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#/** @file
#
# This code provides low level routines that support the Virtual Machine
# for option ROMs.
#
# Copyright (c) 2007 - 2014, 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);
ASM_GLOBAL ASM_PFX(EbcInterpret);
ASM_GLOBAL ASM_PFX(ExecuteEbcImageEntryPoint);
#****************************************************************************
# 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
#
# Fix X64 native function call prolog. Prepare space for at least 4 arguments,
# even if the native function's arguments are less than 4.
#
# From MSDN x64 Software Conventions, Overview of x64 Calling Conventions:
# "The caller is responsible for allocating space for parameters to the
# callee, and must always allocate sufficient space for the 4 register
# parameters, even if the callee doesn't have that many parameters.
# This aids in the simplicity of supporting C unprototyped functions,
# and vararg C/C++ functions."
#
cmp $0x20, %r8
jae skip_expansion
mov $0x20, %r8
skip_expansion:
sub %r8, %rsp
#
# Fix X64 native function call 16-byte alignment.
#
# From MSDN x64 Software Conventions, Stack Usage:
# "The stack will always be maintained 16-byte aligned, except within
# the prolog (for example, after the return address is pushed)."
#
and $0xFFFFFFFFFFFFFFF0, %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
ASM_GLOBAL ASM_PFX(EbcLLEbcInterpret);
ASM_PFX(EbcLLEbcInterpret):
# save old parameter to stack
mov %rcx, 0x8(%rsp)
mov %rdx, 0x10(%rsp)
mov %r8, 0x18(%rsp)
mov %r9, 0x20(%rsp)
# Construct new stack
push %rbp
mov %rsp, %rbp
push %rsi
push %rdi
push %rbx
sub $0x80, %rsp
push %r10
mov %rbp, %rsi
add $0x10, %rsi
mov %rsp, %rdi
add $0x8, %rdi
mov $0x10, %rcx
rep movsq
# build new paramater calling convention
mov 0x18(%rsp), %r9
mov 0x10(%rsp), %r8
mov 0x8(%rsp), %rdx
mov %r10, %rcx
# call C-code
call ASM_PFX(EbcInterpret)
add $0x88, %esp
pop %rbx
pop %rdi
pop %rsi
pop %rbp
ret
ASM_GLOBAL ASM_PFX(EbcLLExecuteEbcImageEntryPoint);
ASM_PFX(EbcLLExecuteEbcImageEntryPoint):
# build new paramater calling convention
mov %rdx, %r8
mov %rcx, %rdx
mov %r10, %rcx
# call C-code
sub $0x28, %rsp
call ASM_PFX(ExecuteEbcImageEntryPoint)
add $0x28, %rsp
ret
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