diff options
Diffstat (limited to 'MdeModulePkg/Universal/EbcDxe/Ia32/EbcLowLevel.asm')
| -rw-r--r-- | MdeModulePkg/Universal/EbcDxe/Ia32/EbcLowLevel.asm | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/MdeModulePkg/Universal/EbcDxe/Ia32/EbcLowLevel.asm b/MdeModulePkg/Universal/EbcDxe/Ia32/EbcLowLevel.asm new file mode 100644 index 0000000000..4249241e7d --- /dev/null +++ b/MdeModulePkg/Universal/EbcDxe/Ia32/EbcLowLevel.asm @@ -0,0 +1,163 @@ + page ,132
+ title VM ASSEMBLY LANGUAGE ROUTINES
+;****************************************************************************
+;*
+;* Copyright (c) 2006 - 2007, Intel Corporation
+;* 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.
+;*
+;****************************************************************************
+;****************************************************************************
+; REV 1.0
+;****************************************************************************
+;
+; Rev Date Description
+; --- -------- ------------------------------------------------------------
+; 1.0 03/14/01 Initial creation of file.
+;
+;****************************************************************************
+
+;* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+; This code provides low level routines that support the Virtual Machine
+; for option ROMs.
+;* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+
+;---------------------------------------------------------------------------
+; Equate files needed.
+;---------------------------------------------------------------------------
+
+.XLIST
+
+.LIST
+
+;---------------------------------------------------------------------------
+; Assembler options
+;---------------------------------------------------------------------------
+
+.686p
+.model flat
+.code
+;---------------------------------------------------------------------------
+;;GenericPostSegment SEGMENT USE16
+;---------------------------------------------------------------------------
+CopyMem PROTO C Destination:PTR DWORD, Source:PTR DWORD, Count:DWORD
+
+;****************************************************************************
+; EbcLLCALLEXNative
+;
+; This function is called to execute an EBC CALLEX instruction
+; to native code.
+; This instruction requires that we thunk out to external native
+; code. For IA32, we simply switch stacks 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)
+_EbcLLCALLEXNative PROC NEAR PUBLIC
+ push ebp
+ push ebx
+ mov ebp, esp ; standard function prolog
+
+ ; Get function address in a register
+ ; mov ecx, FuncAddr => mov ecx, dword ptr [FuncAddr]
+ mov ecx, dword ptr [esp]+0Ch
+
+ ; Set stack pointer to new value
+ ; mov eax, NewStackPointer => mov eax, dword ptr [NewSp]
+ mov eax, dword ptr [esp] + 14h
+ mov edx, dword ptr [esp] + 10h
+ sub eax, edx
+ sub esp, eax
+ mov ebx, esp
+ push ecx
+ push eax
+ push edx
+ push ebx
+ call CopyMem
+ pop eax
+ pop eax
+ pop eax
+ pop ecx
+
+ ; Now call the external routine
+ call ecx
+
+ ; ebp is preserved by the callee. In this function it
+ ; equals the original esp, so set them equal
+ mov esp, ebp
+
+ ; Standard function epilog
+ mov esp, ebp
+ pop ebx
+ pop ebp
+ ret
+_EbcLLCALLEXNative ENDP
+
+
+; 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.
+;
+_EbcLLGetEbcEntryPoint PROC NEAR PUBLIC
+ ret
+_EbcLLGetEbcEntryPoint ENDP
+
+;/*++
+;
+;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()
+_EbcLLGetStackPointer PROC NEAR PUBLIC
+ mov eax, esp ; get current stack pointer
+ add eax, 4 ; stack adjusted by this much when we were called
+ ret
+_EbcLLGetStackPointer ENDP
+
+; 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.
+;
+_EbcLLGetReturnValue PROC NEAR PUBLIC
+ ret
+_EbcLLGetReturnValue ENDP
+
+END
|