EXTERNDEF C m16GdtrBase:WORD\r
EXTERNDEF C mTransition:WORD\r
\r
-;THUNK_ATTRIBUTE_BIG_REAL_MODE EQU 1\r
-;THUNK_ATTRIBUTE_DISABLE_A20_MASK_INT_15 EQU 2\r
-;THUNK_ATTRIBUTE_DISABLE_A20_MASK_KBD_CTRL EQU 4\r
-\r
IA32_REGS STRUC 4t\r
_EDI DD ?\r
_ESI DD ?\r
\r
.const\r
\r
-m16Size DW offset InternalAsmThunk16 - offset m16Start\r
-mThunk16Attr DW offset _ThunkAttr - offset m16Start\r
-m16Gdt DW offset _NullSegDesc - offset m16Start\r
-m16GdtrBase DW offset _16GdtrBase - offset m16Start\r
-mTransition DW offset _EntryPoint - offset m16Start\r
+m16Size DW InternalAsmThunk16 - m16Start\r
+mThunk16Attr DW _ThunkAttr - m16Start\r
+m16Gdt DW _NullSegDesc - m16Start\r
+m16GdtrBase DW _16GdtrBase - m16Start\r
+mTransition DW _EntryPoint - m16Start\r
\r
.code\r
\r
m16Start LABEL BYTE\r
\r
-SavedGdt LABEL FWORD\r
- DW ?\r
- DD ?\r
+SavedGdt LABEL FWORD\r
+ DW ?\r
+ DD ?\r
\r
_BackFromUserCode PROC\r
push ss\r
SavedCr4 DD ?\r
mov cr4, eax\r
DB 66h\r
- lgdt fword ptr cs:[edi + (offset SavedGdt - offset @Base)]\r
+ lgdt fword ptr cs:[edi + (SavedGdt - @Base)]\r
DB 66h, 0b8h ; mov eax, imm32\r
SavedCr0 DD ?\r
mov cr0, eax\r
retf ; return to protected mode\r
_BackFromUserCode ENDP\r
\r
-_EntryPoint DD offset _ToUserCode - offset m16Start\r
- DW 8h\r
-_16Idtr FWORD (1 SHL 10) - 1\r
-_16Gdtr LABEL FWORD\r
- DW offset GdtEnd - offset _NullSegDesc - 1\r
-_16GdtrBase DD offset _NullSegDesc\r
+_EntryPoint DD _ToUserCode - m16Start\r
+ DW 8h\r
+_16Idtr FWORD (1 SHL 10) - 1\r
+_16Gdtr LABEL FWORD\r
+ DW GdtEnd - _NullSegDesc - 1\r
+_16GdtrBase DD _NullSegDesc\r
\r
_ToUserCode PROC\r
mov edx, ss\r
DB 66h\r
call @Base ; push eip\r
@Base:\r
- pop bp ; ebp <- offset @Base\r
+ pop bp ; ebp <- address of @Base\r
DB 67h ; address size override\r
push [esp + sizeof (IA32_REGS) + 2]\r
- lea eax, [esi + (offset @RealMode - offset @Base)]\r
+ lea eax, [esi + (@RealMode - @Base)]\r
push eax\r
retf\r
@RealMode:\r
- mov cs:[esi + (offset SavedSs - offset @Base)], edx\r
- mov cs:[esi + (offset SavedEsp - offset @Base)], bx\r
+ mov cs:[esi + (SavedSs - @Base)], edx\r
+ mov cs:[esi + (SavedEsp - @Base)], bx\r
DB 66h\r
- lidt fword ptr cs:[esi + (offset _16Idtr - offset @Base)]\r
+ lidt fword ptr cs:[esi + (_16Idtr - @Base)]\r
popaw ; popad actually\r
pop ds\r
pop es\r
rep movsd ; copy RegSet\r
mov eax, [esp + 40] ; eax <- address of transition code\r
mov esi, edx ; esi <- 16-bit stack segment\r
- lea edx, [eax + (offset SavedCr0 - offset m16Start)]\r
+ lea edx, [eax + (SavedCr0 - m16Start)]\r
mov ecx, eax\r
and ecx, 0fh\r
shl eax, 12\r
- lea ecx, [ecx + (offset _BackFromUserCode - offset m16Start)]\r
+ lea ecx, [ecx + (_BackFromUserCode - m16Start)]\r
mov ax, cx\r
stosd ; [edi] <- return address of user code\r
- sgdt fword ptr [edx + (offset SavedGdt - offset SavedCr0)]\r
+ sgdt fword ptr [edx + (SavedGdt - SavedCr0)]\r
sidt fword ptr [esp + 36] ; save IDT stack in argument space\r
mov eax, cr0\r
mov [edx], eax ; save CR0 in SavedCr0\r
and eax, 7ffffffeh ; clear PE, PG bits\r
mov ebp, cr4\r
- mov [edx + (offset SavedCr4 - offset SavedCr0)], ebp\r
+ mov [edx + (SavedCr4 - SavedCr0)], ebp\r
and ebp, 300h ; clear all but PCE and OSFXSR bits\r
push 10h\r
pop ecx ; ecx <- selector for data segments\r
- lgdt fword ptr [edx + (offset _16Gdtr - offset SavedCr0)]\r
+ lgdt fword ptr [edx + (_16Gdtr - SavedCr0)]\r
pushfd\r
- call fword ptr [edx + (offset _EntryPoint - offset SavedCr0)]\r
+ call fword ptr [edx + (_EntryPoint - SavedCr0)]\r
popfd\r
lidt fword ptr [esp + 36] ; restore protected mode IDTR\r
lea eax, [ebp - sizeof (IA32_REGS)]\r