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resumecontext.S revision 1.3.16.1
      1  1.3.16.1     tron /*	$NetBSD: resumecontext.S,v 1.3.16.1 2006/12/15 13:25:59 tron Exp $	*/
      2       1.2  thorpej 
      3       1.2  thorpej /*-
      4       1.2  thorpej  * Copyright (c) 2001 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  * 3. All advertising materials mentioning features or use of this software
     19       1.2  thorpej  *    must display the following acknowledgement:
     20       1.2  thorpej  *        This product includes software developed by the NetBSD
     21       1.2  thorpej  *        Foundation, Inc. and its contributors.
     22       1.2  thorpej  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23       1.2  thorpej  *    contributors may be used to endorse or promote products derived
     24       1.2  thorpej  *    from this software without specific prior written permission.
     25       1.2  thorpej  *
     26       1.2  thorpej  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27       1.2  thorpej  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28       1.2  thorpej  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29       1.2  thorpej  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30       1.2  thorpej  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31       1.2  thorpej  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32       1.2  thorpej  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33       1.2  thorpej  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34       1.2  thorpej  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35       1.2  thorpej  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36       1.2  thorpej  * POSSIBILITY OF SUCH DAMAGE.
     37       1.2  thorpej  */
     38       1.2  thorpej 
     39       1.2  thorpej #include <machine/asm.h>
     40       1.2  thorpej 
     41       1.2  thorpej #if defined(LIBC_SCCS) && !defined(lint)
     42  1.3.16.1     tron 	RCSID("$NetBSD: resumecontext.S,v 1.3.16.1 2006/12/15 13:25:59 tron Exp $")
     43       1.2  thorpej #endif /* LIBC_SCCS && !lint */
     44       1.2  thorpej 
     45       1.2  thorpej /*
     46       1.2  thorpej  * This assembly-language implementation differs from the (obvious)
     47       1.2  thorpej  * C-language implementation only in not clobbering the previous
     48       1.2  thorpej  * function's return address (us), which is the point of the exercise.
     49       1.2  thorpej  */
     50       1.2  thorpej 
     51       1.2  thorpej ENTRY(_resumecontext)
     52       1.3   kleink 	subl	#(4 + 1024),%sp		/* retaddr preservation + ucontext_t */
     53       1.2  thorpej 	lea	%sp@,%a0
     54       1.2  thorpej 	movl	%a0,%sp@-
     55       1.2  thorpej 	jbsr	PIC_PLT(_C_LABEL(_getcontext))
     56  1.3.16.1     tron 	movl	%sp@(4 + 4),%sp@	/* uc_link */
     57  1.3.16.1     tron 	tstl	%sp@			/* check for NULL */
     58  1.3.16.1     tron 	jne	1f
     59  1.3.16.1     tron 	jbsr	PIC_PLT(_C_LABEL(exit))	/* cleanly exit(0) */
     60  1.3.16.1     tron 	jmp	2f
     61  1.3.16.1     tron 1:	jbsr	PIC_PLT(_C_LABEL(setcontext))
     62  1.3.16.1     tron 	/* NOTREACHED */
     63  1.3.16.1     tron 	/* But just in case... */
     64  1.3.16.1     tron 2:	movl	#-1,%sp@
     65  1.3.16.1     tron 	jbsr	PIC_PLT(_C_LABEL(_exit))
     66       1.2  thorpej 	/* NOTREACHED */
     67