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#/** @file
#
# This code provides low level routines that support the Virtual Machine
# for option ROMs.
#
# Copyright (c) 2007 - 2011, Intel Corporation. All rights reserved.<BR>
# This program and the accompanying materials
# are licensed and made available under the terms and conditions of the BSD License
# which accompanies this distribution. The full text of the license may be found at
# http://opensource.org/licenses/bsd-license.php
#
# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
#
#**/
#---------------------------------------------------------------------------
# Equate files needed.
#---------------------------------------------------------------------------
ASM_GLOBAL ASM_PFX(CopyMem);
#****************************************************************************
# EbcLLCALLEX
#
# This function is called to execute an EBC CALLEX instruction.
# This instruction requires that we thunk out to external native
# code. For x64, we switch stacks, copy the arguments to the stack
# and jump to the specified function.
# On return, we restore the stack pointer to its original location.
#
# Destroys no working registers.
#****************************************************************************
# VOID EbcLLCALLEXNative(UINTN FuncAddr, UINTN NewStackPointer, VOID *FramePtr)
ASM_GLOBAL ASM_PFX(EbcLLCALLEXNative);
ASM_PFX(EbcLLCALLEXNative):
push %rbp
push %rbx
mov %rsp, %rbp
# Function prolog
# Copy FuncAddr to a preserved register.
mov %rcx, %rbx
# Set stack pointer to new value
sub %rdx, %r8
sub %r8, %rsp
mov %rsp, %rcx
sub $0x20, %rsp
call ASM_PFX(CopyMem)
add $0x20, %rsp
# Considering the worst case, load 4 potiential arguments
# into registers.
mov (%rsp), %rcx
mov 0x8(%rsp), %rdx
mov 0x10(%rsp), %r8
mov 0x18(%rsp), %r9
# Now call the external routine
call *%rbx
# Function epilog
mov %rbp, %rsp
pop %rbx
pop %rbp
ret
# UINTN EbcLLGetEbcEntryPoint(VOID);
# Routine Description:
# The VM thunk code stuffs an EBC entry point into a processor
# register. Since we can't use inline assembly to get it from
# the interpreter C code, stuff it into the return value
# register and return.
#
# Arguments:
# None.
#
# Returns:
# The contents of the register in which the entry point is passed.
#
ASM_GLOBAL ASM_PFX(EbcLLGetEbcEntryPoint);
ASM_PFX(EbcLLGetEbcEntryPoint):
mov %r10, %rax
ret
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