EmulatorPkg/Unix/Host/X64/SwitchStack.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
   4 # Portitions copyright (c) 2011, Apple Inc. All rights reserved.
   5 # SPDX-License-Identifier: BSD-2-Clause-Patent
   6 #
   7 #------------------------------------------------------------------------------
   8
   9
  10 #------------------------------------------------------------------------------
  11 # Routine Description:
  12 #
  13 #   Routine for switching stacks with 2 parameters EFI ABI
  14 #   Convert UNIX to EFI ABI
  15 #
  16 # Arguments:
  17 #
  18 #   (rdi) EntryPoint    - Entry point with new stack.
  19 #   (rsi) Context1      - Parameter1 for entry point. (rcx)
  20 #   (rdx) Context2      - Parameter2 for entry point. (rdx)
  21 #   (rcx) NewStack      - The pointer to new stack.
  22 #
  23 # Returns:
  24 #
  25 #   None
  26 #
  27 #------------------------------------------------------------------------------
  28 ASM_GLOBAL ASM_PFX(PeiSwitchStacks)
  29 ASM_PFX(PeiSwitchStacks):
  30     pushq   $0            // tells gdb to stop unwinding frame
  31     movq    %rsp, %rbp
  32
  33     movq    %rcx, %rsp    // update stack pointer
  34
  35     movq    %rdi, %rax    // entry point to %rax
  36     movq    %rsi, %rcx    // Adjust Context1
  37                           // Context2 already in the rigth spot
  38
  39     #
  40     # Reserve space for register parameters (rcx, rdx, r8 & r9) on the stack,
  41     # in case the callee wishes to spill them.
  42     #
  43     subq    $32, %rsp  // 32-byte shadow space plus alignment pad
  44     call    *%rax
  45
  46
  47