Reading the difficulty switches on the 7800?

[PacManPlus]

Hi!

 

I hope someone can help me - can anyone tell me how to read the difficulty switches on the 7800 in 7800 mode? (Example code would be great!) I'm working on something where I need to read both switches. Thanks in advance!

 

Bob

[Bruce Tomlin]

It works exactly the same as on the 2600.

[PacManPlus]

Thanks Bruce

 

For some reason I thought it was different...

 

I think I have a commented Adventure disassembly I can look through to see how they read them.

 

Thanks again

[Harry_Dodgson]

Hi!

 

I hope someone can help me - can anyone tell me how to read the difficulty switches on the 7800 in 7800 mode?  (Example code would be great!)  I'm working on something where I need to read both switches.  Thanks in advance!

 

Bob

853217[/snapback]

 

How about something like this? :-)

 

BIT Swchb

BVS p0expert

BVC p0amateur

BCS p1expert

BCC p1amateur

[vdub_bobby]

Hi!

 

I hope someone can help me - can anyone tell me how to read the difficulty switches on the 7800 in 7800 mode?  (Example code would be great!)  I'm working on something where I need to read both switches.  Thanks in advance!

 

Bob

853217[/snapback]

 

How about something like this? :-)

 

BIT Swchb

BVS p0expert

BVC p0amateur

BCS p1expert

BCC p1amateur

853952[/snapback]

 

:!:

The 'bit' instruction puts bit 7 into the sign flag, not the carry flag!

And also, in that code the last two lines will never be reached.

Try this instead:

   bit SWCHB
  bmi P1Expert
 ;--else P1 novice
  bvs P0ExpertAndP1Novice
 ;--else P0 novice and P1 novice
 ;--code here
  jmp Done
P0ExpertAndP1Novice
 ;--code here
  jmp Done
P1Expert
  bvs P0ExpertAndP1Expert
 ;--else P0 novice and P1 expert
 ;--code here
  jmp Done
P0ExpertAndP1Expert
 ;--code here

Done