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brk.S revision 1.9 
      1 /*-
      2  * Copyright (c) 1990 The Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * This code is derived from software contributed to Berkeley by
      6  * William Jolitz.
      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  *	from: @(#)brk.s	5.2 (Berkeley) 12/17/90
     37  *	$Id: brk.S,v 1.9 1994/10/26 19:49:45 mycroft Exp $
     38  */
     39 
     40 #if defined(SYSLIBC_SCCS) && !defined(lint)
     41 	.text
     42 	.asciz "$Id: brk.S,v 1.9 1994/10/26 19:49:45 mycroft Exp $"
     43 #endif /* SYSLIBC_SCCS and not lint */
     44 
     45 #include "SYS.h"
     46 
     47 	.globl	_end
     48 	.globl	minbrk
     49 	.globl	curbrk
     50 
     51 	.data
     52 minbrk:	.long	_end
     53 	.text
     54 
     55 ENTRY(brk)
     56 #ifdef PIC
     57 	movl	4(%esp),%ecx
     58 	PIC_PROLOGUE
     59 	movl	PIC_GOT(minbrk),%edx
     60 	PIC_EPILOGUE
     61 	cmpl	%ecx,(%edx)
     62 	jl	1f
     63 	movl	(%edx),%ecx
     64 	movl	%ecx,4(%esp)
     65 1:
     66 	movl	$(SYS_break),%eax
     67 	int	$0x80
     68 	jc	err
     69 	PIC_PROLOGUE
     70 	movl	PIC_GOT(curbrk),%edx	# set up GOT addressing
     71 	PIC_EPILOGUE
     72 	xorl	%eax,%eax
     73 	movl	%ecx,(%edx)
     74 	ret
     75 err:
     76 	jmp	PIC_PLT(cerror)
     77 
     78 #else
     79 
     80 	movl	4(%esp),%ecx
     81 	cmpl	%ecx,minbrk
     82 	jl	1f
     83 	movl	minbrk,%ecx
     84 	movl	%ecx,4(%esp)
     85 1:
     86 	movl	$(SYS_break),%eax
     87 	int	$0x80
     88 	jc	err
     89 	xorl	%eax,%eax
     90 	movl	%ecx,curbrk
     91 	ret
     92 err:
     93 	jmp	cerror
     94 #endif
     95