A simple 6502 disassembler written in Go
The program is intended to be a cheap and cheerful 6502 disassembler for getting output in a format I wanted, and also as an exercise in writing some Go.
Invoke the program by passing the filename of the control file:
./bbc-disgo <filename>
The program uses a "control file" which specifies which file to process as well as a base address and which parts of the file are data. It also specifies the output file and by default the program will look at the output file first to parse comments out in order to re-apply them.
The tool has one required argument, the filename of the control file (see below).
However there are a few options too:
--wipe Don't parse comments out of the target file, ie. wipe all comments (default off)
--column n Look for comment indicator (currently ';') at specified column (default 28)
--dry Write disassembly to stdout rather than the target file (default off)
The control file currently supports 5 commands:
load <string> Specifies the input file (ie. a 6502 binary)
base <address> Set the base address
exec <address> Set the execution address (currently unused)
data <address>,<length> Mark the range at address,length as data
save <string> Set the output file
Numbers (ie address and length) can be decimal or hex (prefixed with 0x). See example-control-file for an example of a control file.
The example control file sets the base to 0x2000 and the first 9 bytes as data. This will output 9 EQUB statements at the start of the file, and treat the rest as code, for example:
2000 00 EQUB 00
2001 01 EQUB 01
2002 13 EQUB 19
2003 F2 EQUB 242
2004 BB EQUB 187
2005 CD EQUB 205
2006 CB EQUB 203
2007 7F EQUB 127
2008 31 EQUB 49
2009 A9 16 LDA #&16
200B 20 EE FF JSR &FFEE
200E A9 02 LDA #&02
2010 20 EE FF JSR &FFEE
...
I pulled out the 6502 definitions from https://github.com/hoglet67/AtomBusMon
6502 reference from https://www.masswerk.at/6502/6502_instruction_set.html