_REG32_nPC
if (((gr[_REG32_PC] | gr[_REG32_nPC]) & 3) != 0 ||
gr[_REG32_PC] == 0 || gr[_REG32_nPC] == 0)
tf->tf_npc = (uint64_t)gr[_REG32_nPC];
gr[_REG32_nPC] = tf->tf_npc;