I'm not sure if this is the correct list for this question but:

	I plan on writing a device driver for a PCI card.  I would like the same
	source to work on sparc, sparc64, and i386.  Are there any issues betwen
	the 32-bit sparc and i386 and the 64-bit sparc64 of which I should be
	aware?  I'm expecting to be calling hton and ntoh to deal with the endian
	problems...

Hm.  PCI on 32-bit sparc machines?

Take a look at bus_space(9) and bus_dma(9).  Also, look at the way existing
drivers are put together.

You should only use hto[bl]e{16,32,64}() calls for data you will transfer
to the device through DMA.  The bus_space(9) accessors should handle
any endian issues themselves.

Eduardo