4 replies to this topic

[atari2600land]

why can't I do this:

 p=(player0x-57)/4
 if o{1} && k>9 && a{p} then k=0 : l=0 : m=0 : n=0

and what is a workaround to it?

[Random Terrain]

I thought curly brackets could only have 0 through 7 in them, representing the 8 bits?

[atari2600land]

But what if, in my example, I make it so p can't be higher than 7?

[Random Terrain]

atari2600land, on Sat Oct 15, 2011 3:59 AM, said:

But what if, in my example, I make it so p can't be higher than 7?

This seems familiar. There is a possibility that SeaGtGruff or RevEng talked about this subject before.

[RevEng]

Random Terrain, on Sat Oct 15, 2011 4:31 AM, said:

This seems familiar. There is a possibility that SeaGtGruff or RevEng talked about this subject before.

It might have been SeaGtGruff or batari... I don't think it was me.

The reason a variable doesn't work in a bit position check is that bB creates different assembly code lines depending on which bit position you've selected, in order to use the most efficient approach.

As a work-around you need to write your own more-flexible/less-efficient code to check the bits.

atari2600land, here's your original example with a flexible check...

  p=(player0x-57)/4
  temp1=bits[p]&a
  if o{1} && k>9 && temp1<>0 then k=0 : l=0 : m=0 : n=0
 
  data bits
  %00000001, %00000010, %00000100, %00001000
  %00010000, %00100000, %01000000, %10000000
end