uint32_t edx; /* Saved EDX. */
uint32_t ecx; /* Saved ECX. */
uint32_t eax; /* Saved EAX. */
+ uint16_t gs, :16; /* Saved GS segment register. */
+ uint16_t fs, :16; /* Saved FS segment register. */
uint16_t es, :16; /* Saved ES segment register. */
uint16_t ds, :16; /* Saved DS segment register. */