RMIXL_PICREG_READ
c0 = RMIXL_PICREG_READ(RMIXL_PIC_IRTENTRYC0(irt));
c1 = RMIXL_PICREG_READ(RMIXL_PIC_IRTENTRYC1(irt));
r = RMIXL_PICREG_READ(RMIXL_PIC_CONTROL);
KASSERT(RMIXL_PICREG_READ(RMIXL_PIC_IRTENTRYC0(irt)) == 0);
KASSERT(RMIXL_PICREG_READ(RMIXL_PIC_IRTENTRYC1(irt)) == 0);