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MdePkg BaseLib NASM Thunk16: Use NASM local labels

Browse Source 
http://www.nasm.us/doc/nasmdoc3.html#section-3.9

A local label is a label beginning with the period, and it's actual
name is prefixed by the previous non-local label.

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@16022 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
Jordan Justen
2014-09-01 17:23:39 +00:00
committed by jljusten
parent fbb5393cb7
commit a8458d6cb3
2 changed files with 65 additions and 65 deletions
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54
MdePkg/Library/BaseLib/Ia32/Thunk16.nasm
View File

@@ -59,7 +59,7 @@ SECTION .data
; These are global constant to convey information to C code.
;
ASM_PFX(m16Size) DW InternalAsmThunk16 - ASM_PFX(m16Start)
ASM_PFX(mThunk16Attr) DW _ThunkAttr - ASM_PFX(m16Start)
ASM_PFX(mThunk16Attr) DW _BackFromUserCode.ThunkAttr - 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)
@@ -85,8 +85,8 @@ _BackFromUserCode:
push ss
push cs
DB 66h
call @Base ; push eip
@Base:
call .Base ; push eip
.Base:
pushfw ; pushfd actually
cli ; disable interrupts
push gs
@@ -95,19 +95,19 @@ _BackFromUserCode:
push ds
pushaw ; pushad actually
DB 66h, 0bah ; mov edx, imm32
_ThunkAttr: dd 0
.ThunkAttr: dd 0
test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15
jz @1
jz .1
mov eax, 15cd2401h ; mov ax, 2401h & int 15h
cli ; disable interrupts
jnc @2
@1:
jnc .2
.1:
test dl, THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL
jz @2
jz .2
in al, 92h
or al, 2
out 92h, al ; deactivate A20M#
@2:
.2:
xor ax, ax ; xor eax, eax
mov eax, ss ; mov ax, ss
DB 67h
@@ -122,18 +122,18 @@ _ThunkAttr: dd 0
shl ax, 4 ; shl eax, 4
add bp, ax ; add ebp, eax
DB 66h, 0b8h ; mov eax, imm32
SavedCr4: DD 0
.SavedCr4: DD 0
mov cr4, eax
DB 66h
lgdt [cs:edi + (SavedGdt - @Base)]
lgdt [cs:edi + (SavedGdt - .Base)]
DB 66h, 0b8h ; mov eax, imm32
SavedCr0: DD 0
.SavedCr0: DD 0
mov cr0, eax
DB 0b8h ; mov ax, imm16
SavedSs DW 0
.SavedSs DW 0
mov ss, eax
DB 66h, 0bch ; mov esp, imm32
SavedEsp DD 0
.SavedEsp DD 0
DB 66h
retf ; return to protected mode
@@ -162,7 +162,7 @@ _ToUserCode:
mov cr0, eax ; real mode starts at next instruction
; which (per SDM) *must* be a far JMP.
DB 0eah
_RealAddr: DW 0, 0
.RealAddr: DW 0, 0
mov cr4, ebp
mov ss, esi ; set up 16-bit stack segment
@@ -172,12 +172,12 @@ _RealAddr: DW 0, 0
DB 67h
mov ebp, [esp + IA32_REGS.size] ; BackFromUserCode address from stack
; mov cs:[bp + (SavedSs - _BackFromUserCode)], dx
mov [cs:esi + (SavedSs - _BackFromUserCode)], edx
; mov cs:[bp + (_BackFromUserCode.SavedSs - _BackFromUserCode)], dx
mov [cs:esi + (_BackFromUserCode.SavedSs - _BackFromUserCode)], edx
; mov cs:[bp + (SavedEsp - _BackFromUserCode)], ebx
; mov cs:[bp + (_BackFromUserCode.SavedEsp - _BackFromUserCode)], ebx
DB 2eh, 66h, 89h, 9eh
DW SavedEsp - _BackFromUserCode
DW _BackFromUserCode.SavedEsp - _BackFromUserCode
; lidt cs:[bp + (_16Idtr - _BackFromUserCode)]
DB 2eh, 66h, 0fh, 01h, 9eh
@@ -241,28 +241,28 @@ ASM_PFX(InternalAsmThunk16):
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 - ASM_PFX(m16Start))]
lea edx, [eax + (_BackFromUserCode.SavedCr0 - 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, _RealAddr + 4 - _BackFromUserCode
mov [edx + (_RealAddr - SavedCr0)], eax
sgdt [edx + (SavedGdt - SavedCr0)]
add eax, _ToUserCode.RealAddr + 4 - _BackFromUserCode
mov [edx + (_ToUserCode.RealAddr - _BackFromUserCode.SavedCr0)], eax
sgdt [edx + (SavedGdt - _BackFromUserCode.SavedCr0)]
sidt [esp + 36] ; save IDT stack in argument space
mov eax, cr0
mov [edx], eax ; save CR0 in SavedCr0
mov [edx], eax ; save CR0 in _BackFromUserCode.SavedCr0
and eax, 7ffffffeh ; clear PE, PG bits
mov ebp, cr4
mov [edx + (SavedCr4 - SavedCr0)], ebp
mov [edx + (_BackFromUserCode.SavedCr4 - _BackFromUserCode.SavedCr0)], ebp
and ebp, ~30h ; clear PAE, PSE bits
push 10h
pop ecx ; ecx <- selector for data segments
lgdt [edx + (_16Gdtr - SavedCr0)]
lgdt [edx + (_16Gdtr - _BackFromUserCode.SavedCr0)]
pushfd ; Save df/if indeed
call dword far [edx + (_EntryPoint - SavedCr0)]
call dword far [edx + (_EntryPoint - _BackFromUserCode.SavedCr0)]
popfd
lidt [esp + 36] ; restore protected mode IDTR
lea eax, [ebp - IA32_REGS.size] ; eax <- the address of IA32_REGS