MdePkg/Library/BaseLib/X64/SwitchStack.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2006 - 2018, 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     pushq   %rbp
  41     movq    %rsp, %rbp
  42
  43     mov     %rcx, %rax  // Shift registers for new call
  44     mov     %rdx, %rcx
  45     mov     %r8, %rdx
  46     #
  47     # Reserve space for register parameters (rcx, rdx, r8 & r9) on the stack,
  48     # in case the callee wishes to spill them.
  49     #
  50     lea     -0x20(%r9), %rsp
  51     pushq   $0        // stop gdb stack unwind
  52     jmp     *%rax     // call EntryPoint ()