GS_S_CSR_REG
_reg_write_8(GS_S_CSR_REG, 1 << 9);
_reg_write_8(GS_S_CSR_REG, 1 << 8);
while ((_reg_read_8(GS_S_CSR_REG) & (3 << 14)) != (1 << 14))