Understanding assembly question (1 Viewer)

[jc7726]

I've been studying for my sdd trial with some papers our teacher provided, but there's this one assembly question im stuck on:



Is the dissassembler section of "assembler code" not just each section of assembly code in order? I thought the output would start with 48 because that's the value put into R1 but that's not even close to the answer, so I don't think I'm understanding this question at all, is someone able to please explain it?

 

[dav53521]

Is the dissassembler section of "assembler code" not just each section of assembly code in order

The code execution is not in a linear order because of the jumpnz instructions jump to a label if the register given is not equal to 0 and as you can see one jumpnz goes to to the label "next" and the other goes to the label "loop" which creates a loop that will continue until R5 or R4 is are equal to 0.

 

[jc7726]

The code execution is not in a linear order because of the jumpnz instructions jump to a label if the register given is not equal to 0 and as you can see one jumpnz goes to to the label "next" and the other goes to the label "loop" which creates a loop that will continue until R5 or R4 is are equal to 0.

Yes but is it the order in which the original assembly code was written? Not necessarily order of execution but in terms of the order that it will go in unless affected by the jumps to 'next' or 'loop'.

I'm a bit confused because why does the output not start at 48? R1 is initially set to 48, R0 is 0, R3 is 2.
0 mod 2 is zero, so the program does not jump to 'next' because it is not a non-zero value, so R1 is stored to the register displayed in the console and it was never changed from 48 in that initial sequence

 

[jc7726]

What i understand from the code is that it is printing every second number, a multiple of 2, from R1 upwards repeating n-1 times if the value of R2 is 2n. But would this not make it go 48, 50, 52, 54, 56? In the answer it says it prints 0, 2, 4, 6, 8

 

[jc7726]

wait i think i get it.
by "treated as an ascii value" it means the decimal value will be converted to the ascii character associated with that number. ascii value of 0 is 48 and so on.

 

[dav53521]

Because it says ASCII value so you will have to know the ASCII table as decimal 48 in ASCII is 0 as seen in the table attached

 

[carrotsss]

Help with Trials question: interpreting a disassembler?

Hi all! This below question was in one of the trial papers from my teacher. If anyone could provide an explanation / walkthrough guide on how to approach this I would greatly appreciate it! Part 1: Part 2: Thank you!!!

boredofstudies.org

coincidence

 

[SadCeliac]

I've been studying for my sdd trial with some papers our teacher provided, but there's this one assembly question im stuck on:
View attachment 39387View attachment 39388
View attachment 39389

Is the dissassembler section of "assembler code" not just each section of assembly code in order? I thought the output would start with 48 because that's the value put into R1 but that's not even close to the answer, so I don't think I'm understanding this question at all, is someone able to please explain it?

I find this post hilarious because I posted the exact same question like a month ago https://boredofstudies.org/threads/help-with-trials-question-interpreting-a-disassembler.404105/

 

[dav53521]

I find this post hilarious because I posted the exact same question like a month ago https://boredofstudies.org/threads/help-with-trials-question-interpreting-a-disassembler.404105/

That's why I was able to recognize that question almost instantly even when I didn't read it properly.

 

[jc7726]

I find this post hilarious because I posted the exact same question like a month ago https://boredofstudies.org/threads/help-with-trials-question-interpreting-a-disassembler.404105/

i had no idea this post existed

 

[SadCeliac]

i had no idea this post existed

All good - this thread probably has a more comprehensive answer tbh

 

[SadCeliac]

woahh you guys learn assembly in SDD? that's legit what I'm doing rn :0

like we don't really learn it... we have to understand it

 

[jc7726]

like we don't really learn it... we have to understand it

Another question relating to the cpu, thought i would post it here instead of making a new thread: When is the program counter incremented? Is it immediately after it is fetched or after the process from the ALU is complete? Or is it both, as in it is set to/points to the next address in line unless/until a new address is sent to it after ALU processing?

 

[dav53521]

Another question relating to the cpu, thought i would post it here instead of making a new thread: When is the program counter incremented? Is it immediately after it is fetched or after the process from the ALU is complete? Or is it both, as in it is set to/points to the next address in line unless/until a new address is sent to it after ALU processing?

I believed it is after the current instruction is read in as after that the PC will be able to get the memory address of the next instruction which will increment the PC

 

[jc7726]

I believed it is after the current instruction is read in as after that the PC will be able to get the memory address of the next instruction which will increment the PC

So if there's a conditional jump statement returned true by the ALU, then this address will be overwritten before the next instruction is fetched?

 

[dav53521]

So if there's a conditional jump statement returned true by the ALU, then this address will be overwritten before the next instruction is fetched?

From what I hastily read if the condition for a jump is true then the instruction pointer is redirected to the label of the jump destination

 

[SadCeliac]

I had a question about the Fetch-Execute cycle in my trial paper --will send here once my teacher releases the paper (I think on Thursday??)

 

[sumum]

From what I hastily read if the condition for a jump is true then the instruction pointer is redirected to the label of the jump destination

Hey someone forwarded me to you @dav53521 . I understand from your posts on bored of studies that you do Comp Sci at uts but specifically the IDeA course. Can you give me some info on it. Some specific Questions are:

1. What atar did you need to get in?
2.What companies do you generally get paired with?
3. Is the jobs software development and software engineering (Because thats whatIm intrested in and NOT the business analytics of "boring" [to me atleast] side of stuff)
4. How is the pay?
5. How many times a week do you work for the company and is the balance good or do you feel overwhelmed with the Job Placement and the Uni work at the same time.

I may need to ask more questions abit later on if I get accepted after interview and atars.

Thanks alot!

 

[sumum]

From what I hastily read if the condition for a jump is true then the instruction pointer is redirected to the label of the jump destination

Also I made a conversation with you so you can reply there or here, Im not too sure how this app works

 

[jc7726]

I had a question about the Fetch-Execute cycle in my trial paper --will send here once my teacher releases the paper (I think on Thursday??)

thanks, exam is tmrw though (i really want to top bc my friend is beating me by 1 mark overall from the first exam)