diff options
Diffstat (limited to 'MdePkg/Library/BaseLib/Ia32/Thunk16.nasm')
-rw-r--r-- | MdePkg/Library/BaseLib/Ia32/Thunk16.nasm | 263 |
1 files changed, 0 insertions, 263 deletions
diff --git a/MdePkg/Library/BaseLib/Ia32/Thunk16.nasm b/MdePkg/Library/BaseLib/Ia32/Thunk16.nasm deleted file mode 100644 index 794d83159a..0000000000 --- a/MdePkg/Library/BaseLib/Ia32/Thunk16.nasm +++ /dev/null @@ -1,263 +0,0 @@ -
-#include "BaseLibInternals.h"
-
-;------------------------------------------------------------------------------
-;
-; Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
-; This program and the accompanying materials
-; are licensed and made available under the terms and conditions of the BSD License
-; which accompanies this distribution. The full text of the license may be found at
-; http://opensource.org/licenses/bsd-license.php.
-;
-; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
-; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
-;
-; Module Name:
-;
-; Thunk.asm
-;
-; Abstract:
-;
-; Real mode thunk
-;
-;------------------------------------------------------------------------------
-
-global ASM_PFX(m16Size)
-global ASM_PFX(mThunk16Attr)
-global ASM_PFX(m16Gdt)
-global ASM_PFX(m16GdtrBase)
-global ASM_PFX(mTransition)
-global ASM_PFX(m16Start)
-
-struc IA32_REGS
-
- ._EDI: resd 1
- ._ESI: resd 1
- ._EBP: resd 1
- ._ESP: resd 1
- ._EBX: resd 1
- ._EDX: resd 1
- ._ECX: resd 1
- ._EAX: resd 1
- ._DS: resw 1
- ._ES: resw 1
- ._FS: resw 1
- ._GS: resw 1
- ._EFLAGS: resd 1
- ._EIP: resd 1
- ._CS: resw 1
- ._SS: resw 1
- .size:
-
-endstruc
-
-;; .const
-
-SECTION .data
-
-;
-; These are global constant to convey information to C code.
-;
-ASM_PFX(m16Size) DW ASM_PFX(InternalAsmThunk16) - ASM_PFX(m16Start)
-ASM_PFX(mThunk16Attr) DW _BackFromUserCode.ThunkAttrEnd - 4 - ASM_PFX(m16Start)
-ASM_PFX(m16Gdt) DW _NullSegDesc - ASM_PFX(m16Start)
-ASM_PFX(m16GdtrBase) DW _16GdtrBase - ASM_PFX(m16Start)
-ASM_PFX(mTransition) DW _EntryPoint - ASM_PFX(m16Start)
-
-SECTION .text
-
-ASM_PFX(m16Start):
-
-SavedGdt:
- dw 0
- dd 0
-
-;------------------------------------------------------------------------------
-; _BackFromUserCode() takes control in real mode after 'retf' has been executed
-; by user code. It will be shadowed to somewhere in memory below 1MB.
-;------------------------------------------------------------------------------
-_BackFromUserCode:
- ;
- ; The order of saved registers on the stack matches the order they appears
- ; in IA32_REGS structure. This facilitates wrapper function to extract them
- ; into that structure.
- ;
-BITS 16
- push ss
- push cs
- ;
- ; Note: We can't use o32 on the next instruction because of a bug
- ; in NASM 2.09.04 through 2.10rc1.
- ;
- call dword .Base ; push eip
-.Base:
- pushfd
- cli ; disable interrupts
- push gs
- push fs
- push es
- push ds
- pushad
- mov edx, strict dword 0
-.ThunkAttrEnd:
- test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15
- jz .1
- mov ax, 2401h
- int 15h
- cli ; disable interrupts
- jnc .2
-.1:
- test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL
- jz .2
- in al, 92h
- or al, 2
- out 92h, al ; deactivate A20M#
-.2:
- xor eax, eax
- mov ax, ss
- lea ebp, [esp + IA32_REGS.size]
- mov [bp - IA32_REGS.size + IA32_REGS._ESP], ebp
- mov bx, [bp - IA32_REGS.size + IA32_REGS._EIP]
- shl eax, 4 ; shl eax, 4
- add ebp, eax ; add ebp, eax
- mov eax, strict dword 0
-.SavedCr4End:
- mov cr4, eax
-o32 lgdt [cs:bx + (SavedGdt - .Base)]
- mov eax, strict dword 0
-.SavedCr0End:
- mov cr0, eax
- mov ax, strict word 0
-.SavedSsEnd:
- mov ss, eax
- mov esp, strict dword 0
-.SavedEspEnd:
-o32 retf ; return to protected mode
-
-_EntryPoint:
- DD _ToUserCode - ASM_PFX(m16Start)
- DW 8h
-_16Idtr:
- DW (1 << 10) - 1
- DD 0
-_16Gdtr:
- DW GdtEnd - _NullSegDesc - 1
-_16GdtrBase:
- DD 0
-
-;------------------------------------------------------------------------------
-; _ToUserCode() takes control in real mode before passing control to user code.
