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brk.S revision 1.11 
      1 /*	$NetBSD: brk.S,v 1.11 2003/12/26 11:21:48 martin Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1992, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This software was developed by the Computer Systems Engineering group
      8  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
      9  * contributed to Berkeley.
     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  * from: Header: brk.s,v 1.3 92/06/25 12:56:05 mccanne Exp
     36  */
     37 
     38 #include <machine/asm.h>
     39 #if defined(SYSLIBC_SCCS) && !defined(lint)
     40 #if 0
     41 	.asciz "@(#)brk.s	8.1 (Berkeley) 6/4/93"
     42 #else
     43 	RCSID("$NetBSD: brk.S,v 1.11 2003/12/26 11:21:48 martin Exp $")
     44 #endif
     45 #endif /* SYSLIBC_SCCS and not lint */
     46 
     47 #include "SYS.h"
     48 
     49 	.globl	CURBRK
     50 	.globl	_C_LABEL(__minbrk)
     51 	.globl	_end
     52 
     53 #ifdef WEAK_ALIAS
     54 WEAK_ALIAS(brk, _brk)
     55 #endif
     56 
     57 	.data
     58 _C_LABEL(__minbrk):
     59 	.long	_end			! lower brk limit; also for gmon code
     60 	.text
     61 
     62 ENTRY(_brk)
     63 #ifdef PIC
     64 	PIC_PROLOGUE(%o5,%o4)
     65 	ld	[%o5 + _C_LABEL(__minbrk)], %o4
     66 	ld	[%o4], %o1		! %o1 = minbrk
     67 	cmp	%o1, %o0		! if (minbrk > %o0)
     68 	bgu,a	0f
     69 	 mov	%o1, %o0		!	%o0 = minbrk
     70 0:
     71 	mov	%o0, %o2		! save argument to syscall
     72 	mov	SYS_break, %g1
     73 	t	ST_SYSCALL
     74 	bcc,a	1f
     75 	ld	[%o5 + CURBRK], %o4
     76 	ERROR()
     77 1:
     78 	retl				! success, return 0 & record new break
     79 	 st	%o2, [%o4]
     80 #else
     81 	sethi	%hi(_C_LABEL(__minbrk)), %o1	! %o1 = minbrk
     82 	ld	[%o1 + %lo(_C_LABEL(__minbrk))], %o1
     83 	cmp	%o1, %o0		! if (minbrk > %o0)
     84 	bgu,a	0f
     85 	 mov	%o1, %o0		!	%o0 = minbrk
     86 0:
     87 	mov	%o0, %o2		! save argument to syscall
     88 	mov	SYS_break, %g1
     89 	t	ST_SYSCALL
     90 	bcc,a	1f
     91 	 sethi	%hi(CURBRK), %g1
     92 	ERROR()
     93 1:
     94 	retl				! success, return 0 & record new break
     95 	 st	%o2, [%g1 + %lo(CURBRK)]
     96 #endif
     97