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resumecontext.S revision 1.5.8.2 
      1  1.5.8.2  martin /*	$NetBSD: resumecontext.S,v 1.5.8.2 2008/04/28 20:22:57 martin Exp $	*/
      2  1.5.8.2  martin 
      3  1.5.8.2  martin /*-
      4  1.5.8.2  martin  * Copyright (c) 2001 The NetBSD Foundation, Inc.
      5  1.5.8.2  martin  * All rights reserved.
      6  1.5.8.2  martin  *
      7  1.5.8.2  martin  * This code is derived from software contributed to The NetBSD Foundation
      8  1.5.8.2  martin  * by Klaus Klein.
      9  1.5.8.2  martin  *
     10  1.5.8.2  martin  * Redistribution and use in source and binary forms, with or without
     11  1.5.8.2  martin  * modification, are permitted provided that the following conditions
     12  1.5.8.2  martin  * are met:
     13  1.5.8.2  martin  * 1. Redistributions of source code must retain the above copyright
     14  1.5.8.2  martin  *    notice, this list of conditions and the following disclaimer.
     15  1.5.8.2  martin  * 2. Redistributions in binary form must reproduce the above copyright
     16  1.5.8.2  martin  *    notice, this list of conditions and the following disclaimer in the
     17  1.5.8.2  martin  *    documentation and/or other materials provided with the distribution.
     18  1.5.8.2  martin  *
     19  1.5.8.2  martin  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  1.5.8.2  martin  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  1.5.8.2  martin  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  1.5.8.2  martin  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  1.5.8.2  martin  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  1.5.8.2  martin  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  1.5.8.2  martin  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  1.5.8.2  martin  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  1.5.8.2  martin  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  1.5.8.2  martin  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  1.5.8.2  martin  * POSSIBILITY OF SUCH DAMAGE.
     30  1.5.8.2  martin  */
     31  1.5.8.2  martin 
     32  1.5.8.2  martin #include <machine/asm.h>
     33  1.5.8.2  martin 
     34  1.5.8.2  martin #if defined(LIBC_SCCS) && !defined(lint)
     35  1.5.8.2  martin 	RCSID("$NetBSD: resumecontext.S,v 1.5.8.2 2008/04/28 20:22:57 martin Exp $")
     36  1.5.8.2  martin #endif /* LIBC_SCCS && !lint */
     37  1.5.8.2  martin 
     38  1.5.8.2  martin /*
     39  1.5.8.2  martin  * This assembly-language implementation differs from the (obvious)
     40  1.5.8.2  martin  * C-language implementation only in not clobbering the previous
     41  1.5.8.2  martin  * function's return address (us), which is the point of the exercise.
     42  1.5.8.2  martin  */
     43  1.5.8.2  martin 
     44  1.5.8.2  martin ENTRY(_resumecontext)
     45  1.5.8.2  martin 	subl	#(4 + 1024),%sp		/* retaddr preservation + ucontext_t */
     46  1.5.8.2  martin 	lea	%sp@,%a0
     47  1.5.8.2  martin 	movl	%a0,%sp@-
     48  1.5.8.2  martin 	jbsr	PIC_PLT(_C_LABEL(_getcontext))
     49  1.5.8.2  martin 	movl	%sp@(4 + 4),%sp@	/* uc_link */
     50  1.5.8.2  martin 	tstl	%sp@			/* check for NULL */
     51  1.5.8.2  martin 	jne	1f
     52  1.5.8.2  martin 	jbsr	PIC_PLT(_C_LABEL(exit))	/* cleanly exit(0) */
     53  1.5.8.2  martin 	jmp	2f
     54  1.5.8.2  martin 1:	jbsr	PIC_PLT(_C_LABEL(setcontext))
     55  1.5.8.2  martin 	/* NOTREACHED */
     56  1.5.8.2  martin 	/* But just in case... */
     57  1.5.8.2  martin 2:	movl	#-1,%sp@
     58  1.5.8.2  martin 	jbsr	PIC_PLT(_C_LABEL(_exit))
     59  1.5.8.2  martin 	/* NOTREACHED */
     60