Got another one. I'm trying to port a program for the 65c816, and I encountered this bit of code:


My assembler doesn't like the "$+5". I think the code is trying to advance the PC five addresses forward, if the carry flag is cleared,in which case I think I could do:


Is this correct, anybody? I've not encountered "$+" before.

Jon

Does it work with *+5?

To remove confusion, I'd be inclined to replace them with labels though.

so:



and so on.

-Gordon

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

Great idea! There are thousands of lines of code, so it would be hard to debug. The other item I'm having trouble with is this:


It is telling me that this is an "Unsupported format of parameters" with regards to .dword ((((P-'@')<<5)|(Q-'@'))<<5)|(R-'@')

Argh!

It's taking three characters and packing them into a 16 bit word. P is given the top 6 bits, Q is given the next 5, and R the lowest 5. @ is encoded as 0, A as 1, B as 2, and so on. Unwrapping it: P-'@' subtracts the code for @ from P, giving 0, 1, 2, ... Then it shifts that up 5 bits. Q-'@' does the same to Q, these two result get ORed together by the |, then the result of that is shifted five bits up. Finally the value from R gets ORed in.
Your assembler obviously doesn't like this expression as it is, but I couldn't guess exactly what it's complaining about. It's not the most helpful error message. I'd start by stripping the expression down the the bare minimum and gradually adding bits back until it fails. So

and so on. Knowing which bit of syntax it's unhappy about will help a lot in trying to write something that it does like.

It's compressing 3 characters into 2 bytes. Woz did this in his disassembler and one-line assembler. If this is failing for you, then your assembler doesn't support those actions, so short of changing assembler, you might need to work it out the hard way.

Although checking now - .dword - that might imply a double word and maybe 4 bytes, so compressing 3 characters into 4 bytes is odd, so I guess it really means a 16-bit word. I checked it in ca65 and it seems OK, but the syntax is different, so:



works with the output:



So, L,D,A -> $81, $30.

-Gordon

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

No matter how I try, it just won’t work - word, double word, bytes, etc.

This is driving me bananas.

Can you link us to your assembler's documentation, if any? There should be a way to get the job done without hand-translating and hard-coding the hex data.

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Mike B. (about me) (learning how to github)

Mike,

Here it is: https://enginedesigns.net/download/retroassembler.html

Thanks!

Jon

_________________
x86?  We ain't got no x86.  We don't NEED no stinking x86!

It didn't work with .word, but it did work with .textz . Weird.

It's telling you something is wrong with 'P', 'Q' , and/or 'R'. The expression itself is not a problem as the documentation says all the operators used are supported (same as C syntax).

Perhaps the problem is that P, Q, and R are not interpreted as characters but as labels? Subtracting a character from a label won't work. Are you writing



instead of



by any chance?

Also '.dword' generates a 32-bit value. Better is '.word' to generate a 16-bit one.

_________________
x86?  We ain't got no x86.  We don't NEED no stinking x86!