X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=blobdiff_plain;f=OldMdePkg%2FLibrary%2FBaseLib%2FIa32%2FThunk16.asm;fp=OldMdePkg%2FLibrary%2FBaseLib%2FIa32%2FThunk16.asm;h=0000000000000000000000000000000000000000;hp=5c9bc81a2bc3e6a1a624bddf7b65e1829a73846a;hb=808def96aa4589fba9c2d0ea55837754a3b7a4f7;hpb=9216450d1143056a50a5f916984a2d7faf590488 diff --git a/OldMdePkg/Library/BaseLib/Ia32/Thunk16.asm b/OldMdePkg/Library/BaseLib/Ia32/Thunk16.asm deleted file mode 100644 index 5c9bc81a2b..0000000000 --- a/OldMdePkg/Library/BaseLib/Ia32/Thunk16.asm +++ /dev/null @@ -1,248 +0,0 @@ -;------------------------------------------------------------------------------ -; -; Copyright (c) 2006, Intel Corporation -; All rights reserved. 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 -; -;------------------------------------------------------------------------------ - - .686p - .model flat,C - -EXTERNDEF C m16Start:BYTE -EXTERNDEF C m16Size:WORD -EXTERNDEF C mThunk16Attr:WORD -EXTERNDEF C m16Gdt:WORD -EXTERNDEF C m16GdtrBase:WORD -EXTERNDEF C mTransition:WORD - -; -; Here is the layout of the real mode stack. _ToUserCode() is responsible for -; loading all these registers from real mode stack. -; -IA32_REGS STRUC 4t -_EDI DD ? -_ESI DD ? -_EBP DD ? -_ESP DD ? -_EBX DD ? -_EDX DD ? -_ECX DD ? -_EAX DD ? -_DS DW ? -_ES DW ? -_FS DW ? -_GS DW ? -_EFLAGS DD ? -_EIP DD ? -_CS DW ? -_SS DW ? -IA32_REGS ENDS - - .const - -; -; These are global constant to convey information to C code. -; -m16Size DW InternalAsmThunk16 - m16Start -mThunk16Attr DW _ThunkAttr - m16Start -m16Gdt DW _NullSegDesc - m16Start -m16GdtrBase DW _16GdtrBase - m16Start -mTransition DW _EntryPoint - m16Start - - .code - -m16Start LABEL BYTE - -SavedGdt LABEL FWORD - DW ? - DD ? -;------------------------------------------------------------------------------ -; _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 PROC - ; - ; 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. - ; - push ss - push cs - DB 66h - call @Base ; push eip -@Base: - pushf ; pushfd actually - cli ; disable interrupts - push gs - push fs - push es - push ds - pushaw ; pushad actually - DB 66h, 0bah ; mov edx, imm32 -_ThunkAttr DD ? - test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15 - jz @1 - mov eax, 15cd2401h ; 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: - mov eax, ss - DB 67h - lea bp, [esp + sizeof (IA32_REGS)] - ; - ; esi's in the following 2 instructions are indeed bp in 16-bit code. Fact - ; is "esi" in 32-bit addressing mode has the same encoding of "bp" in 16- - ; bit addressing mode. - ; - mov word ptr (IA32_REGS ptr [esi - sizeof (IA32_REGS)])._ESP, bp - mov ebx, (IA32_REGS ptr [esi - sizeof (IA32_REGS)])._EIP - shl ax, 4 ; shl eax, 4 - add bp, ax ; add ebp, eax - DB 66h, 0b8h ; mov eax, imm32 -SavedCr4 DD ? - mov cr4, eax - DB 66h - lgdt fword ptr cs:[edi + (SavedGdt - @Base)] - DB 66h, 0b8h ; mov eax, imm32 -SavedCr0 DD ? - mov cr0, eax - DB 0b8h ; mov ax, imm16 -SavedSs DW ? - mov ss, eax - DB 66h, 0bch ; mov esp, imm32 -SavedEsp DD ? - DB 66h - retf ; return to protected