Hi Clive,

My IAR compiler has a switch for enabling code generation for dual DPTR, and its simulator handles it. Of course it should, given how much they charge for it.

Depending on what you're trying to do and how fancy you want to get, it's also possible to write your own simulator. I did, when I needed to do some timing calculations when I switched to a Winbond part (mostly 4 clocks per instruction, like Dallas).

Winbond also makes a dual DPTR parts, for what it's worth.

Dennis