M_RXFIFOPAUSEHWM
#define G_RXFIFOPAUSEHWM(x) (((x) >> S_RXFIFOPAUSEHWM) & M_RXFIFOPAUSEHWM)
v = (v & ~V_RXFIFOPAUSEHWM(M_RXFIFOPAUSEHWM)) |
val &= ~V_RXFIFOPAUSEHWM(M_RXFIFOPAUSEHWM);