>
>You are talking about the three "shadow" registers that holds
>the values of W, STATUS and BSR during the interrupt, right ?

Yes

>(In the data sheets they are called WS, STATUSS and BSRS, but
>they are not normal SFRs or memory mapped, so you can not "see" them.)
>
>You could call it "hiding", since it's done behind the curtains.
>There are no additional cycles wasted, the interrupt as such
>takes as much time as it does on the PIC16, but there you have
>to save those regs yourself and *that* will take a number of
>cycles.
>The net effect is that interrupts on the PIC18's are faster then
>on the PIC16's (in general). If it's a very short ISR, the difference
>could be significant.

You've lost me.

If the regs are saved in parallel in hardware, then I wouldn't call that 
"hiding" anything, and it would be faster.

If the regs are saves sequentially in microcode, and there's no timing 
difference between you doing it in the ISR and the automatic version, then 
I would call that "hiding" the save/restore overhead.

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