TSS
struct tss { uint32_t reserved0; uint64_t rsp0; uint64_t rsp1; uint64_t rsp2; uint64_t reserved1; uint64_t ist1; uint64_t ist2; uint64_t ist3; uint64_t ist4; uint64_t ist5; uint64_t ist6; uint64_t ist7; uint64_t reserved2; uint16_t reserved3; uint16_t io_map_base;};