; This is the procedure that is first run when starting a V86 thread
; Parameters : esp+4 = page directory to switch to, esp+8 = v86_regs_t pointer
; Algorithm :
; - Switch page directory
; - Create a false IRET structure, with : (first pushed first)
; GS, FS, DS, ES, SS, SP, EFLAGS (with eflags.if and eflags.vm), CS, IP
; - Set general purpose regisers : ax bx cx dx di si
; - Call iret, switch to V86 mode.
[BITS 32]
[GLOBAL v86_run]
v86_run:
mov eax, [esp + 4]
mov cr3, eax
mov eax, [esp + 8]
xor ebx, ebx
mov bx, [eax + 20] ; get GS
push ebx
mov bx, [eax + 18] ; get FS
push ebx
mov bx, [eax + 14] ; get DS
push ebx
mov bx, [eax + 16] ; get ES
push ebx
mov bx, [eax + 22] ; get SS
push ebx
mov bx, [eax + 26] ; get SP
push ebx
pushf
pop ebx
or ebx, 20200h
push ebx
xor ebx, ebx
mov bx, [eax + 12] ; get CS
push ebx
mov bx, [eax + 24] ; get IP
push ebx
mov bx, [eax + 2]
mov cx, [eax + 4]
mov dx, [eax + 6]
mov di, [eax + 8]
mov si, [eax + 10]
mov ax, [eax]
iret
