[hatari-devel] Floppy emulation in fdc.c

["Roger Burrows" <rfburrows@xxxxxxxxx>]

I was trying to figure out the hardware register at $860f on a Falcon, so I 
looked in Hatari's fdc.c.  I saw the comments around line 4600, which helps a 
bit.  I have an extra piece of info for you Hatari folks (you may know this 
already): during a write sector or write track sequence, TOS4 sends a large 
sector count to the DMA sector count register, then loops waiting for bit 3 of 
$860f to become zero before it selects the FDC command register and sends the 
FDC write track command.  So bit 3 seems to act as a sort of "DMA/FDC busy" 
indicator.  But it must be a bit more complex than that, because it isn't 
tested during a read sector sequence.

While looking through fdc.c, I noticed the following in 
FDC_Get_Statusbar_Text(), around line 692:

=============
else if ( ( Command & 0xe0 ) == 0x50 )	strcpy ( CommandText , "SO" );		/* Step 
Out */
=============

Shouldn't that be 0x60 instead of 0x50?  Not very important, of course, since 
it only affects the status bar display.

Roger