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swapcontext.S revision 1.4 
      1 /*	$NetBSD: swapcontext.S,v 1.4 2008/04/28 20:22:57 martin Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2001 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Klaus Klein.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include "SYS.h"
     33 
     34 #if defined(LIBC_SCCS) && !defined(lint)
     35 	RCSID("$NetBSD: swapcontext.S,v 1.4 2008/04/28 20:22:57 martin Exp $")
     36 #endif /* LIBC_SCCS && !lint */
     37 
     38 	.register	%g2,#scratch
     39 
     40 ENTRY(swapcontext)
     41 	mov	%o0, %o2			/* must save pointer */
     42 	mov	%o1, %o3			/* must save pointer */
     43 	mov	SYS_getcontext, %g1
     44 	t	ST_SYSCALL
     45 	bcc,a	1f
     46 	 stx	%g0, [%o2 + 64 + 11 * 8]	/* gr[_REG_O0] = 0 */
     47 	ERROR()
     48 1:
     49 	add	%o7, 12, %o1
     50 	stx	%o1, [%o2 + 64 + 2 * 8]		/* gr[_REG_nPC] = retaddr + 4 */
     51 	add	%o7, 8, %o1
     52 	stx	%o1, [%o2 + 64 + 1 * 8]		/* gr[_REG_PC] = retaddr */
     53 
     54 	mov	%o3, %o0
     55 	mov	%o1, %g2			/* optimize `return' */
     56 	mov	SYS_setcontext|SYSCALL_G2RFLAG, %g1
     57 	t	ST_SYSCALL
     58 	ERROR()
     59