MdeModulePkg EbcDxe: Convert X64/EbcLowLevel.asm to NASM
The BaseTools/Scripts/ConvertMasmToNasm.py script was used to convert
X64/EbcLowLevel.asm to X64/EbcLowLevel.nasm
And, manually update nasm code to use mov rcx, dword value and generate
the same assembly code with rcx register to asm code.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
diff --git a/MdeModulePkg/Universal/EbcDxe/EbcDxe.inf b/MdeModulePkg/Universal/EbcDxe/EbcDxe.inf
index 44558aa..15dc01c 100644
--- a/MdeModulePkg/Universal/EbcDxe/EbcDxe.inf
+++ b/MdeModulePkg/Universal/EbcDxe/EbcDxe.inf
@@ -45,6 +45,7 @@
[Sources.X64]
X64/EbcSupport.c
+ X64/EbcLowLevel.nasm
X64/EbcLowLevel.S
X64/EbcLowLevel.asm
diff --git a/MdeModulePkg/Universal/EbcDxe/X64/EbcLowLevel.nasm b/MdeModulePkg/Universal/EbcDxe/X64/EbcLowLevel.nasm
new file mode 100644
index 0000000..19299a7
--- /dev/null
+++ b/MdeModulePkg/Universal/EbcDxe/X64/EbcLowLevel.nasm
@@ -0,0 +1,242 @@
+;/** @file
+;
+; This code provides low level routines that support the Virtual Machine.
+; for option ROMs.
+;
+; Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
+; Copyright (c) 2014 Hewlett-Packard Development Company, L.P.<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.
+;---------------------------------------------------------------------------
+
+DEFAULT REL
+SECTION .text
+
+extern ASM_PFX(CopyMem)
+extern ASM_PFX(EbcInterpret)
+extern 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.
+;****************************************************************************
+; INT64 EbcLLCALLEXNative(UINTN FuncAddr, UINTN NewStackPointer, VOID *FramePtr)
+global ASM_PFX(EbcLLCALLEXNative)
+ASM_PFX(EbcLLCALLEXNative):
+ push rbp
+ push rbx
+ mov rbp, rsp
+ ; Function prolog
+
+ ; Copy FuncAddr to a preserved register.
+ mov rbx, rcx
+
+ ; Set stack pointer to new value
+ sub r8, rdx
+
+ ;
+ ; 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 r8, 0x20
+ jae skip_expansion
+ mov r8, dword 0x20
+skip_expansion:
+
+ sub rsp, r8
+
+ ;
+ ; 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 rsp, ~ 0xf
+
+ mov rcx, rsp
+ sub rsp, 0x20
+ call ASM_PFX(CopyMem)
+ add rsp, 0x20
+
+ ; Considering the worst case, load 4 potiential arguments
+ ; into registers.
+ mov rcx, qword [rsp]
+ mov rdx, qword [rsp+0x8]
+ mov r8, qword [rsp+0x10]
+ mov r9, qword [rsp+0x18]
+
+ ; Now call the external routine
+ call rbx
+
+ ; Function epilog
+ mov rsp, rbp
+ pop rbx
+ pop rbp
+ ret
+
+;****************************************************************************
+; EbcLLEbcInterpret
+;
+; Begin executing an EBC image.
+;****************************************************************************
+; UINT64 EbcLLEbcInterpret(VOID)
+global ASM_PFX(EbcLLEbcInterpret)
+ASM_PFX(EbcLLEbcInterpret):
+ ;
+ ;; mov rax, ca112ebccall2ebch
+ ;; mov r10, EbcEntryPoint
+ ;; mov r11, EbcLLEbcInterpret
+ ;; jmp r11
+ ;
+ ; Caller uses above instruction to jump here
+ ; The stack is below:
+ ; +-----------+
+ ; | RetAddr |
+ ; +-----------+
+ ; |EntryPoint | (R10)
+ ; +-----------+
+ ; | Arg1 | <- RDI
+ ; +-----------+
+ ; | Arg2 |
+ ; +-----------+
+ ; | ... |
+ ; +-----------+
+ ; | Arg16 |
+ ; +-----------+
+ ; | Dummy |
+ ; +-----------+
+ ; | RDI |
+ ; +-----------+
+ ; | RSI |
+ ; +-----------+
+ ; | RBP | <- RBP
+ ; +-----------+
+ ; | RetAddr | <- RSP is here
+ ; +-----------+
+ ; | Scratch1 | (RCX) <- RSI
+ ; +-----------+
+ ; | Scratch2 | (RDX)
+ ; +-----------+
+ ; | Scratch3 | (R8)
+ ; +-----------+
+ ; | Scratch4 | (R9)
+ ; +-----------+
+ ; | Arg5 |
+ ; +-----------+
+ ; | Arg6 |
+ ; +-----------+
+ ; | ... |
+ ; +-----------+
+ ; | Arg16 |
+ ; +-----------+
+ ;
+
+ ; save old parameter to stack
+ mov [rsp + 0x8], rcx
+ mov [rsp + 0x10], rdx
+ mov [rsp + 0x18], r8
+ mov [rsp + 0x20], r9
+
+ ; Construct new stack
+ push rbp
+ mov rbp, rsp
+ push rsi
+ push rdi
+ push rbx
+ sub rsp, 0x80
+ push r10
+ mov rsi, rbp
+ add rsi, 0x10
+ mov rdi, rsp
+ add rdi, 8
+ mov rcx, dword 16
+ rep movsq
+
+ ; build new paramater calling convention
+ mov r9, [rsp + 0x18]
+ mov r8, [rsp + 0x10]
+ mov rdx, [rsp + 0x8]
+ mov rcx, r10
+
+ ; call C-code
+ call ASM_PFX(EbcInterpret)
+ add rsp, 0x88
+ pop rbx
+ pop rdi
+ pop rsi
+ pop rbp
+ ret
+
+;****************************************************************************
+; EbcLLExecuteEbcImageEntryPoint
+;
+; Begin executing an EBC image.
+;****************************************************************************
+; UINT64 EbcLLExecuteEbcImageEntryPoint(VOID)
+global ASM_PFX(EbcLLExecuteEbcImageEntryPoint)
+ASM_PFX(EbcLLExecuteEbcImageEntryPoint):
+ ;
+ ;; mov rax, ca112ebccall2ebch
+ ;; mov r10, EbcEntryPoint
+ ;; mov r11, EbcLLExecuteEbcImageEntryPoint
+ ;; jmp r11
+ ;
+ ; Caller uses above instruction to jump here
+ ; The stack is below:
+ ; +-----------+
+ ; | RetAddr |
+ ; +-----------+
+ ; |EntryPoint | (R10)
+ ; +-----------+
+ ; |ImageHandle|
+ ; +-----------+
+ ; |SystemTable|
+ ; +-----------+
+ ; | Dummy |
+ ; +-----------+
+ ; | Dummy |
+ ; +-----------+
+ ; | RetAddr | <- RSP is here
+ ; +-----------+
+ ; |ImageHandle| (RCX)
+ ; +-----------+
+ ; |SystemTable| (RDX)
+ ; +-----------+
+ ;
+
+ ; build new paramater calling convention
+ mov r8, rdx
+ mov rdx, rcx
+ mov rcx, r10
+
+ ; call C-code
+ sub rsp, 0x28
+ call ASM_PFX(ExecuteEbcImageEntryPoint)
+ add rsp, 0x28
+ ret
+
