MdePkg BaseLib NASM Thunk16: Remove remaining 'DB' code
Convert remaining 'DB' code to assembly code by: * Move instruction immediate data labels to end of instruction * Use strict keyword to make sure immediate data size is not optimized Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Jordan Justen <jordan.l.justen@intel.com> Reviewed-by: Liming Gao <liming.gao@intel.com> git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16024 6f19259b-4bc3-4df7-8a09-765794883524
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@@ -59,7 +59,7 @@ SECTION .data
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; These are global constant to convey information to C code.
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;
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ASM_PFX(m16Size) DW InternalAsmThunk16 - ASM_PFX(m16Start)
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ASM_PFX(mThunk16Attr) DW _BackFromUserCode.ThunkAttr - ASM_PFX(m16Start)
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ASM_PFX(mThunk16Attr) DW _BackFromUserCode.ThunkAttrEnd - 4 - ASM_PFX(m16Start)
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ASM_PFX(m16Gdt) DW _NullSegDesc - ASM_PFX(m16Start)
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ASM_PFX(m16GdtrBase) DW _16GdtrBase - ASM_PFX(m16Start)
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ASM_PFX(mTransition) DW _EntryPoint - ASM_PFX(m16Start)
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@@ -94,8 +94,8 @@ o32 call dword .Base ; push eip
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push es
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push ds
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pushad
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DB 66h, 0bah ; mov edx, imm32
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.ThunkAttr: dd 0
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mov edx, strict dword 0
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.ThunkAttrEnd:
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test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15
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jz .1
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mov ax, 2401h
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@@ -116,18 +116,18 @@ o32 call dword .Base ; push eip
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mov bx, [bp - IA32_REGS.size + IA32_REGS._EIP]
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shl eax, 4 ; shl eax, 4
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add ebp, eax ; add ebp, eax
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DB 66h, 0b8h ; mov eax, imm32
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.SavedCr4: DD 0
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mov eax, strict dword 0
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.SavedCr4End:
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mov cr4, eax
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o32 lgdt [cs:bx + (SavedGdt - .Base)]
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DB 66h, 0b8h ; mov eax, imm32
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.SavedCr0: DD 0
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mov eax, strict dword 0
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.SavedCr0End:
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mov cr0, eax
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DB 0b8h ; mov ax, imm16
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.SavedSs DW 0
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mov ax, strict word 0
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.SavedSsEnd:
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mov ss, eax
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DB 66h, 0bch ; mov esp, imm32
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.SavedEsp DD 0
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mov esp, strict dword 0
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.SavedEspEnd:
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o32 retf ; return to protected mode
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_EntryPoint:
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@@ -155,15 +155,14 @@ BITS 16
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mov gs, cx
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mov cr0, eax ; real mode starts at next instruction
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; which (per SDM) *must* be a far JMP.
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DB 0eah
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.RealAddr: DW 0, 0
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jmp 0:strict word 0
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.RealAddrEnd:
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mov cr4, ebp
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mov ss, si ; set up 16-bit stack segment
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xchg esp, ebx ; set up 16-bit stack pointer
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mov bp, [esp + IA32_REGS.size]
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mov [cs:bp + (_BackFromUserCode.SavedSs - _BackFromUserCode)], dx
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mov [cs:bp + (_BackFromUserCode.SavedEsp - _BackFromUserCode)], ebx
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mov [cs:bp + (_BackFromUserCode.SavedSsEnd - 2 - _BackFromUserCode)], dx
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mov [cs:bp + (_BackFromUserCode.SavedEspEnd - 4 - _BackFromUserCode)], ebx
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lidt [cs:bp + (_16Idtr - _BackFromUserCode)]
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popad
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@@ -224,28 +223,28 @@ BITS 32
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rep movsd ; copy RegSet
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mov eax, [esp + 40] ; eax <- address of transition code
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mov esi, edx ; esi <- 16-bit stack segment
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lea edx, [eax + (_BackFromUserCode.SavedCr0 - ASM_PFX(m16Start))]
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lea edx, [eax + (_BackFromUserCode.SavedCr0End - ASM_PFX(m16Start))]
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mov ecx, eax
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and ecx, 0fh
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shl eax, 12
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lea ecx, [ecx + (_BackFromUserCode - ASM_PFX(m16Start))]
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mov ax, cx
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stosd ; [edi] <- return address of user code
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add eax, _ToUserCode.RealAddr + 4 - _BackFromUserCode
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mov [edx + (_ToUserCode.RealAddr - _BackFromUserCode.SavedCr0)], eax
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sgdt [edx + (SavedGdt - _BackFromUserCode.SavedCr0)]
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add eax, _ToUserCode.RealAddrEnd - _BackFromUserCode
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mov [edx + (_ToUserCode.RealAddrEnd - 4 - _BackFromUserCode.SavedCr0End)], eax
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sgdt [edx + (SavedGdt - _BackFromUserCode.SavedCr0End)]
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sidt [esp + 36] ; save IDT stack in argument space
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mov eax, cr0
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mov [edx], eax ; save CR0 in _BackFromUserCode.SavedCr0
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mov [edx - 4], eax ; save CR0 in _BackFromUserCode.SavedCr0End - 4
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and eax, 7ffffffeh ; clear PE, PG bits
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mov ebp, cr4
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mov [edx + (_BackFromUserCode.SavedCr4 - _BackFromUserCode.SavedCr0)], ebp
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mov [edx + (_BackFromUserCode.SavedCr4End - 4 - _BackFromUserCode.SavedCr0End)], ebp
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and ebp, ~30h ; clear PAE, PSE bits
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push 10h
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pop ecx ; ecx <- selector for data segments
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lgdt [edx + (_16Gdtr - _BackFromUserCode.SavedCr0)]
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lgdt [edx + (_16Gdtr - _BackFromUserCode.SavedCr0End)]
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pushfd ; Save df/if indeed
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call dword far [edx + (_EntryPoint - _BackFromUserCode.SavedCr0)]
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call dword far [edx + (_EntryPoint - _BackFromUserCode.SavedCr0End)]
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popfd
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lidt [esp + 36] ; restore protected mode IDTR
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lea eax, [ebp - IA32_REGS.size] ; eax <- the address of IA32_REGS
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