1. Add comments about reserve space on space according to x64 calling convention

2. Fix comments in SwitchStack as for the x64 calling convention.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@5315 6f19259b-4bc3-4df7-8a09-765794883524

2 files changed, 17 insertions, 9 deletions

diff --git a/MdePkg/Library/BaseLib/X64/SwitchStack.S b/MdePkg/Library/BaseLib/X64/SwitchStack.S
index 85cdb4306d..9aee37b0e9 100644
--- a/MdePkg/Library/BaseLib/X64/SwitchStack.S
+++ b/MdePkg/Library/BaseLib/X64/SwitchStack.S
@@ -1,6 +1,6 @@
 #------------------------------------------------------------------------------
 #
-# Copyright (c) 2006, Intel Corporation
+# Copyright (c) 2006 - 2008, 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
@@ -21,14 +21,14 @@
 #------------------------------------------------------------------------------
 # Routine Description:
 #
-#   Routine for switching stacks with 1 parameter
+#   Routine for switching stacks with 2 parameters
 #
 # Arguments:
 #
-#   (rdi) EntryPoint    - Entry point with new stack.
-#   (rsi) Context1      - Parameter1 for entry point.
-#   (rdx)  Context2     - Parameter2 for entry point.
-#   (rcx)  NewStack     - Pointer to new stack.
+#   (rcx) EntryPoint    - Entry point with new stack.
+#   (rdx) Context1      - Parameter1 for entry point.
+#   (r8)  Context2      - Parameter2 for entry point.
+#   (r9)  NewStack      - Pointer to new stack.
 #
 # Returns:
 #
@@ -40,5 +40,9 @@ _InternalSwitchStack:
     mov     %rcx, %rax
     mov     %rdx, %rcx
     mov     %r8, %rdx
+    #

+    # Reserve space for register parameters (rcx, rdx, r8 & r9) on the stack,

+    # in case the callee wishes to spill them.

+    #
     lea     -0x20(%r9), %rsp
     call    *%rax
diff --git a/MdePkg/Library/BaseLib/X64/SwitchStack.asm b/MdePkg/Library/BaseLib/X64/SwitchStack.asm
index 53d1417f0b..380289a2d0 100644
--- a/MdePkg/Library/BaseLib/X64/SwitchStack.asm
+++ b/MdePkg/Library/BaseLib/X64/SwitchStack.asm
@@ -1,6 +1,6 @@
 ;------------------------------------------------------------------------------

 ;

-; Copyright (c) 2006, Intel Corporation

+; Copyright (c) 2006 - 2008, 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

@@ -22,12 +22,12 @@
 ;------------------------------------------------------------------------------

 ; Routine Description:

 ;

-;   Routine for switching stacks with 1 parameter

+;   Routine for switching stacks with 2 parameters

 ;

 ; Arguments:

 ;

 ;   (rcx) EntryPoint    - Entry point with new stack.

-;   (rdx) Context       - Parameter for entry point.

+;   (rdx) Context1      - Parameter1 for entry point.

 ;   (r8)  Context2      - Parameter2 for entry point.

 ;   (r9)  NewStack      - Pointer to new stack.

 ;

@@ -40,6 +40,10 @@ InternalSwitchStack PROC
     mov     rax, rcx

     mov     rcx, rdx

     mov     rdx, r8

+    ;

+    ; Reserve space for register parameters (rcx, rdx, r8 & r9) on the stack,

+    ; in case the callee wishes to spill them.

+    ;

     lea     rsp, [r9 - 20h]

     call    rax

 InternalSwitchStack ENDP