If you want a really extreme optimization for or-ing the screen, here it is.  It will be noticeably faster and smaller:

.# represents the 16-bit or operation
L₆→A
While -768-L₆
{A}ʳ#{A+L₃-L₆}ʳ→{A}ʳ+1→A
End

That's pretty much the way to do it. You'd be surprised just how fast one massive For() loop that OR's the contents of both buffers is, though. I calculated that the following loop runs about 40 times per second at 6MHz:

Code: [Select]

Repeat getKey(15)
For(A,0,383)
.That ﹢ symbol is the 16-bit OR operator
{A*2+L₆}ʳ﹢{A*2+L₃}ʳ→{A*2+L₆}ʳ
End
C+1→C
End

Whoa, how'd you get the small ^r to work in a code tag?

Quote from: Runer112 on October 02, 2010, 12:14:28 pm

That's pretty much the way to do it. You'd be surprised just how fast one massive For() loop that OR's the contents of both buffers is, though. I calculated that the following loop runs about 40 times per second at 6MHz:

Code: [Select]

Repeat getKey(15)
For(A,0,383)
.That ﹢ symbol is the 16-bit OR operator
{A*2+L₆}ʳ﹢{A*2+L₃}ʳ→{A*2+L₆}ʳ
End
C+1→C
End

Whoa, how'd you get the small ^r to work in a code tag?

"ʳ"  There is a symbol for it. Just copy/paste.

woah, that's one extreme optimization and routine :O

I will have to study the code hard to understand it but I'm glad to see it is possible to do that. Thanks a lot

I would hope a for loop is faster, though Quigibo will have to back me up on this.

A while loop is better if you can avoid a comparison operation and use the "0 is false everything else is true" instead:

For(A,0,5)
<code>
End

0->A
While -5
<Code>
A+1->A
End

The second one is actually smaller and faster than the first one.  The only reason I can't make this the default behavior for the for loop is actually because if A happens to be above 5 in this example, it would keep counting up until it passes 65536 and loops back to 5 again.  You're basically coding a less optimized for loop here but since you skip the comparison, it actually makes it 1 byte smaller and negligibly faster.

And using a While loop, you can use steps other than 1


Edit:
I got somewhat ninja'd, so I was still talking about For( loops.

True. And just wondering: Does anyone have an example of where DS<( would be useful?

DS<() Is useful when you have something in a loop/interrupt that you don't want to run every iteration. For instance, if you want to update the screen in a program's main loop or in an interrupt but don't want the screen updating too often (to save processing power for other things), enclose the screen updating portion in something like DS<(A,4) so the screen is only updated every fourth iteration.