I've been using ACME to write code for a 6502 board, and as the project grows I'm running into more issues with how ACME works (such as very odd behavior when separating the project into different files). I'm trying to look at all the assemblers out there but I just feel like I'm missing something.

Hoping for the following:

- Support for 65C02 and 65816
- Runs on/can be compiled on Linux
- Uses as standard syntax as possible
- Preprocessor directives like #include, #define, #ifdef, etc
- Anonymous labels (i.e. +/-). After using this in ACME I don't think I can do without it.
- The option to generate an output binary that includes a block of address space assembled to. I.e. for an EEPROM, I have code at $8000 and vectors at $FFFA..$FFFF and the output is a 32K binary.

Every assembler I come across is lacking one of these, but I'm sure they exist, so... what are y'all using

I personally use ca65. It seems to have everything you're asking for.

• It has support for the NMOS 6502, 65C02, and 65816.
• It has a native linux version
• Not sure what you mean with "syntax", it uses the standard mnemonics, $ for hex, % for binary, and the assembler doesn't care about whitespace so you can place labels and instructions pretty much however you want (within reason)
• Yes it has those, check the wiki page for all directives: https://www.cc65.org/doc/ca65-11.html
• they are called unnamed labels in ca65: https://www.cc65.org/doc/ca65-6.html (seems like a horrible feature for readability though)
• that just sounds like an .ORG directive. ca65 allows you to place code/data at specific addresses.

You likely never came across this because ca65 is just one part of the whole cc65 compiler utility: https://github.com/cc65/cc65
But it is still a fully functional standalone macro assembler, with the small detail that it generates object files that need to be linked, instead of regular binary files.
Which adds some effort in setting it up, but once set up you can just use a script to assemble and link automatically.

I use as65 from the cc65 suite. It does all you're after and can be command-line driven if that's your thing.

-Gordon

_________________
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Gordon Henderson.
See my Ruby 6502 and 65816 SBC projects here: https://projects.drogon.net/ruby/

That is insane, we posted our replies within the same minute and about the same assembler!
At least I assume we meant the same one, the assembler included with cc65 is called "ca65". And "as65" is a completely different assembler that only supports the 6502 and 65c02: https://github.com/hculpan/h6502/tree/master/as65

The names are confusingly similar.

Great minds thinking alike



You're right - and I always confuse them. Yes. ca65 from the cc65 suite.

-Gordon

_________________
--
Gordon Henderson.
See my Ruby 6502 and 65816 SBC projects here: https://projects.drogon.net/ruby/

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

CA65 from the CC65 suite is the assembler I use for serious projects.
Does support 65(C)02 and 65C816, and the assembler/linker combinations allow a lot. And it is cross platform, in source format.
Takes some learning of course, a configuration file is more complicated and powerful than one or more .org's.

While my target is mostly 65(C)02 I often used TASM (now the 32 bit command line DOS version on Windows) for smaller/less complex projects, where a couple of .orgs are sufficient.
Cross platform: VASM also is suitable for these kind of projects. Nick gammon did his G-Pascal program in VASM, and that is quite a big project!

CA65, as everyone has mentioned here, is a very good option. You may want to try Macroassembler AS as well to see what you think. I switched after getting frustrated with a couple of the macro features in CA65. It meets all of your requirements except being native to Linux. It runs fine for me on Ubuntu under Wine and is what I use for everything now.

EDIT: There is a Linux port too.

Thank you so much everybody!! Much appreciated. I knew you all would come through. Good to see there is some consensus.



In doing some research I see reference to some assemblers using non standard syntax requiring a lot of search/replace or hand reworking if you ever changed to another assembler. I think this is in regard to other assembler directives outside of basic mnemonics.



Ah, yeah it looks like the way they are implemented is not as clean as in ACME since the target label is not immediately apparent. I saw the same syntax in another assembler and it didn't look great to me. Either way, I'm open to doing things differently. I've become very used to doing something like this:



Without having to come up with a unique label name, leaving the code sprinkled with (to me, awkwardly named) labels. Looking at the link you send, the "cheap local labels" actually looks like it may be a better option.



I thought so, but came across compilers that would simply assemble code as if it were located at the current address, but that's it. I.e.:



Would simply assemble a 2 byte file, where ACME would fill in the unused space (with an available directive to specify the byte value to fill with).



Most likely! So glad I asked. I already have build scripts for my project so that's no big deal.

Thanks! I'll keep that in mind.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Good point Garth! Definitely something I have been thinking about.

I actually scanned through your site briefly looking for links to assemblers and I missed your links page unfortunately.

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

+1 for ca65.

You can see how I setup the memory map in my sbc-project here(as well as shell scripts for assembling and linking): https://github.com/AndersBNielsen/abn6502
Dunno if it's best practice, but it works very well.

_________________
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New new new new new video out! Serial Bootloader for my 65uino
Also, check out: I2C on a 6502 Single Board Computer
and Complete hardware overview of my 6502 SBC R1

ca65 is a good choice, but I'll put in a good word for 64tass (which you likely can just ask your Linux package manager for, and it's super easy to compile on systems that don't have a package). It doesn't require a configuration file like you might need to create for ca65. I haven't used it with a 65816 but 64tass lists it as supported. Here's some snippets of code (from a Forth implementation) that show several of the things you are looking for:
Anonymous labels:There are also "local" labels - use a label that starts with an underscore and it only exists between the surrounding non-underscored labels and the same name can be reused. Here is an example that uses _done: (used 79 times in this file):This assembler doesn't quite have #ifdef, but it does have .if and named lists which is what I use for configuring optional assembly.

By default the output is a .prg file (has two byte address at the beginning that say where to load it in memory), so I use the --nostart command line option to make binary ROM images.