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# Tech Society 2.0 watch

1. Yoo is anyone here knowledgeable in the area of ipod touches?
2. (Original post by spikeymike)
Straightforward?! Perhaps the coding is... but I don't understand where the numbers after the semi colons are coming from - how did the simulation come to these numbers?. i.e. example dissembler data from http://pcplus.techradar.com/node/3166/

Code:
```00 JMP 0 ; 0
01 LDN 18 ; 16402
02 LDN 19 ; 16403
03 SUB 20 ; 32788
04 CMP ; 49152
05 JRP 21 ; 8213```
Care to explain?
The last number is the output if you took the complete instruction given(i.e everything on the line before the semicolon) in its 32 bit binary form and converted that into decimal. The first 5 bits of this binary instruction are depict what line number to operate on(so for the first instruction, the first 5 bits are 18 in 5 bit binary), and bits number 13, 14 and 15(starting from bit no 0 on the left) are the binary representation of the instruction itself(LDN/SUB/JMP).
Does that help?
Edit: This might be a premature warning, but one of the things you will have to do is convert b/w binary and decimal. Make sure you do it according to what the actual machine did(the baby used 2's complement to represent negative numbers), I spent a fair bit of time doing it wrong and then fixing my code.
3. (Original post by ish90an)
The last number is the output if you took the complete instruction given(i.e everything on the line before the semicolon) in its 32 bit binary form and converted that into decimal. The first 5 bits of this binary instruction are depict what line number to operate on(so for the first instruction, the first 5 bits are 18 in 5 bit binary), and bits number 13, 14 and 15(starting from bit no 0 on the left) are the binary representation of the instruction itself(LDN/SUB/JMP).
Does that help?
Edit: This might be a premature warning, but one of the things you will have to do is convert b/w binary and decimal. Make sure you do it according to what the actual machine did(the baby used 2's complement to represent negative numbers), I spent a fair bit of time doing it wrong and then fixing my code.

01 LDN 18 ; 16402

Could you just explain what is happening here? And where 16402 is coming from? 2^14 + 18? Why are the first 5 bits 18 in 5 bit binary for this instruction?
4. (Original post by spikeymike)

01 LDN 18 ; 16402

Could you just explain what is happening here? And where 16402 is coming from? 2^14 + 18? Why are the first 5 bits 18 in 5 bit binary for this instruction?
The first number says "this is the first line to be executed". LDN says "load the negative of the number from the store location n", and 18 is the "n".
Now, if you were to take LDN 18, and convert 18 into 5 bit binary and LDN into its 3 bit binary equivalent(from the table on wikipedia), and form a 32 bit binary number whose first 5 bits=18 in 5 bit binary and the 13-15th bits were the LDN bits, you would get the binary equivalent of 16402. This 32 bit number is in fact the instruction the SSEM used to take in.
The 5 bit binary thing is because the store(which was the SSEM's memory) was limited to a size of 32(2^5) in the original machine, probably due to hardware constraints.
Since you don't program at the level of binary, what you do is read in a program containing some 32 bit instructions(probably as strings), and per instruction read the first 5 bits to form the store location and the 13th, 14th and 15th ones to form the operation to perform on the data in that location. You then execute it and increment to the next instruction(or jumping to one if that is what the instruction you execute says).
5. Give me some good music to listen to peeps
6. (Original post by secretmessages)
Give me some good music to listen to peeps

aha

funky remix
7. (Original post by alexsheppard11)

aha

funky remix
better than the original tbh
8. (Original post by Antipannenkoek)
Yoo is anyone here knowledgeable in the area of ipod touches?
I have one, what's your questnion?

(Original post by secretmessages)
Give me some good music to listen to peeps

9. Anyone know where I could get FTK 2.2?
10. (Original post by ish90an)
The first number says "this is the first line to be executed". LDN says "load the negative of the number from the store location n", and 18 is the "n".
Now, if you were to take LDN 18, and convert 18 into 5 bit binary and LDN into its 3 bit binary equivalent(from the table on wikipedia), and form a 32 bit binary number whose first 5 bits=18 in 5 bit binary and the 13-15th bits were the LDN bits, you would get the binary equivalent of 16402. This 32 bit number is in fact the instruction the SSEM used to take in.
The 5 bit binary thing is because the store(which was the SSEM's memory) was limited to a size of 32(2^5) in the original machine, probably due to hardware constraints.
Since you don't program at the level of binary, what you do is read in a program containing some 32 bit instructions(probably as strings), and per instruction read the first 5 bits to form the store location and the 13th, 14th and 15th ones to form the operation to perform on the data in that location. You then execute it and increment to the next instruction(or jumping to one if that is what the instruction you execute says).
Ahhh... I see... I wondered what the instruction format was all about... (#2.5 http://www.cs.manchester.ac.uk/other.../progref1.html)

It is quite simple really. Thank you so much!
11. (Original post by Dez)
I have one, what's your questnion?

12. (Original post by secretmessages)
Philistine.

13. Roooooxxxaaannnneeee!!

Craaaiiig Davviiddd.
14. I am looking forward to the new 3.8 being ushered in
15. I'm looking forward to a weekend full of drinkage... and maybe some award winning too.
16. Oreos
17. (Original post by alexsheppard11)
the old hard drive was 300GB... not 320GB
Formatting? Same way a standard hard drive in a computer will have less actual space than the manufacturer stated capacity,

(Original post by secretmessages)
I wonder why 160, 250, 320, 500 are standard sizes . It seems like an odd selection.
(Original post by secretmessages)
I suppose I can understand 160, 320, 640 as it's 10*2^x who knows
Well, the 500 will usually come from two 250GB platters, but I don't know how they got 250 on a single platter. I'm guessing it's they did 10*2^4.64385619.
I actually got an automated requests warning and captcha from Google while trying to work that out xD

Apparently, they got 180GB/sq inch
Formatting? Same way a standard hard drive in a computer will have less actual space than the manufacturer stated capacity
it says 300GB on the disk itself
19. (Original post by alexsheppard11)
http://sheppardclan.f2s.com/alex/sky/

CNPS-9700!!!!! <3

(Original post by alexsheppard11)
it says 300GB on the disk itself
As in, the actual disk capacity is 300GB? That would be a 320GB drive, right?
20. (Original post by spikeymike)
Though that smily is wrong because I've gone off beer, cider ftw.
My sister is watching the budget live on BBC.
Bad news for you. Cider tax is going up. 10% above inflation.

/ffffuuuushield on

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