MdeModulePkg/Universal/Ebc/Dxe/x64/EbcLowLevel.asm

   1   page    ,132
   2   title   VM ASSEMBLY LANGUAGE ROUTINES
   3 ;****************************************************************************
   4 ;*
   5 ;*  Copyright (c) 2006, Intel Corporation
   6 ;*  All rights reserved. This program and the accompanying materials
   7 ;*  are licensed and made available under the terms and conditions of the BSD License
   8 ;*  which accompanies this distribution.  The full text of the license may be found at
   9 ;*  http://opensource.org/licenses/bsd-license.php
  10 ;*
  11 ;*  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12 ;*  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13 ;*
  14 ;****************************************************************************
  15 ;****************************************************************************
  16 ;                                   REV 1.0
  17 ;****************************************************************************
  18 ;
  19 ; Rev  Date      Description
  20 ; ---  --------  ------------------------------------------------------------
  21 ; 1.0  05/09/12  Initial creation of file.
  22 ;
  23 ;****************************************************************************
  24
  25 ;* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
  26 ; This code provides low level routines that support the Virtual Machine
  27 ; for option ROMs.
  28 ;* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
  29
  30 ;---------------------------------------------------------------------------
  31 ; Equate files needed.
  32 ;---------------------------------------------------------------------------
  33
  34 text SEGMENT
  35
  36 ;---------------------------------------------------------------------------
  37 ;;GenericPostSegment      SEGMENT USE16
  38 ;---------------------------------------------------------------------------
  39
  40 ;****************************************************************************
  41 ; EbcLLCALLEX
  42 ;
  43 ; This function is called to execute an EBC CALLEX instruction.
  44 ; This instruction requires that we thunk out to external native
  45 ; code. For x64, we switch stacks, copy the arguments to the stack
  46 ; and jump to the specified function.
  47 ; On return, we restore the stack pointer to its original location.
  48 ;
  49 ; Destroys no working registers.
  50 ;****************************************************************************
  51 ; VOID EbcLLCALLEXNative(UINTN FuncAddr, UINTN NewStackPointer, VOID *FramePtr)
  52
  53 CopyMem  PROTO  Destination:PTR DWORD, Source:PTR DWORD, Count:DWORD
  54
  55
  56 EbcLLCALLEXNative        PROC    NEAR    PUBLIC
  57       push   rbp
  58       push   rbx
  59       mov    rbp, rsp
  60       ; Function prolog
  61
  62       ; Copy FuncAddr to a preserved register.
  63       mov    rbx, rcx
  64
  65       ; Set stack pointer to new value
  66       sub    r8,  rdx
  67       sub    rsp, r8
  68       mov    rcx, rsp
  69       sub    rsp, 20h
  70       call   CopyMem
  71       add    rsp, 20h
  72
  73       ; Considering the worst case, load 4 potiential arguments
  74       ; into registers.
  75       mov    rcx, qword ptr [rsp]
  76       mov    rdx, qword ptr [rsp+8h]
  77       mov    r8,  qword ptr [rsp+10h]
  78       mov    r9,  qword ptr [rsp+18h]
  79
  80       ; Now call the external routine
  81       call  rbx
  82
  83       ; Function epilog
  84       mov      rsp, rbp
  85       pop      rbx
  86       pop      rbp
  87       ret
  88 EbcLLCALLEXNative    ENDP
  89
  90
  91 ; UINTN EbcLLGetEbcEntryPoint(VOID);
  92 ; Routine Description:
  93 ;   The VM thunk code stuffs an EBC entry point into a processor
  94 ;   register. Since we can't use inline assembly to get it from
  95 ;   the interpreter C code, stuff it into the return value
  96 ;   register and return.
  97 ;
  98 ; Arguments:
  99 ;     None.
 100 ;
 101 ; Returns:
 102 ;     The contents of the register in which the entry point is passed.
 103 ;
 104 EbcLLGetEbcEntryPoint        PROC    NEAR    PUBLIC
 105     ret
 106 EbcLLGetEbcEntryPoint    ENDP
 107
 108 ;/*++
 109 ;
 110 ;Routine Description:
 111 ;
 112 ;  Return the caller's value of the stack pointer.
 113 ;
 114 ;Arguments:
 115 ;
 116 ;  None.
 117 ;
 118 ;Returns:
 119 ;
 120 ;  The current value of the stack pointer for the caller. We
 121 ;  adjust it by 4 here because when they called us, the return address
 122 ;  is put on the stack, thereby lowering it by 4 bytes.
 123 ;
 124 ;--*/
 125
 126 ; UINTN EbcLLGetStackPointer()
 127 EbcLLGetStackPointer        PROC    NEAR    PUBLIC
 128     mov    rax, rsp      ; get current stack pointer
 129     ; Stack adjusted by this much when we were called,
 130     ; For this function, it's 4.
 131     add   rax, 4
 132     ret
 133 EbcLLGetStackPointer    ENDP
 134
 135 ; UINT64 EbcLLGetReturnValue(VOID);
 136 ; Routine Description:
 137 ;   When EBC calls native, on return the VM has to stuff the return
 138 ;   value into a VM register. It's assumed here that the value is still
 139 ;    in the register, so simply return and the caller should get the
 140 ;   return result properly.
 141 ;
 142 ; Arguments:
 143 ;     None.
 144 ;
 145 ; Returns:
 146 ;     The unmodified value returned by the native code.
 147 ;
 148 EbcLLGetReturnValue   PROC    NEAR    PUBLIC
 149     ret
 150 EbcLLGetReturnValue    ENDP
 151
 152 text  ENDS
 153 END
 154