> This is not the direct `memory map' of the IDE drive's registers! It's an > indirect map, cfr. e.g. > > #define IDE_DATA_REG (HWIF(drive)->io_ports[IDE_DATA_OFFSET]) > > So the actual register is found by looking up offset IDE_DATA_OFFSET in > the array HWIF(drive)->io_ports[]. Yes, I understand. This is starting to make more sense. Here is what I have figured out: The first 8 offsets are normally 0-7, just like their array indexes. Index 8 and 9, IDE_CONTROLL_OFFSET and IDE_IRQ_OFFSET, were confusing me because I was expecting them to be the actual offset 8 and 9 -- and I could not find any IDE adapter data sheets that showed them located as such. Now that I take a second look at ide_std_init_ports(), I see that the CONTROL register is treated as a special case, i.e. it is not expected to follow the STATUS register in address space. This jives with what I have seen in data sheets. It looks like the example that Alan contributed does not update HWIF(drive)->io_ports[IDE_IRQ_OFFSET]. Or at least I cant figure out where. I am having trouble identifying this register in IDE data sheets. Is it one of the "not used" or obsolete registers? Do I need to be conserned with it? Thanks again. Bryan
