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resumecontext.S revision 1.8 
      1  1.8  uebayasi /*	$NetBSD: resumecontext.S,v 1.8 2014/05/23 02:34:19 uebayasi Exp $	*/
      2  1.2   thorpej 
      3  1.2   thorpej /*-
      4  1.2   thorpej  * Copyright (c) 1999 The NetBSD Foundation, Inc.
      5  1.2   thorpej  * All rights reserved.
      6  1.2   thorpej  *
      7  1.2   thorpej  * This code is derived from software contributed to The NetBSD Foundation
      8  1.2   thorpej  * by Klaus Klein.
      9  1.2   thorpej  *
     10  1.2   thorpej  * Redistribution and use in source and binary forms, with or without
     11  1.2   thorpej  * modification, are permitted provided that the following conditions
     12  1.2   thorpej  * are met:
     13  1.2   thorpej  * 1. Redistributions of source code must retain the above copyright
     14  1.2   thorpej  *    notice, this list of conditions and the following disclaimer.
     15  1.2   thorpej  * 2. Redistributions in binary form must reproduce the above copyright
     16  1.2   thorpej  *    notice, this list of conditions and the following disclaimer in the
     17  1.2   thorpej  *    documentation and/or other materials provided with the distribution.
     18  1.2   thorpej  *
     19  1.2   thorpej  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  1.2   thorpej  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  1.2   thorpej  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  1.2   thorpej  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  1.2   thorpej  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  1.2   thorpej  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  1.2   thorpej  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  1.2   thorpej  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  1.2   thorpej  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  1.2   thorpej  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  1.2   thorpej  * POSSIBILITY OF SUCH DAMAGE.
     30  1.2   thorpej  */
     31  1.2   thorpej 
     32  1.2   thorpej #include <machine/asm.h>
     33  1.5  drochner #include "SYS.h"
     34  1.2   thorpej 
     35  1.2   thorpej #if defined(LIBC_SCCS) && !defined(lint)
     36  1.8  uebayasi 	RCSID("$NetBSD: resumecontext.S,v 1.8 2014/05/23 02:34:19 uebayasi Exp $")
     37  1.2   thorpej #endif /* LIBC_SCCS && !lint */
     38  1.2   thorpej 
     39  1.2   thorpej /*
     40  1.2   thorpej  * This assembly-language implementation differs from the (obvious)
     41  1.2   thorpej  * C-language implementation only in not clobbering the previous
     42  1.2   thorpej  * function's return address (us), which is the point of the exercise.
     43  1.2   thorpej  */
     44  1.2   thorpej 
     45  1.2   thorpej NENTRY(_resumecontext)	/* profiling prologue would clobber TOS */
     46  1.4    kleink 	leal	-(4 + 776)(%esp),%ecx	/* retaddr + sizeof (ucontext_t) */
     47  1.4    kleink 	andl	$~(0xf),%ecx		/* align on _UC_UCONTEXT_ALIGN */
     48  1.4    kleink 	movl	%ecx,%esp
     49  1.2   thorpej 	PIC_PROLOGUE
     50  1.2   thorpej 	pushl	%ecx
     51  1.7     joerg #ifdef __PIC__
     52  1.2   thorpej 	call	PIC_PLT(_C_LABEL(_getcontext))
     53  1.2   thorpej #else
     54  1.2   thorpej 	call	_C_LABEL(_getcontext)
     55  1.2   thorpej #endif
     56  1.2   thorpej 	addl	$4,%esp
     57  1.2   thorpej 	PIC_EPILOGUE
     58  1.4    kleink 	movl	4(%esp),%ecx		/* uc_link */
     59  1.2   thorpej 	PIC_PROLOGUE
     60  1.5  drochner 	pushl	%ecx	/* argument for exit() or setcontext() */
     61  1.5  drochner 	testl	%ecx,%ecx		/* link end? */
     62  1.5  drochner 	jnz	9f	/* watch out for local label use in PIC_* */
     63  1.5  drochner 
     64  1.5  drochner 	/* normal exit */
     65  1.7     joerg #ifdef __PIC__
     66  1.5  drochner 	call	PIC_PLT(_C_LABEL(exit))
     67  1.5  drochner #else
     68  1.5  drochner 	call	_C_LABEL(exit)
     69  1.5  drochner #endif
     70  1.5  drochner 	/* NOTREACHED */
     71  1.5  drochner 
     72  1.5  drochner 9:
     73  1.7     joerg #ifdef __PIC__
     74  1.2   thorpej 	call	PIC_PLT(_C_LABEL(setcontext))
     75  1.2   thorpej #else
     76  1.2   thorpej 	call	_C_LABEL(setcontext)
     77  1.2   thorpej #endif
     78  1.2   thorpej 	/* NOTREACHED */
     79  1.5  drochner 
     80  1.5  drochner 	/* something is wrong, pull the brake */
     81  1.5  drochner 	pushl	$-1
     82  1.5  drochner 	pushl	%eax	/* unused return address */
     83  1.5  drochner 	SYSTRAP(exit)
     84  1.8  uebayasi END(_resumecontext)
     85