UnixPkg/Library/UnixBaseLib/X64/SwitchStack.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
   4 # This program and the accompanying materials
   5 # are licensed and made available under the terms and conditions of the BSD License
   6 # which accompanies this distribution.  The full text of the license may be found at
   7 # http://opensource.org/licenses/bsd-license.php.
   8 #
   9 # THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 # WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11 #
  12 # Module Name:
  13 #
  14 #   SwitchStack.S
  15 #
  16 # Abstract:
  17 #
  18 #------------------------------------------------------------------------------
  19
  20
  21 #------------------------------------------------------------------------------
  22 # Routine Description:
  23 #
  24 #   Routine for switching stacks with 2 parameters
  25 #
  26 # Arguments:
  27 #
  28 #   (rcx) EntryPoint    - Entry point with new stack.
  29 #   (rdx) Context1      - Parameter1 for entry point.
  30 #   (r8)  Context2      - Parameter2 for entry point.
  31 #   (r9)  NewStack      - The pointer to new stack.
  32 #
  33 # Returns:
  34 #
  35 #   None
  36 #
  37 #------------------------------------------------------------------------------
  38 ASM_GLOBAL ASM_PFX(InternalSwitchStack)
  39 ASM_PFX(InternalSwitchStack):
  40     movq    %rcx, %rax
  41     movq    %rdx, %rcx
  42     movq    %r8,  %rdx
  43     #
  44     # Reserve space for register parameters (rcx, rdx, r8 & r9) on the stack,
  45     # in case the callee wishes to spill them.
  46     #
  47     lea     -0x20(%r9), %rsp
  48     call    *%rax