Bits, Bytes Words and Arrays

[anj]

Gday Melanie
I just read this post and found it quite interesting.
On 6mar2004 i posted on the Picbasic Pro forum, re Accessing the PICs ports in subroutines.
Particularly the ability to access ports not covered by the std 0..15 references.
I never found anything on this in the manual, but it meant i could put direct port addressing into subroutines, by always addressing the required port relative to porta.0 .
Maybe you could modify this post to include access to ports by the referential aliasing method as well?
Just a thought.
Andrew

[khoog]

Found this interesting bit of ancient history. It covers all the options except the one I'm looking for. I need to put some words into a byte array.

settings VAR byte[1]

counter1.byte1 VAR settings[0]
counter1.byte0 VAR settings[1]

-does not appear to work

Klaus

[Darrel Taylor]

6. How can I reference a WORD in a BYTE ARRAY?

Let's say that you have a WORD located at bytes 3 and 4 of a BYTE array, and Byte 3 is the LowByte. You can use the EXT (external) modifier to assign it to a WORD variable.


MyByteArray VAR BYTE[10]

MyWord VAR WORD EXT
@MyWord = _MyByteArray + 3

[khoog]

Thanks Darrel,

Your example will put the low byte into the array. How do I get the high byte in?

MyByteArray VAR BYTE[10]
MyWord.byte0 VAR MyByteArray[3]

or

MyByteArray VAR BYTE[10]
MyWord.byte1 VAR MyByteArray[3]

will work as well.

I can read in either the high or low byte, but not both of them.

[Darrel Taylor]

It creates an Aliased WORD variable, inside the BYTE array.

When you assign a value to the WORD variable, it puts both BYTEs in the array in a single operation.

MyWord = $1234

will make MyByteArray look like this

[00, 00, 00, 34, 12, 00, 00, 00, 00, 00]

HTH

[khoog]

Thanks again Darrel. That's almost too slick to be true. When you start throwing around those "@" signs it becomes a little mystical for me.

I will try it and let you know.

[shahidali55]

After searching the whole forum for an hour or so i stumbled upon this page.
Finally i can dynamically access bits of a variable. This has really helped me a lot.
Thank you Melanie .