Indirect addressing HELP

Hi guys,

New to indirect addressing is anyone able to help me with the attached file. I have tried the pen and paper method and first I put the source address to #19:2 and then I entered the data 3, 7 and 14 into the NEQ instruction. I checked the destination address and I received 73, 74 and 75. Next I changed the the source address to #19:3 and entered in the same data and this time I received 120, 80 and 560.
So based on your information I believe the starting addresses of the data are as follows:

Input 3 and the starting address is N73:120
Input 7 and the starting address is N74:80
Input 14 and the starting address is N75:560

Based on the above do you believe I have identified this correctly with respect to the pdf I attached?

Thanks again for your input.

Regards

Yes for 3
Yes for 7
No...14 gives you N75:80?

JohnCalderwood said:

Yes for 3
Yes for 7
No...14 gives you N75:80?

Click to expand...

I got the same thing... pen and paper method...7-5=2, 2x40=80. 14-12=2, 2x40=80. Seems legit to me...

miccyp87 - what is the source of this program selection?

It was presented before by Daniel81 also from Australia in this thread - http://www.plctalk.net/qanda/showthread.php?t=112267

first I put the source address to #19:2

Click to expand...

Are you saying that you are observing N19:2 then N19:3? Your wording seems to imply that you are modifying an instruction. The only number you should be modifying is the value in N11:18.

Is that actually you? Your description of testing with numbers is the same - word for word.

Is it a portion from a class? I wonder as the logic seems to have an error as I pointed out in the thread in the link above.

see students see sneaky....

bernie_carlton said:

miccyp87 - what is the source of this program selection?

It was presented before by Daniel81 also from Australia in this thread - http://www.plctalk.net/qanda/showthread.php?t=112267

Are you saying that you are observing N19:2 then N19:3? Your wording seems to imply that you are modifying an instruction. The only number you should be modifying is the value in N11:18.

Is that actually you? Your description of testing with numbers is the same - word for word.

Is it a portion from a class? I wonder as the logic seems to have an error as I pointed out in the thread in the link above.

Click to expand...

Nice catch! The .pdf attachments are exactly the same as well. I also wonder if this is for a class of some sort...

This list may help, but as already been mentioned N11:18 = 11 will cross the integer file N74 boundry into N75 overwriting N75:0 to N75:25 if my math is correct.

Steve

Not a student - our friend is going for a job with a certain OEM based in Mt Gravatt, this is one of their pre-interview tests

If a candidate points out that there is an error in the code do you think it would raise their chances?

Knowing a few of the engineers there, you would have to choose your words carefully when you pointed it out, or it could land you on the back foot fairly quickly

Not sure who is doing the interviews these days though.

A friend of mine went for (and got) a field commissioning engineer position with them 6 months ago. He showed me their questionnaire then, along with his answers. I heard from him a few weeks ago, he was in Algeria and heading from there through Germany, Turkey and Jordan. I hope the OP realises the extent of the travel that's involved in the position.

Although presumably they use the same questionnaire to interview for the office-based development engineers as well, so perhaps OP is after a desk job

Thanks guys yes its for pre check on your skills, I have never been exposed to indirect so I thought I would ask the question. I did read the other thread and got the same answers using pen and paper the only thing was the limit test on one throwing me off. Now I completely understand everything I'm looking at.

I didn't chase down all the code but I line 00 NEQ N11:18 should be changed to LES 255 if you entered a number larger then 255 you would get an indexing error and crash the processor it would point to an address out of the range of the file. there are other errors as well pointers pointer to non existing addresses will cause the processor to crash.