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#
# Copyright (C) 2005 Jakub Jermar
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# - 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.
# - The name of the author may not be used to endorse or promote products
#   derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <arch/context_offset.h>
#include <arch/stack.h>

/**
 * Both context_save_arch() and context_restore_arch() are
 * leaf-optimized procedures. This kind of optimization
 * is very important and prevents any implicit window
 * spill/fill/clean traps in these very core kernel
 * functions.
 */
    
.text   

.global context_save_arch
.global context_restore_arch

.macro CONTEXT_STORE r
    stx %o1, [\r + OFFSET_O1]
    stx %o2, [\r + OFFSET_O2]
    stx %o3, [\r + OFFSET_O3]
    stx %o4, [\r + OFFSET_O4]
    stx %o5, [\r + OFFSET_O5]
    stx %o7, [\r + OFFSET_PC]
    stx %sp, [\r + OFFSET_SP]
    stx %fp, [\r + OFFSET_FP]
.endm

.macro CONTEXT_LOAD r
    ldx [\r + OFFSET_O1], %o1
    ldx [\r + OFFSET_O2], %o2
    ldx [\r + OFFSET_O3], %o3
    ldx [\r + OFFSET_O4], %o4
    ldx [\r + OFFSET_O5], %o5
    ldx [\r + OFFSET_PC], %o7
    ldx [\r + OFFSET_SP], %sp
    ldx [\r + OFFSET_FP], %fp
.endm

context_save_arch:
    CONTEXT_STORE %o0
    retl
    mov 1, %o0      ! context_save_arch returns 1

context_restore_arch:
    #
    # Flush all active windows.
    # This is essential, because CONTEXT_LOAD overwrites
    # %sp of CWP - 1 with the value written to %fp of CWP.
    # Flushing all active windows mitigates this problem
    # as CWP - 1 becomes the overlap window.
    #
    flushw
    
    CONTEXT_LOAD %o0
    retl
    xor %o0, %o0, %o0   ! context_restore_arch returns 0