/*      $NetBSD: swapcontext.S,v 1.4 2011/01/25 02:38:15 matt Exp $     */

/*-
 * Copyright (c) 2003 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Matt Thomas.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "SYS.h"

#ifdef LIBC_SCCS
RCSID("$NetBSD: swapcontext.S,v 1.4 2011/01/25 02:38:15 matt Exp $")
#endif

ENTRY(swapcontext, 0)
        clrl    %r0                     /* assume getcontext succeeds */
        chmk    $SYS_getcontext         /* getcontext(oucp) */
        jcc     1f
        jmp     CERROR+2                /* something bad happened */

1:      movl    4(%ap),%r0              /* get oucp */
        addl3   (%ap),$(5+1),%r1        /* size of callframe + arglist (LW) */
        bbs     $13,6(%fp),2f           /* was this a CALLG? */
        movl    $5,%r1                  /* size of callframe (in LW) */
2:      movl    8(%fp),(36+12*4)(%r0)           /* restore AP */
        moval   (%sp)[%r1],(36+13*4)(%r0)       /* restore SP */
        movq    12(%fp),(36+14*4)(%r0)          /* restore FP + PC */

        pushl   8(%ap)
        calls   $1,_C_LABEL(setcontext) /* setcontext(ucp) */
        ret
END(swapcontext)