add a, b
subtract a, b
compare c, d
jump_if_greater_than to_some_place

some_place:

You pretty much just need an overview on the processor architecture and the various opcodes.
Whilst this gives you a founding in the language, actually programming anything is a different matter.  Then again, you rarely need to program anything significant in assembly these days.

If you come from a higher level language, think of it as a really dumbed down simple, but highly verbose, language.
If you prefer a bottom-up approach, just think of an opcode as selecting a logic circuit from the ALU, and operands as feeding in data (or references to data).

Note: I don't actually do assembly programming, so this is just what I'm guessing.

(08/03/2012 05:57 PM)Tetris999 Wrote:  P.S. Forgot to whine about this, but my partner in my android program project is a useless and lazy douche that's in computer science "for the monayz" (he's an arts student, probably one of the kids who apply to UBC just to get in and then find out that there's reasons for application requirements and goes into computer science because "its the only thing worthwhile in arts", not hating on arts students, but arts students like THESE are scum).

(08/03/2012 07:27 PM)ProperBritish Wrote:  you read assembly right to left, and all of it revolves around registers or stacks (can't remember which) such as the EAX, EBX, ECX registers.

I did a section of my advanced programming on reading assembly, it's not hard to read. But to write, god help you.

(08/03/2012 07:27 PM)ProperBritish Wrote:  also PS Vita is programmed in C++ or C#, not assembly.
hell even PSP was programmed in C, not assembly.

you read assembly right to left, and all of it revolves around registers or stacks (can't remember which) such as the EAX, EBX, ECX registers.

I did a section of my advanced programming on reading assembly, it's not hard to read. But to write, god help you.

The compiler of PSSuite, which i have, the PS Certified DevKit for PS Certified devices and the Vita, will compile the program into whatever assembly functions it needs to do.

Never should you need to program anything in Assembly these days, unless you are writing an OS of your own or something that in-depth.

(08/03/2012 08:30 PM)ZiNgA BuRgA Wrote:  My guess is that he's interested in assembly for the purposes of hacking the device?
I can only really think of five reasons, off the top of my head, why you may need to use assembly:
- reverse engineering
- you need a lot of speed or more optimisation than a compiler can give you
- some features not available in higher level languages (eg how an OS needs to save all registers)
- some fancy code injection type stuff
- specific applications, such as compilers, emulators etc

If I ever do get into the hacking shenanigans, I better change my name, YOU DIDN'T HEAR IT FROM ME HERE!

(08/03/2012 08:22 PM)Assassinator Wrote:  Assembly language is generally very simple to learn (for RISC systems anyway), it's just very annoying to use.  If you want to program anything significant it'll end up massive so I suggest not doing that and using a higher level language instead.

Also, you probably shouldn't try to program any games until you're very proficient at programming.

(09/03/2012 05:10 AM)Tetris999 Wrote:  While that's definitely the case proper, I thought there are merits to assembly programming. As you said, yes, the C/C++/Java languages are basically templates to assembly code (as you give it to a compiler to interpret the statements to you) this makes coding easier to read but a much sloppier implementation.

int x=1, y=0;
while (x<5) {
    y+=x*(x-2);
    x++;
}

Ok, lets say you want the equivalent of this bit of c code in assembly

Assuming your machine has 3 registers R0 R1 R2.  (Now normally you have more than 3 registers, but normally your program is also way more complicated and needs a lot more variables, so it evens out).

Note: this is like simplified pseudo-code assembly.  I obviously can't be fucked learning the real ARM assembly language just for the purpose of this demo.

Store 1 R0   //Store value of x into register 0
Store 0 R2
Push R2      //Push the value of y onto the stack, because we don't have enough registers.
start_loop:
Store 5 R2
Jump_equal R0 R2 #exit_loop
Store 2 R2
Sub R0 R2 R1
Mult R0 R1 R1
Pop R2
Add R2 R1 R2
Push R2
Store 1 R2
Add R0 R2 R0
Jump #start_loop
exit_loop:
Pop R2      //This is the y you want at the end
End

Now imagine if you wanted to write a real program in assembly language, it's going to be a massive pile of mess, that's impossible to read and probably very annoying to debug.

(09/03/2012 05:10 AM)Tetris999 Wrote:  Having said that, I also heard that C is the closest you can get to assembly (as in, a language that implements it in it's design), and that you can actually mix the two together in a single program, pretty neat if you ask me. Which allows you to optimize your algorithms but at the same time not bothering to assembly program your print statements and such.

Actually I don't know this to be true, my prof told me this, though I don't think I misheard him.