gdt.h

typedef struct {
   uint32_t prev_tss;   // The previous TSS - if we used hardware task switching this would form a linked list.
   uint32_t esp0;       // The stack pointer to load when we change to kernel mode.
   uint32_t ss0;        // The stack segment to load when we change to kernel mode.
   uint32_t esp1;       // everything below here is unusued now.. 
   uint32_t ss1;
   uint32_t esp2;
   uint32_t ss2;
   uint32_t cr3;
   uint32_t eip;
   uint32_t eflags;
   uint32_t eax;
   uint32_t ecx;
   uint32_t edx;
   uint32_t ebx;
   uint32_t esp;
   uint32_t ebp;
   uint32_t esi;
   uint32_t edi;
   uint32_t es;         
   uint32_t cs;        
   uint32_t ss;        
   uint32_t ds;        
   uint32_t fs;       
   uint32_t gs;         
   uint32_t ldt;      
   uint16_t trap;
   uint16_t iomap_base;
} tss_struct_t;

extern tss_struct_t tss_table;