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#/** @file
#
# This code provides low level routines that support the Virtual Machine
# for option ROMs.
#
# Copyright (c) 2007 - 2008, Intel Corporation. <BR>
# All rights reserved. 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.
#---------------------------------------------------------------------------
#---------------------------------------------------------------------------
##GenericPostSegment SEGMENT USE16
#---------------------------------------------------------------------------
#****************************************************************************
# 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.
#****************************************************************************
.global _CopyMem;
# VOID EbcLLCALLEXNative(UINTN FuncAddr, UINTN NewStackPointer, VOID *FramePtr)
.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 %r8, %rdx
sub %rsp, %r8
mov %rsp, %rcx
sub %rsp, 0x20
call ASM_PFX(CopyMem)
add %rsp, 0x20
# Considering the worst case, load 4 potiential arguments
# into registers.
mov (%rsp), %rcx
mov 8(%rsp), %rdx
mov 10(%rsp), %r8
mov 18(%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.
#
.global ASM_PFX(EbcLLGetEbcEntryPoint);
ASM_PFX(EbcLLGetEbcEntryPoint):
ret
#/*++
#
#Routine Description:
#
# Return the caller's value of the stack pointer.
#
#Arguments:
#
# None.
#
#Returns:
#
# The current value of the stack pointer for the caller. We
# adjust it by 4 here because when they called us, the return address
# is put on the stack, thereby lowering it by 4 bytes.
#
#--*/
# UINTN EbcLLGetStackPointer()
.global ASM_PFX(EbcLLGetStackPointer);
ASM_PFX(EbcLLGetStackPointer):
mov %rsp, %rax
# Stack adjusted by this much when we were called,
# For this function, it's 4.
add $4, %rax
ret
.global ASM_PFX(EbcLLGetReturnValue);
ASM_PFX(EbcLLGetReturnValue):
# UINT64 EbcLLGetReturnValue(VOID);
# Routine Description:
# When EBC calls native, on return the VM has to stuff the return
# value into a VM register. It's assumed here that the value is still
# in the register, so simply return and the caller should get the
# return result properly.
#
# Arguments:
# None.
#
# Returns:
# The unmodified value returned by the native code.
#
ret
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