EmulatorPkg: Replace BSD License with BSD+Patent License

[mirror_edk2.git] / EmulatorPkg / Sec / Ia32 / SwitchRam.S

#------------------------------------------------------------------------------\r
#\r
# Copyright (c) 2007, Intel Corporation. All rights reserved.<BR>\r
# SPDX-License-Identifier: BSD-2-Clause-Patent\r
#\r
# Module Name:\r
#\r
#   Stack.asm\r
#\r
# Abstract:\r
#\r
#   Switch the stack from temporary memory to permenent memory.\r
#\r
#------------------------------------------------------------------------------\r
\r
 .text\r
\r
\r
//------------------------------------------------------------------------------\r
// VOID\r
// EFIAPI\r
// SecSwitchStack (\r
//   UINT32   TemporaryMemoryBase,\r
//   UINT32   PermenentMemoryBase\r
//   )//\r
//------------------------------------------------------------------------------\r
ASM_GLOBAL ASM_PFX(SecSwitchStack)\r
ASM_PFX(SecSwitchStack):\r
#\r
# Save three register: eax, ebx, ecx\r
#\r
    push  %eax\r
    push  %ebx\r
    push  %ecx\r
    push  %edx\r
\r
#\r
# !!CAUTION!! this function address's is pushed into stack after\r
# migration of whole temporary memory, so need save it to permenent\r
# memory at first!\r
#\r
\r
    movl  20(%esp), %ebx            # Save the first parameter\r
    movl  24(%esp), %ecx            # Save the second parameter\r
\r
#\r
# Save this function's return address into permenent memory at first.\r
# Then, Fixup the esp point to permenent memory\r
#\r
\r
    movl  %esp, %eax\r
    subl  %ebx, %eax\r
    addl  %ecx, %eax\r
    movl  (%esp), %edx                 # copy pushed register's value to permenent memory\r
    movl  %edx, (%eax)\r
    movl  4(%esp), %edx\r
    movl  %edx, 4(%eax)\r
    movl  8(%esp), %edx\r
    movl  %edx, 8(%eax)\r
    movl  12(%esp), %edx\r
    movl  %edx, 12(%eax)\r
    movl  16(%esp), %edx\r
    movl  %edx, 16(%eax)\r
    movl  %eax, %esp                   # From now, esp is pointed to permenent memory\r
\r
#\r
# Fixup the ebp point to permenent memory\r
#\r
#ifndef __APPLE__\r
    movl   %ebp, %eax\r
    subl   %ebx, %eax\r
    addl   %ecx, %eax\r
    movl   %eax, %ebp                  # From now, ebp is pointed to permenent memory\r
\r
#\r
# Fixup callee's ebp point for PeiDispatch\r
#\r
    movl   (%ebp), %eax\r
    subl   %ebx, %eax\r
    addl   %ecx, %eax\r
    movl   %eax, (%ebp)                # From now, Temporary's PPI caller's stack is in permenent memory\r
#endif\r
\r
    pop   %edx\r
    pop   %ecx\r
    pop   %ebx\r
    pop   %eax\r
    ret\r
\r