_REG_TP
u->uc_mcontext.__gregs[_REG_TP] =
u->uc_mcontext.__gregs[_REG_TP] =
const __greg_t saved_tp = tf->tf_reg[_REG_TP];
tf->tf_reg[_REG_TP] = saved_tp;
tf->tf_reg[_REG_TP] = (register_t)addr;