// https://xarnze.com/posts/post/Tutorial:%20Entering%20User%20mode
// http://wiki.osdev.org/TSS
// http://wiki.osdev.org/Global_Descriptor_Table

typedef volatile struct strtss{
    unsigned short   link;
    unsigned short   link_h;  
    unsigned long   esp0;
    unsigned short   ss0;
    unsigned short   ss0_h;  
    unsigned long   esp1;
    unsigned short   ss1;
    unsigned short   ss1_h;  
    unsigned long   esp2;
    unsigned short   ss2;
    unsigned short   ss2_h;  
    unsigned long   cr3;
    unsigned long   eip;
    unsigned long   eflags;  
    unsigned long   eax;
    unsigned long   ecx; 
    unsigned long   edx;
    unsigned long    ebx;  
    unsigned long   esp;
    unsigned long   ebp;  
    unsigned long   esi;
    unsigned long   edi;  
    unsigned short   es;
    unsigned short   es_h;  
    unsigned short   cs;
    unsigned short   cs_h;  
    unsigned short   ss;
    unsigned short   ss_h;  
    unsigned short   ds;
    unsigned short   ds_h;  
    unsigned short   fs;
    unsigned short   fs_h;  
    unsigned short   gs;
    unsigned short   gs_h;  
    unsigned short   ldt;
    unsigned short   ldt_h;  
    unsigned short   trap;
    unsigned short   iomap;  
}__attribute__((packed)) tss_struct;  

tss_struct sys_tss; //Define the TSS as a global structure