_REG_G6
uc.uc_mcontext.__gregs[_REG_G6] = r->g6;
r[_REG_G6] = tf->tf_global[6];
tf->tf_global[6] = r[_REG_G6];
gr[_REG_G6] = tf->tf_global[6];
tf->tf_global[6] = (uint64_t)gr[_REG_G6];
gr[_REG_G6] = tf->tf_global[6];
tf->tf_global[6] = (uint64_t)gr[_REG_G6];