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Fix X64 native function call prolog. Prepare space for at least 4 arguments,

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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.”
 
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Samer El-Haj-Mahmoud elhaj@hp.com 
Reviewed by: Jiewen Yao <Jiewen.Yao@intel.com>
Reviewed by: Feng Tian <Feng.Tian@intel.com>


git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16152 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
Samer El-Haj-Mahmoud elhaj
2014-09-22 05:54:41 +00:00
committed by jyao1
parent c609f3d7f9
commit b15aae9f2e
2 changed files with 56 additions and 1 deletions
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29
MdeModulePkg/Universal/EbcDxe/X64/EbcLowLevel.S
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@@ -3,7 +3,7 @@
# This code provides low level routines that support the Virtual Machine
# for option ROMs.
#
# Copyright (c) 2007 - 2011, Intel Corporation. All rights reserved.<BR>
# 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
@@ -46,7 +46,34 @@ ASM_PFX(EbcLLCALLEXNative):
# 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)