MX_IREQ_OFFSET
*(uint8_t *)((char *)ri->ri_hw + MX_IREQ_OFFSET) = 0;
junk = *(uint8_t *)((char *)ri->ri_hw + MX_IREQ_OFFSET);
*(uint8_t *)((char *)ri->ri_hw + MX_IREQ_OFFSET) = 1;
junk = *(uint8_t *)(base + MX_IREQ_OFFSET);
*(uint8_t *)(base + MX_IREQ_OFFSET) = 0;