MdePkg/Library/BaseLib/X64/SwitchStack.nasm

;------------------------------------------------------------------------------
;
; Copyright (c) 2006 - 2008, 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.
;
; Module Name:
;
;   SwitchStack.Asm
;
; Abstract:
;
;------------------------------------------------------------------------------

    DEFAULT REL
    SECTION .text

;------------------------------------------------------------------------------
; Routine Description:
;
;   Routine for switching stacks with 2 parameters
;
; Arguments:
;
;   (rcx) EntryPoint    - Entry point with new stack.
;   (rdx) Context1      - Parameter1 for entry point.
;   (r8)  Context2      - Parameter2 for entry point.
;   (r9)  NewStack      - The pointer to new stack.
;
; Returns:
;
;   None
;
;------------------------------------------------------------------------------
global ASM_PFX(InternalSwitchStack)
ASM_PFX(InternalSwitchStack):
    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 - 0x20]
    call    rax