mode -_BackFromUserCode ENDP - -_EntryPoint DD _ToUserCode - m16Start - DW 8h -_16Idtr FWORD (1 SHL 10) - 1 -_16Gdtr LABEL FWORD - DW GdtEnd - _NullSegDesc - 1 -_16GdtrBase DD _NullSegDesc - -;------------------------------------------------------------------------------ -; _ToUserCode() takes control in real mode before passing control to user code. -; It will be shadowed to somewhere in memory below 1MB. -;------------------------------------------------------------------------------ -_ToUserCode PROC - mov edx, ss - mov ss, ecx ; set new segment selectors - mov ds, ecx - mov es, ecx - mov fs, ecx - mov gs, ecx - mov cr0, eax - mov cr4, ebp ; real mode starts at next instruction - mov ss, esi ; set up 16-bit stack segment - xchg sp, bx ; set up 16-bit stack pointer - DB 66h - call @Base ; push eip -@Base: - pop bp ; ebp <- address of @Base - DB 67h ; address size override - push [esp + sizeof (IA32_REGS) + 2] - lea eax, [esi + (@RealMode - @Base)] - push eax - retf -@RealMode: - mov cs:[esi + (SavedSs - @Base)], edx - mov cs:[esi + (SavedEsp - @Base)], bx - DB 66h - lidt fword ptr cs:[esi + (_16Idtr - @Base)] - popaw ; popad actually - pop ds - pop es - pop fs - pop gs - popf ; popfd - DB 66h ; Use 32-bit addressing for "retf" below - retf ; transfer control to user code -_ToUserCode ENDP - -_NullSegDesc DQ 0 -_16CsDesc LABEL QWORD - DW -1 - DW 0 - DB 0 - DB 9bh - DB 8fh ; 16-bit segment, 4GB limit - DB 0 -_16DsDesc LABEL QWORD - DW -1 - DW 0 - DB 0 - DB 93h - DB 8fh ; 16-bit segment, 4GB limit - DB 0 -GdtEnd LABEL QWORD - -;------------------------------------------------------------------------------ -; IA32_REGISTER_SET * -; EFIAPI -; InternalAsmThunk16 ( -; IN IA32_REGISTER_SET *RegisterSet, -; IN OUT VOID *Transition -; ); -;------------------------------------------------------------------------------ -InternalAsmThunk16 PROC USES ebp ebx esi edi ds es fs gs - mov esi, [esp + 36] ; esi <- RegSet, the 1st parameter - movzx edx, (IA32_REGS ptr [esi])._SS - mov edi, (IA32_REGS ptr [esi])._ESP - add edi, - (sizeof (IA32_REGS) + 4) ; reserve stack space - mov ebx, edi ; ebx <- stack offset - imul eax, edx, 16 ; eax <- edx * 16 - push sizeof (IA32_REGS) / 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 + (SavedCr0 - m16Start)] - mov ecx, eax - and ecx, 0fh - shl eax, 12 - lea ecx, [ecx + (_BackFromUserCode - m16Start)] - mov ax, cx - stosd ; [edi] <- return address of user code - sgdt fword ptr [edx + (SavedGdt - SavedCr0)] - sidt fword ptr [esp + 36] ; save IDT stack in argument space - mov eax, cr0 - mov [edx], eax ; save CR0 in SavedCr0 - and eax, 7ffffffeh ; clear PE, PG bits - mov ebp, cr4 - mov [edx + (SavedCr4 - SavedCr0)], ebp - and ebp, 300h ; clear all but PCE and OSFXSR bits - push 10h - pop ecx ; ecx <- selector for data segments - lgdt fword ptr [edx + (_16Gdtr - SavedCr0)] - pushfd ; Save df/if indeed - call fword ptr [edx + (_EntryPoint - SavedCr0)] - popfd - lidt fword ptr [esp + 36] ; restore protected mode IDTR - lea eax, [ebp - sizeof (IA32_REGS)] ; eax <- the address of IA32_REGS - ret -InternalAsmThunk16 ENDP - - END