Assembler Code Deciphering (beginner)

[BobSparky1996]

XORWF X,w
btfsc STATUS, Z

Please could someone tell me what these two lines of code mean?

- Bob

 

[MaxHeadRoom78]

XORwf is one way of toggling certain bits when the word used has any bit that is set to toggle the subject bits..
IOW
XXXX XXXX
0000 1111
the result will be the LSB gets toggled in the upper subject word.
The next instruction is skipped if the result of the XOR word is zero.
A way of testing a register for a certain value.
Max.

 

[BobSparky1996]

Okay brilliant thanks Max!

- Bob

 

[MaxHeadRoom78]

Would have to see your hardware diagram, how are you reading the Pot?
Max.

 

[jpanhalt]

Welcome to ETO.

Your code will be easier to read if you use code tags to post it like this: [code=asm] place code here [/code]

As for the code itself, you are moving the value 100 to a counter and decrementing that each loop until it equals X (max value 30). If not equal to counter, you delay 100 us, decrease counter, and loop. When equal to X, you set an LED then continue looping until counter =0 and skip to something else.

One concern, assuming that interpretation is correct, is that 100x 100 us + a few instruction cycles = 10 ms + a little. I don't think you will see anything change. At least, the flask will be quick.

John

 

[BobSparky1996]

Cheers