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brk.S revision 1.2 
      1 /*
      2  * Copyright (c) 1992, 1993
      3  *	The Regents of the University of California.  All rights reserved.
      4  *
      5  * This software was developed by the Computer Systems Engineering group
      6  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
      7  * contributed to Berkeley.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  * 3. All advertising materials mentioning features or use of this software
     18  *    must display the following acknowledgement:
     19  *	This product includes software developed by the University of
     20  *	California, Berkeley and its contributors.
     21  * 4. Neither the name of the University nor the names of its contributors
     22  *    may be used to endorse or promote products derived from this software
     23  *    without specific prior written permission.
     24  *
     25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     35  * SUCH DAMAGE.
     36  *
     37  * from: Header: brk.s,v 1.3 92/06/25 12:56:05 mccanne Exp
     38  * $Id: brk.S,v 1.2 1994/02/10 20:15:56 pk Exp $
     39  */
     40 
     41 #if defined(LIBC_SCCS) && !defined(lint)
     42 	.asciz "@(#)brk.s	8.1 (Berkeley) 6/4/93"
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 #include "SYS.h"
     46 
     47 	.globl	curbrk
     48 	.globl	minbrk
     49 
     50 	.data
     51 minbrk:	.long	_end			! lower brk limit; also for gmon code
     52 	.text
     53 
     54 #ifdef PIC
     55 ENTRY(brk)
     56 	PIC_PROLOGUE(%o5,%o4)
     57 	ld	[%o5 + minbrk], %o4
     58 	ld	[%o4], %o1		! %o1 = minbrk
     59 	cmp	%o1, %o0		! if (minbrk > %o0)
     60 	bg,a	0f
     61 	 mov	%o1, %o0		!	%o0 = minbrk
     62 0:
     63 	mov	%o0, %o2		! save argument to syscall
     64 	mov	SYS_break, %g1
     65 	t	ST_SYSCALL
     66 	bcc,a	1f
     67 	ld	[%o5 + curbrk], %o4
     68 	ERROR()
     69 1:
     70 	retl				! success, return 0 & record new break
     71 	 st	%o2, [%o4]
     72 #else
     73 ENTRY(brk)
     74 	sethi	%hi(minbrk), %o1	! %o1 = minbrk
     75 	ld	[%o1 + %lo(minbrk)], %o1
     76 	cmp	%o1, %o0		! if (minbrk > %o0)
     77 	bg,a	0f
     78 	 mov	%o1, %o0		!	%o0 = minbrk
     79 0:
     80 	mov	%o0, %o2		! save argument to syscall
     81 	mov	SYS_break, %g1
     82 	t	ST_SYSCALL
     83 	bcc,a	1f
     84 	 sethi	%hi(curbrk), %g1
     85 	ERROR()
     86 1:
     87 	retl				! success, return 0 & record new break
     88 	 st	%o2, [%g1 + %lo(curbrk)]
     89 #endif
     90