Decent Simplification Algorithm for C++

[kfreezen]

I'm working on an assembler for my OS's emulator bytecode. Does anyone know of an algorithm to simplify?
for example:
input:

Code: Select all

5 * 2 + 4 - ( 2 + 5 )

output:

Code: Select all

7

[ru2aqare]

I'm working on an assembler for my OS's emulator bytecode. Does anyone know of an algorithm to simplify?
for example:
input:

Code: Select all

5 * 2 + 4 - ( 2 + 5 )

output:

Code: Select all

7

Look up 'constant folding' in books about writing compilers. If you parse the expression as a tree, then it is pretty trivial to perform this.

[kfreezen]

Thanks, that should help me.

[kfreezen]

Is there also a decent precedence determining algorithm?

I have a feeling there isn't

[NickJohnson]

I think what you're really after is the shunting yard algorithm, which converts/evaluates infix expressions and accounts for order of operations. Wikipedia has a good article on it. It also doesn't require making a tree, assuming that the expression can be evaluated at compile time.

[Thomas]

Hi,
See : http://forum.osdev.org/viewtopic.php?f=13&t=21349

--Thomas

[kfreezen]

Yeah, I saw that one by the time someone had already replied to my thread and realized that that one would be the one I was lookin' for. Sorry I didn't search the forums first