A 32-bit read/write with %io-port-read/write-succession

Hi guys,

I had a quick question about this function and its macro helper.  If I'm
understanding correctly, %io-port-write-succession would shift a 32-bit
number by a 2-bit offset, write 30bits, then write the unwritten 2-bits?

Is "io-port-w/r-succession" the preferable way of doing a 32-bit
transfer to registers, or is the shifting method Peter Minton used in
his harddisk LBA'ing preferable?

Thanks
-Elliott

ps- is this sort of 2 stage writing to registers ok?  I'd think most
synchronous read or writes would want to be performed in a single cycle?