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#

# Copyright (c) 2001-2004 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.

#

.text

.global context_save

.global context_restore

#include <libarch/context_offset.h>

## Save current CPU context

#

# Save CPU context to context_t variable

# pointed by the 1st argument. Returns 1 in EAX.

#

context_save:

	movq (%rsp), %rdx     # the caller's return %eip

	# In %edi is passed 1st argument

	movq %rdx, OFFSET_PC(%rdi)

	movq %rsp, OFFSET_SP(%rdi)

	movq %rbx, OFFSET_RBX(%rdi)

	movq %rbp, OFFSET_RBP(%rdi)

	movq %r12, OFFSET_R12(%rdi)

	movq %r13, OFFSET_R13(%rdi)

	movq %r14, OFFSET_R14(%rdi)

	movq %r15, OFFSET_R15(%rdi)

	# Save TLS

	movq %fs:0, %rax

	movq %rax, OFFSET_TLS(%rdi)

	xorq %rax,%rax		# context_save returns 1

	incq %rax

	ret

## Restore current CPU context

#

# Restore CPU context from context_t variable

# pointed by the 1st argument. Returns 0 in EAX.

#

context_restore:

	movq OFFSET_R15(%rdi), %r15

	movq OFFSET_R14(%rdi), %r14

	movq OFFSET_R13(%rdi), %r13

	movq OFFSET_R12(%rdi), %r12

	movq OFFSET_RBP(%rdi), %rbp

	movq OFFSET_RBX(%rdi), %rbx	

	movq OFFSET_SP(%rdi), %rsp   # ctx->sp -> %rsp

	movq OFFSET_PC(%rdi), %rdx

	movq %rdx,(%rsp)

	# Set thread local storage

	movq OFFSET_TLS(%rdi), %rdi   # Set arg1 to TLS addr

	movq $1, %r8

	syscall

	xorq %rax,%rax		# context_restore returns 0

	ret