Hi Everyone,

I noticed in the data-sheet for the 65C02 that the # of cycles for a branch
is 2 (taken or not taken).

How can this be? If the branch is taken, wouldn't it need a third
cycle to add the displacement to the program counter. Remember, during the second cycle the displacement was only being fetched.


Thanks,
Bye,

Paul

The base count is 2 clocks. There should be a foot note saying to add 1 clock if the branch is taken, and one more (totaling 4) if a page boundary is crossed when the branch is taken. The majority of branches will be within the same page however. BRA will usually take 3, but 4 if you cross a page boundary. JMP absolute always takes 3.

Garth

Hi Garth,

Thanks much for clarification. This will allow me to get
some sleep tonight. Gosh, though, you would think
that the latest data-sheet from WD would show the correct
number.

Thanks again.

Bye,

Paul

Hi Everyone,

Correction!

Table 3-2 does have foot-note
that says add a cycle for the
branch taken case. Table 5-4
is also complete.

Sorry for the inaccurate previous post.

Bye,

Paul