-; It will be shadowed to somewhere in memory below 1MB.
-;------------------------------------------------------------------------------
-_ToUserCode:
-BITS 16
- mov dx, ss
- mov ss, cx ; set new segment selectors
- mov ds, cx
- mov es, cx
- mov fs, cx
- mov gs, cx
- mov cr0, eax ; real mode starts at next instruction
- ; which (per SDM) *must* be a far JMP.
- jmp 0:strict word 0
-.RealAddrEnd:
- mov cr4, ebp
- mov ss, si ; set up 16-bit stack segment
- xchg esp, ebx ; set up 16-bit stack pointer
- mov bp, [esp + IA32_REGS.size]
- mov [cs:bp + (_BackFromUserCode.SavedSsEnd - 2 - _BackFromUserCode)], dx
- mov [cs:bp + (_BackFromUserCode.SavedEspEnd - 4 - _BackFromUserCode)], ebx
- lidt [cs:bp + (_16Idtr - _BackFromUserCode)]
-
- popad
- pop ds
- pop es
- pop fs
- pop gs
- popfd
-
-o32 retf ; transfer control to user code
-
-ALIGN 16
-_NullSegDesc DQ 0
-_16CsDesc:
- DW -1
- DW 0
- DB 0
- DB 9bh
- DB 8fh ; 16-bit segment, 4GB limit
- DB 0
-_16DsDesc:
- DW -1
- DW 0
- DB 0
- DB 93h
- DB 8fh ; 16-bit segment, 4GB limit
- DB 0
-GdtEnd:
-
-;------------------------------------------------------------------------------
-; IA32_REGISTER_SET *
-; EFIAPI
-; InternalAsmThunk16 (
-; IN IA32_REGISTER_SET *RegisterSet,
-; IN OUT VOID *Transition
-; );
-;------------------------------------------------------------------------------
-global ASM_PFX(InternalAsmThunk16)
-ASM_PFX(InternalAsmThunk16):
-BITS 32
- push ebp
- push ebx
- push esi
- push edi
- push ds
- push es
- push fs
- push gs
- mov esi, [esp + 36] ; esi <- RegSet, the 1st parameter
- movzx edx, word [esi + IA32_REGS._SS]
- mov edi, [esi + IA32_REGS._ESP]
- add edi, - (IA32_REGS.size + 4) ; reserve stack space
- mov ebx, edi ; ebx <- stack offset
- imul eax, edx, 16 ; eax <- edx * 16
- push IA32_REGS.size / 4
- add edi, eax ; edi <- linear address of 16-bit stack
- pop ecx
- rep movsd ; copy RegSet
- mov eax, [esp + 40] ; eax <- address of transition code
- mov esi, edx ; esi <- 16-bit stack segment
- lea edx, [eax + (_BackFromUserCode.SavedCr0End - ASM_PFX(m16Start))]
- mov ecx, eax
- and ecx, 0fh
- shl eax, 12
- lea ecx, [ecx + (_BackFromUserCode - ASM_PFX(m16Start))]
- mov ax, cx
- stosd ; [edi] <- return address of user code
- add eax, _ToUserCode.RealAddrEnd - _BackFromUserCode
- mov [edx + (_ToUserCode.RealAddrEnd - 4 - _BackFromUserCode.SavedCr0End)], eax
- sgdt [edx + (SavedGdt - _BackFromUserCode.SavedCr0End)]
- sidt [esp + 36] ; save IDT stack in argument space
- mov eax, cr0
- mov [edx - 4], eax ; save CR0 in _BackFromUserCode.SavedCr0End - 4
- and eax, 7ffffffeh ; clear PE, PG bits
- mov ebp, cr4
- mov [edx + (_BackFromUserCode.SavedCr4End - 4 - _BackFromUserCode.SavedCr0End)], ebp
- and ebp, ~30h ; clear PAE, PSE bits
- push 10h
- pop ecx ; ecx <- selector for data segments
- lgdt [edx + (_16Gdtr - _BackFromUserCode.SavedCr0End)]
- pushfd ; Save df/if indeed
- call dword far [edx + (_EntryPoint - _BackFromUserCode.SavedCr0End)]
- popfd
- lidt [esp + 36] ; restore protected mode IDTR
- lea eax, [ebp - IA32_REGS.size] ; eax <- the address of IA32_REGS
- pop gs
- pop fs
- pop es
- pop ds
- pop edi
- pop esi
- pop ebx
- pop ebp
- ret
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