1. Remove .extern from GCC assembly.

[mirror_edk2.git] / MdeModulePkg / Universal / EbcDxe / X64 / EbcLowLevel.S

#/** @file\r
#  \r
#    This code provides low level routines that support the Virtual Machine\r
#   for option ROMs.\r
#  \r
#  Copyright (c) 2007 - 2008, Intel Corporation. <BR>\r
#  All rights reserved. This program and the accompanying materials\r
#  are licensed and made available under the terms and conditions of the BSD License\r
#  which accompanies this distribution.  The full text of the license may be found at\r
#  http://opensource.org/licenses/bsd-license.php\r
#  \r
#  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
#  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
#  \r
#**/\r
\r
#---------------------------------------------------------------------------\r
# Equate files needed.\r
#---------------------------------------------------------------------------\r
\r
#---------------------------------------------------------------------------\r
##GenericPostSegment      SEGMENT USE16\r
#---------------------------------------------------------------------------\r
\r
#****************************************************************************\r
# EbcLLCALLEX\r
#\r
# This function is called to execute an EBC CALLEX instruction.\r
# This instruction requires that we thunk out to external native\r
# code. For x64, we switch stacks, copy the arguments to the stack\r
# and jump to the specified function.\r
# On return, we restore the stack pointer to its original location.\r
#\r
# Destroys no working registers.\r
#****************************************************************************\r
ASM_GLOBAL _CopyMem;\r
\r
# VOID EbcLLCALLEXNative(UINTN FuncAddr, UINTN NewStackPointer, VOID *FramePtr)\r
ASM_GLOBAL ASM_PFX(EbcLLCALLEXNative);\r
ASM_PFX(EbcLLCALLEXNative):\r
      push   %rbp\r
      push   %rbx\r
      mov    %rsp, %rbp\r
      # Function prolog\r
\r
      # Copy FuncAddr to a preserved register.\r
      mov    %rcx, %rbx\r
\r
      # Set stack pointer to new value\r
      sub    %r8,  %rdx\r
      sub    %rsp, %r8\r
      mov    %rsp, %rcx\r
      sub    %rsp, 0x20\r
      call   ASM_PFX(CopyMem)\r
      add    %rsp, 0x20\r
\r
      # Considering the worst case, load 4 potiential arguments\r
      # into registers.\r
      mov    (%rsp), %rcx\r
      mov    8(%rsp), %rdx\r
      mov    10(%rsp), %r8\r
      mov    18(%rsp), %r9\r
\r
      # Now call the external routine\r
      call  *%rbx\r
\r
      # Function epilog\r
      mov      %rbp, %rsp\r
      pop      %rbx\r
      pop      %rbp\r
      ret\r
\r
\r
# UINTN EbcLLGetEbcEntryPoint(VOID);\r
# Routine Description:\r
#   The VM thunk code stuffs an EBC entry point into a processor\r
#   register. Since we can't use inline assembly to get it from\r
#   the interpreter C code, stuff it into the return value\r
#   register and return.\r
#\r
# Arguments:\r
#     None.\r
#\r
# Returns:\r
#     The contents of the register in which the entry point is passed.\r
#\r
ASM_GLOBAL ASM_PFX(EbcLLGetEbcEntryPoint);\r
ASM_PFX(EbcLLGetEbcEntryPoint):\r
    ret\r
\r
#/*++\r
#\r
#Routine Description:\r
#\r
#  Return the caller's value of the stack pointer.\r
#\r
#Arguments:\r
#\r
#  None.\r
#\r
#Returns:\r
#\r
#  The current value of the stack pointer for the caller. We\r
#  adjust it by 4 here because when they called us, the return address\r
#  is put on the stack, thereby lowering it by 4 bytes.\r
#\r
#--*/\r
\r
# UINTN EbcLLGetStackPointer()\r
ASM_GLOBAL ASM_PFX(EbcLLGetStackPointer);\r
ASM_PFX(EbcLLGetStackPointer):\r
    mov    %rsp, %rax\r
    # Stack adjusted by this much when we were called,\r
    # For this function, it's 4.\r
    add   $4, %rax\r
    ret\r
\r
ASM_GLOBAL ASM_PFX(EbcLLGetReturnValue);\r
ASM_PFX(EbcLLGetReturnValue):\r
# UINT64 EbcLLGetReturnValue(VOID);\r
# Routine Description:\r
#   When EBC calls native, on return the VM has to stuff the return\r
#   value into a VM register. It's assumed here that the value is still\r
#    in the register, so simply return and the caller should get the\r
#   return result properly.\r
#\r
# Arguments:\r
#     None.\r
#\r
# Returns:\r
#     The unmodified value returned by the native code.\r
#\r
    ret\r