3

I am trying to move my project from xa (which I found rather buggy) to crasm, which is the other 6502 assembler that comes with debian.

My project contains a lot of lines like

ldx #<pname
ldy #>pname

where pname is a label where a string may be found. How is that done in crasm? I couldn't find any such thing as < and > in the man page.

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    What's your target platform? Something like 64tasm or cc65 might be a better choice. – fadden Nov 6 '18 at 21:36
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    That's an idea. I'm writing for the c64. And you just reminded me that cc65 comes with an assembler. – Wilson Nov 6 '18 at 22:05
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    I can certainly endorse ca65. It's pretty powerful for a 6502 cross assembler. It also comes with a nice disassembler. – JeremyP Nov 19 '18 at 15:51
  • @JeremyP, when I tried ca65 I got a load of extraneous fluff in my binary, including what looked like symbol tables and other linker's business. Do you know what I'm doing wrong there? – Wilson Nov 19 '18 at 16:13
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    That sounds like its given you an object file that still needs to be linked. Does the result have a .o extension? – JeremyP Nov 20 '18 at 14:03
6

CRASM is .. well ... lets say frugal - and works more or less along a C like expression syntax. And as with C, there are no seperate operators for low/high byte of an address. So

>label needs to become (label >> 8)

while

<label is to be changed to (label & $FF)

(the last can, AFAIK, be obmitted - but keeping it makes it way more readable)

  • 2
    "lets say frugal" - I love understatement :-) – user6464 Nov 7 '18 at 0:43
3

It doesn't appear that crasm has shorthand for getting the high and low byte of a value. You'll have to do it explicitly with the & and >> operators:

High byte:

ldx #pname>>8

Low byte:

ldx #pname&255

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