Procedures

[julesjacobs]

What is the best way to create/call procedures? Which argument-passing-styles are available?

Thanks in advance,

Jules

[Narue]

>Which argument-passing-styles are available?
Um, all of them.

>What is the best way to create/call procedures?
It depends on your needs. It could be as simple as a jmp there and back to a full call/ret pair with a stack frame and all of the glitz and glitter that high level languages provide.

What are you trying to do?

[julesjacobs]

I'm trying to find out what the best method is for a stack based language. I have a book about assebly that says that the best way is to save registers on the stack, call procedure, and when it's done, pop the registers back. I don't think this is good for me because most data isn't in the registers, but on the stack.

I thought about the "marking return addresses" method you said in the other post, but I don't what's the best way to do it.

For example if the stack is:

bottom => top
data:6 addr:234 data:3

And we're at the end of a procedure, should I move down the stack pointer until there is an address (so skip data:3, and move to addr:234), and jmp? Then the data above needs to be restored so the stack should look like this now:

data:6 data:3

(the addr:234 should be taken out)

I don't know if this is a good/natural way to do it because it looks really ugly.

Also, I assume that you meant that I reserve the first bit of everything on the stack to indicate if this is an addr or data. (so 1 means addr and 0 means data for example).

[huffstat]

Thats the assembly language game, keeping track of what is on the stack and where it is. Oh yea, the stack is only so big. No stack overflows allowed or you are in trouble.

[julesjacobs]

Narue said that I should mark the address of return values on the stack. I'm not sure if this is a good way, but couldn't I just use 2 stacks, and change the stack pointer to switch to the other stack? (I would need to store the other stack pointer in an other register then). Or this it better to mark the values? (eg, set the first bit to 0 if it is a return address, set it to 1 if it is a value/pointer).