7.6.5 Applying Offsets to Bits within a Variable or Register

[retepsnikrep]

I'm a bit confused by this so I'll pose my question.

I have a byte variable alias called "Config"

Using the offset bits technique can I manipulate bits by doing

Config.0[x] = 1

x being 0 to 7 in this case

The example in the manual uses a port alias for the demo.

Can x be another variable?

[Charles Linquis]

Yes, it can.

[sayzer]

.....
Can x be another variable?

Did you mean "Variable" other than Byte in your case, or Value other than 0 ... 7 ?

[Charles Linquis]

It actually works both ways.

X var byte
y var byte
z var bit

X = %01010101

Y = 3
Z = X.0[Y]
Z = 0

Y = 4
Z = X.0[Y]
Z = 1

[sayzer]

x = 125
Config.0[x] = 1

?

[Ioannis]

Maybe bit 5? That is 0.

Ioannis

[Charles Linquis]

I don't understand the confusion.

X var byte
y var byte
z var bit

X = %01010101

Y = 3
Z = X.0[Y]
Z = 0


X is a variable, Y is a variable. Bit 3 of X is a '0'

Y = 4
Z = X.0[Y]
Z = 1

Bit 4 of X is 1

[rsocor01]

I don't understand the confusion.

Sayzer wants to know what happens if Y > 7. I don't know the answer to that either. For example,

Y = 8
Z = X.0[Y]
Z = ???

[Charles Linquis]

It depends on the position of the byte in memory, and is generally unpredictable. You can, however play some tricks with it.
If you assign vars like -

X var byte
Y var byte

Then PBP will assign the bytes to consecutive memory locations. In that case, bit 8 of X will be bit 0 of Y.

[sayzer]

Sayzer wants to know what happens if Y > 7. I don't know the answer to that either. For example,

Y = 8
Z = X.0[Y]
Z = ???

I was just referring to the question in the first post.
I already know that what happens might not be what you would like to get.