu	a0, a0, v1	# compute current break
     59 	syscall
     60 	bne	a3, zero, 1f
     61 	move	v0, v1		# return old val of _curbrk from above
     62 	sw	a0, curbrk	# save current val of _curbrk from above
     63 	j	ra
     64 1:
     65 	j	_cerror
     66 END(sbrk)
     67