Add in the 1st version of ECP.
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@2832 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
qwang12
199
EdkCompatibilityPkg/Foundation/Library/Thunk16/Ia32/Thunk16.asm
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199
EdkCompatibilityPkg/Foundation/Library/Thunk16/Ia32/Thunk16.asm
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;*****************************************************************************
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;*
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;* Copyright (c) 2006 - 2007, Intel Corporation
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;* All rights reserved. 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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;* Module Name:
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;*
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;* Thunk.asm
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;*
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;* Abstract:
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;*
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;* Real mode thunk
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;*
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;*****************************************************************************
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.686p
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EXTERNDEF C mCode16Size:DWORD
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CONST SEGMENT FLAT "DATA" READONLY
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mCode16Size DD _TEXT16SIZE
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CONST ENDS
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_DATA SEGMENT FLAT "DATA"
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NullSegSel DQ 0
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_16BitCsSel LABEL QWORD
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DW -1
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DW 0
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DB 0
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DB 9bh
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DB 8fh ; 16-bit segment
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DB 0
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_16BitSsSel LABEL QWORD
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DW -1
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DW 0
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DB 0
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DB 93h
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DB 8fh ; 16-bit segment
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DB 0
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_16Gdtr LABEL FWORD
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DW $ - offset NullSegSel - 1
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DD offset NullSegSel
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_DATA ENDS
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_TEXT SEGMENT FLAT "CODE" PARA
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IA32_REGS STRUC 4t
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_EDI DD ?
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_ESI DD ?
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_EBP DD ?
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_ESP DD ?
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_EBX DD ?
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_EDX DD ?
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_ECX DD ?
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_EAX DD ?
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_DS DW ?
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_ES DW ?
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_FS DW ?
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_GS DW ?
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_EFLAGS DD ?
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_EIP DD ?
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_CS DW ?
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_SS DW ?
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IA32_REGS ENDS
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_STK16 STRUC 1t
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RetEip DD ?
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RetCs DW ?
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ThunkFlags DW ?
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SavedEsp DD ?
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SavedSs DW ?
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SavedGdtr FWORD ?
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SavedCr0 DD ?
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SavedCr4 DD ?
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_STK16 ENDS
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ASSUME ds:_DATA
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__Thunk16 PROC USES ebp ebx esi edi ds es fs gs
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ASSUME esi:PTR IA32_REGS
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mov esi, [esp + 36]
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movzx edx, [esi]._SS
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mov edi, [esi]._ESP
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add edi, - sizeof (_STK16) - sizeof (IA32_REGS)
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push edi ; save stack offset
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imul eax, edx, 16 ; eax <- edx*16
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add edi, eax ; edi <- linear address of 16-bit stack
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push sizeof (IA32_REGS) / 4
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pop ecx
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rep movsd ; copy context to 16-bit stack
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pop ebx ; ebx <- 16-bit stack offset
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mov eax, offset @F ; return offset
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stosd
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mov eax, cs ; return segment
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stosw
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mov eax, [esp + 40] ; THUNK flags
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stosw
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mov eax, esp
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stosd ; save esp
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mov eax, ss ; save ss
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stosw
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sgdt fword ptr [edi] ; save GDTR
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sidt fword ptr [esp + 36] ; save IDTR
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mov esi, cr0
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mov [edi + 6], esi ; save CR0
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and esi, NOT 80000001h ; esi <- CR0 to set
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mov eax, cr4
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mov [edi + 10], eax ; save CR4
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and al, NOT 30h ; clear PAE & PSE
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mov edi, edx ; edi <- 16-bit stack segment
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mov edx, [esp + 44]
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shl edx, 16
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push edx
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pop edx
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mov dx, _16BitSsSel - NullSegSel
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lgdt _16Gdtr ; load 16-bit GDTR
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DB 0eah
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DD offset @16Bit
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DW _16BitCsSel - NullSegSel ; jmp far 8:@16Bit
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@16Bit:
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mov ss, dx
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mov cr0, esi ; disable protected mode
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mov cr4, eax ; disable PAE & PSE
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db 67h, 0FFh, 06Ch, 024h, 0FCh ; jmp dword ptr [esp-4]
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@@:
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mov eax, ss
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shl eax, 4
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add eax, esp ; eax <- address of 16-bit stack
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lss esp, fword ptr (_STK16 ptr [esp + sizeof (IA32_REGS)]).SavedEsp
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lidt fword ptr [esp + 36] ; restore IDTR
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ret
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__Thunk16 ENDP
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_TEXT ENDS
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_TEXT16 SEGMENT USE16 "CODE" PARA
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_Code16Addr PROC C
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_Code16Addr ENDP
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RealMode PROC
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mov ss, di ; set up stack
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mov esp, ebx
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lidt fword ptr cs:[_16Idtr - _Code16Addr]
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popad
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pop ds
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pop es
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pop fs
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pop gs
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add sp, 4 ; skip EFlags
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test (_STK16 ptr [esp + 8]).ThunkFlags, 1
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jz @F
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pushf
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@@:
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push cs
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; push @FarCallRet - _Code16Addr
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DB 68h ; push /iw
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DW @FarCallRet - _Code16Addr
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jz @F
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jmp fword ptr [esp + 6]
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@@:
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jmp fword ptr [esp + 4]
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@FarCallRet:
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pushfd
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push gs
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push fs
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push es
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push ds
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pushad
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cli
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DB 66h
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lgdt (_STK16 ptr [esp + sizeof (IA32_REGS)]).SavedGdtr
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mov eax, (_STK16 ptr [esp + sizeof (IA32_REGS)]).SavedCr4
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mov cr4, eax
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mov eax, (_STK16 ptr [esp + sizeof (IA32_REGS)]).SavedCr0
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mov cr0, eax ; restore CR0
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jmp fword ptr (_STK16 ptr [esp + sizeof (IA32_REGS)]).RetEip
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RealMode ENDP
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_16Idtr FWORD (1 SHL 10) - 1
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_TEXT16END:
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_TEXT16SIZE = _TEXT16END - _Code16Addr
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_TEXT16 ENDS
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END
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