set_sys_segment
set_sys_segment(&d.sd, base, limit, type, dpl, gran);
set_sys_segment(GDT_ADDR_SYS(gdtstore, GLDT_SEL), ldtstore,
set_sys_segment(GDT_ADDR_SYS(gdtstore, GLDT_SEL), ldtstore,
void set_sys_segment(struct sys_segment_descriptor *, void *, size_t,