Add $2134-$2136 to debugger Properties Viewer

[koitsu]

WARNING: This has not been tested in any way/shape/form (may not even compile cleanly).

Reference: http://forums.nesdev.com/viewtopic.php?p=186767#p186767

[devinacker]

A couple of things: I'd prefer to keep the entire value as one line item, similarly to $2181-$2183, etc. Also, the way it's implemented right now will show the last values read by the CPU, not necessarily the actual current values.

If any extra variables are going to be added to store the multiplication result, it should be updated when the products are written, rather than when the results are read. But I think I'd prefer to just do the multiplication on-the-fly when displaying the value in the properties window, since it's never updated frequently enough to be a performance concern, and it wouldn't have to break existing savestates by adding more stuff to the serializer.

[koitsu]

Understood. I'll try to rework most of this. I'm not sure how to go about accomplishing the latter part ("only do the multiplication on-the-fly when displaying the value in the properties window").

[devinacker]

Something like this would be fine (maybe a bit heavy on the parens though):

item("Multiplication Result", string("0x", hex<6>(((int16)regs.m7a * (int8)(regs.m7b >> 8)))));