PORT_HDR_STS
v = readq(base_hdr + PORT_HDR_STS);
v = readq(base + PORT_HDR_STS);
writeq(PORT_STS_AP1_EVT, base + PORT_HDR_STS);
v = readq(base + PORT_HDR_STS);
writeq(PORT_STS_AP2_EVT, base + PORT_HDR_STS);
v = readq(base + PORT_HDR_STS);