To create a goodos you must have a good compiler
I'm building a basic compiler but i don't have any experience.
I would like to have only suggections.
Thank ou.
Creating a compiler
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carbonBased
RE:Creating a compiler
There's a great from-scratch tutorial (using Pascal code) written by Jack Crenshawe. I'd take a look at that for some ideas on where to start.
Personally, I wrote a tokenizer first, and then built upon it. The tokenizer breaks up the input string into tokens (which are defined in a global array along with a made up "token number" (easier/faster to use once you've broken up on the strings). The tokenizer adds each token to a linked list, but in an altered order (in other words, order of operations, etc, are taken care of by the tokenizer).
For eg.
y = 4 * (2 + 3)
equates to
2, 3, +, 4, *, = y
On my linked list.
Which the second phaze interprets as:
mov ebx, 2
mov eax, 3
add eax, ebx
mov ebx, 4
mul ebx
mov eax, [y]
(or something to that effect... I haven't had the time to work on it much lately, so I can't remember everything completely).
With this two pass method, I find it a lot easier to optomize code. For example, after tokenizing, you can skim through the linked list, and find code that does nothing (ie, "y, 1, *, = y" or "y = y * 1" can be completely ignored.)
If you're interested, the source code to the current version of my compiler can by found on my web site at www.neuraldk.org Hopefully soon I'll have a much more advanced version, but this one is fairly functional, and works with basic arithmatic (including brackets and variables), and supports quite a few constructs -> C style for loop, do {} while/until, while/until {}, if)
Jeff
Personally, I wrote a tokenizer first, and then built upon it. The tokenizer breaks up the input string into tokens (which are defined in a global array along with a made up "token number" (easier/faster to use once you've broken up on the strings). The tokenizer adds each token to a linked list, but in an altered order (in other words, order of operations, etc, are taken care of by the tokenizer).
For eg.
y = 4 * (2 + 3)
equates to
2, 3, +, 4, *, = y
On my linked list.
Which the second phaze interprets as:
mov ebx, 2
mov eax, 3
add eax, ebx
mov ebx, 4
mul ebx
mov eax, [y]
(or something to that effect... I haven't had the time to work on it much lately, so I can't remember everything completely).
With this two pass method, I find it a lot easier to optomize code. For example, after tokenizing, you can skim through the linked list, and find code that does nothing (ie, "y, 1, *, = y" or "y = y * 1" can be completely ignored.)
If you're interested, the source code to the current version of my compiler can by found on my web site at www.neuraldk.org Hopefully soon I'll have a much more advanced version, but this one is fairly functional, and works with basic arithmatic (including brackets and variables), and supports quite a few constructs -> C style for loop, do {} while/until, while/until {}, if)
Jeff
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carbonBased
RE:Creating a compiler
Mine is much more tight then Crenshawe's compiler.
Once I'm finished the basic compilation, I'm going to create a peephole optimization phaze to the compiler, which'll produce even tigher code.
However, if you want the most tight code, output to C, and compile through GCC
Jeff
Once I'm finished the basic compilation, I'm going to create a peephole optimization phaze to the compiler, which'll produce even tigher code.
However, if you want the most tight code, output to C, and compile through GCC
Jeff
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drwatts
RE:Creating a compiler
If you would like, I am in a class right now concerning compilers, and have a small, quick C++ compiler which currently supports switch statements, for loops, while loops, and a number of other commands. It does convert C code directly to assembly, although some methods are not quite efficent enough yet. However, if you would like to have a copy of the code, please send me an e-mail at [email protected]. Good luck in your endeavours.
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eox
RE:Creating a compiler
if you need a good compiler, why don't you just use watcom?
that would save a lot of time -> more time for osdev
that would save a lot of time -> more time for osdev