A recent post to comp.arch.embedded about porting 6502 code to the ST7
(a microcontroller from ST) caused me to peruse the ST7 programming manual
and at first glance it looks like a super set of the 6502.

I wonder if any one here is familiar with the ST7 and/or knows
how compatible it may be.

It looks (again, at first glance) like it may be intended to be
instruction compatible (or close to it) though perhaps not code compatible

Hi Everyone,

Some of the insructions/register-set look similar. However, another
key point is how are the flags affected by each instruction. Maybe the carry bit is set on over-flow instead of being cleared?

Cheers,

Paul

According to an ST ap. note, the ST7's interrupt sequence and return take four times as long as the new off-the-shelf 65c02's.

Hi Everyone,


Interesting. This is a draw-back to many processors.
The internals are probably micro-coded.


Cheers,

Paul