diff options
Diffstat (limited to 'MdePkg/Library/BaseLib')
| -rw-r--r-- | MdePkg/Library/BaseLib/X64/Thunk16.asm | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/MdePkg/Library/BaseLib/X64/Thunk16.asm b/MdePkg/Library/BaseLib/X64/Thunk16.asm index b77ba68042..642310869b 100644 --- a/MdePkg/Library/BaseLib/X64/Thunk16.asm +++ b/MdePkg/Library/BaseLib/X64/Thunk16.asm @@ -96,18 +96,25 @@ _ThunkAttr DD ? @2:
mov eax, ss
lea bp, [esp + sizeof (IA32_REGS)]
+ ;
+ ; rsi in the following 2 instructions is indeed bp in 16-bit code
+ ;
mov word ptr (IA32_REGS ptr [rsi - sizeof (IA32_REGS)])._ESP, bp
+ DB 66h
mov ebx, (IA32_REGS ptr [rsi - sizeof (IA32_REGS)])._EIP
shl ax, 4 ; shl eax, 4
add bp, ax ; add ebp, eax
mov ax, cs
shl ax, 4
lea ax, [eax + ebx + (@64BitCode - @Base)]
- DB 2eh ; cs:
- mov [rdi + (@64Eip - @Base)], ax
+ DB 66h, 2eh, 89h, 87h ; mov cs:[bx + (@64Eip - @Base)], eax
+ DW @64Eip - @Base
DB 66h, 0b8h ; mov eax, imm32
SavedCr4 DD ?
mov cr4, rax
+ ;
+ ; rdi in the instruction below is indeed bx in 16-bit code
+ ;
DB 66h, 2eh
lgdt fword ptr [rdi + (SavedGdt - @Base)]
DB 66h
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