IntelFsp2Pkg BaseFspSwitchStackLib: Convert Ia32/Stack.asm to NASM

The BaseTools/Scripts/ConvertMasmToNasm.py script was used to convert
Ia32/Stack.asm to Ia32/Stack.nasm

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Liming Gao <liming.gao@intel.com>

IntelFsp2Pkg/Library/BaseFspSwitchStackLib/Ia32/Stack.nasm

@@ -0,0 +1,74 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (c) 2016, 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
+; 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.
+;
+; Abstract:
+;
+;   Switch the stack from temporary memory to permenent memory.
+;
+;------------------------------------------------------------------------------
+
+    SECTION .text
+
+extern ASM_PFX(SwapStack)
+
+;------------------------------------------------------------------------------
+; UINT32
+; EFIAPI
+; Pei2LoaderSwitchStack (
+;   VOID
+;   )
+;------------------------------------------------------------------------------
+global ASM_PFX(Pei2LoaderSwitchStack)
+ASM_PFX(Pei2LoaderSwitchStack):
+    xor     eax, eax
+    jmp     ASM_PFX(FspSwitchStack)
+
+;------------------------------------------------------------------------------
+; UINT32
+; EFIAPI
+; Loader2PeiSwitchStack (
+;   VOID
+;   )
+;------------------------------------------------------------------------------
+global ASM_PFX(Loader2PeiSwitchStack)
+ASM_PFX(Loader2PeiSwitchStack):
+    jmp     ASM_PFX(FspSwitchStack)
+
+;------------------------------------------------------------------------------
+; UINT32
+; EFIAPI
+; FspSwitchStack (
+;   VOID
+;   )
+;------------------------------------------------------------------------------
+global ASM_PFX(FspSwitchStack)
+ASM_PFX(FspSwitchStack):
+    ; Save current contexts
+    push    eax
+    pushfd
+    cli
+    pushad
+    sub     esp, 8
+    sidt    [esp]
+
+    ; Load new stack
+    push    esp
+    call    ASM_PFX(SwapStack)
+    mov     esp, eax
+
+    ; Restore previous contexts
+    lidt    [esp]
+    add     esp, 8
+    popad
+    popfd
+    add     esp, 4
+    ret
+