REG_INT_STAT
if (GET16(ss, REG_INT_STAT) & INT_CMD) {
PUT16(ss, REG_INT_STAT, INT_CMD);
intr = GET16(ss, REG_INT_STAT);
PUT16(ss, REG_INT_STAT, intr);
PUT16(ss, REG_INT_STAT, INT_DMA);
PUT16(ss, REG_INT_STAT, INT_RD);
PUT16(ss, REG_INT_STAT, INT_WR);
PUT16(ss, REG_INT_STAT, INT_XFR);
PUT16(ss, REG_INT_STAT, INT_ERR);