/*      $NetBSD: swapcontext.S,v 1.5 2014/08/13 15:41:21 joerg Exp $    */

/*-
 * Copyright (c) 2001 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Klaus Klein.
 *
 * 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"

#if defined(LIBC_SCCS) && !defined(lint)
        .text
        .asciz "$NetBSD: swapcontext.S,v 1.5 2014/08/13 15:41:21 joerg Exp $"
#endif /* LIBC_SCCS && !lint */

ENTRY(swapcontext)
        mc_off  = 56                            # offset of uc_mcontext
        stdu    %r1,-SF_SZ(%r1)                 # set up new stack frame
        mflr    %r0
        std     %r0,(SF_SZ+SF_LR)(%r1)          # save link register
        std     %r3,SF_PARAM(%r1)               # must save oucp (was 8)
        std     %r4,SF_PARAM+8(%r1)             # must save ucp (was 12)
        bl      ._getcontext                    # getcontext(oucp)
        nop
        cmpdi   %r3,0
        bne     1f
        ld      %r11,SF_PARAM(%r1)              # load oucp for adjustment
        ld      %r0,SF_SZ+SF_LR(%r1)            # get LR back
        std     %r0,mc_off+34*8(%r11)   #       pc <- lr
        la      %r0,16(%r1)
        std     %r0,mc_off+1*8(%r11)            # adjust sp
        ld      %r3,SF_PARAM+8(%r1)             # load ucp
        bl      PIC_PLT(_C_LABEL(setcontext))   # setcontext(ucp)
        nop
1:
        ld      %r0,SF_SZ+SF_LR(%r1)
        mtlr    %r0
        la      %r1,SF_SZ(%r1)
        blr