i386_set_threadbase
error = i386_set_threadbase(p, base, TSEG_FS);
error = i386_set_threadbase(p, base, TSEG_GS);
i386_set_threadbase(p2, (uint32_t)tcb, TSEG_GS);
int i386_set_threadbase(struct proc *, uint32_t, int);
i386_set_threadbase(p, (uint32_t)(addr), TSEG_GS)