🚀 go-pugleaf

After downloading some info from intel (24319201.PDF, manual for system
management) I tried to program using protected mode instead of real mode
(because I need to). But here is my problem...
When I 'switch' to protected mode using MOV CR0,EAX, The system reboots or
crashes. What am I doing wrong? Can somebody please tell me?

I'm using TASM/TLINK version 3.1 and/or 4.1

The assembling and linking process doesn't generate errors, except for 'No
stack warning'. But that shouldn't mind, because I don't use any.
command line:    tasm /zi pmode
                         tlink /z /3 pmode

Here's my ASM file:
-----
        .386p

data    SEGMENT
        gdt     DD      0
                DD      0
                DD      0000FFFFh
                DD      00CF9200h

        gdtr    LABEL   FWORD
                DD      ?
                DW      15
data    ENDS

code    SEGMENT USE16
        ASSUME cs:code,ds:data

Start:  cli
        xor     eax,eax
        xor     ebx,ebx
        mov     ax,data
        mov     ds,ax
        lea     ebx,gdt
        shl     eax,4
        add     eax,ebx
        lea     ebx,gdtr
        mov     DWORD PTR [ebx],eax
        DB      66h
        lgdt    gdtr

        mov     eax,cr0
        or      eax,1
        mov     cr0,eax
        jmp     prot

prot:   mov     ax,08h
        mov     ds,ax
        mov     es,ax

        mov     ax,2001h
        mov     ebx,0b8000h
        mov     ecx,126-32

lusje:  mov     [ebx],ax
        inc     ah
        add     ebx,2
        loop    lusje

        mov     eax,cr0
        xor     eax,1
        mov     cr0,eax
        jmp     real

real:   sti
        mov     ax,4c00h
        int     21h
code    ENDS
        END     Start

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