mirror of https://github.com/acidanthera/audk.git
79 lines
2.4 KiB
ArmAsm
79 lines
2.4 KiB
ArmAsm
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#------------------------------------------------------------------------------
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#
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# Copyright (c) 2013, Intel Corporation. All rights reserved.<BR>
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# This program and the accompanying materials
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# are licensed and made available under the terms and conditions of the BSD License
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# which accompanies this distribution. The full text of the license may be found at
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# http://opensource.org/licenses/bsd-license.php.
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#
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# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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#
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# Abstract:
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#
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# Switch the stack from temporary memory to permenent memory.
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#
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#------------------------------------------------------------------------------
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#------------------------------------------------------------------------------
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# VOID
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# EFIAPI
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# SecSwitchStack (
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# UINT32 TemporaryMemoryBase,
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# UINT32 PermenentMemoryBase
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# )#
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#------------------------------------------------------------------------------
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ASM_GLOBAL ASM_PFX (SecSwitchStack)
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ASM_PFX(SecSwitchStack):
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#
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# Save standard registers so they can be used to change stack
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#
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pushl %eax
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pushl %ebx
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pushl %ecx
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pushl %edx
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#
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# !!CAUTION!! this function address's is pushed into stack after
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# migration of whole temporary memory, so need save it to permenent
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# memory at first!
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#
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movl 20(%esp), %ebx # Save the first parameter
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movl 24(%esp), %ecx # Save the second parameter
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#
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# Save this function's return address into permenent memory at first.
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# Then, Fixup the esp point to permenent memory
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#
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movl %esp, %eax
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subl %ebx, %eax
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addl %ecx, %eax
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movl 0(%esp), %edx # copy pushed register's value to permenent memory
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movl %edx, 0(%eax)
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movl 4(%esp), %edx
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movl %edx, 4(%eax)
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movl 8(%esp), %edx
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movl %edx, 8(%eax)
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movl 12(%esp), %edx
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movl %edx, 12(%eax)
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movl 16(%esp), %edx # Update this function's return address into permenent memory
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movl %edx, 16(%eax)
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movl %eax, %esp # From now, esp is pointed to permenent memory
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#
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# Fixup the ebp point to permenent memory
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#
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movl %ebp, %eax
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subl %ebx, %eax
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addl %ecx, %eax
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movl %eax, %ebp # From now, ebp is pointed to permenent memory
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popl %edx
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popl %ecx
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popl %ebx
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popl %eax
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ret
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