Groepaz from the VICE emulator team and the C64 demo group Hitmen just released an updated PDF of 6502 illegal or perhaps more accurately called unintentional opcodes.
I would say this document and the use of illegals are for advanced programmers but they can come in very handy for generating smaller or faster code at times.
Some illegal opcodes can be unstable on certain chips
NMOS 6510 Unintended Opcodes no more secrets (v0.91 – 24/12/16)
San Bergmans has released SB-Assembler 3
Now written in Python 3, runs on Windows, Linux, Max OS.
New Features Of The SB-Assembler 3
- Will now run on Linux, MAC and Windows machines.
- Written in Python3, a modern multi-platform programming language.
- Source files will be included, allowing you to create your own cross overlays.
- Local labels from other global labels can now be accessed.
- Can now generate warning messages where errors would be inappropriate.
- Include source files can now be nested as deep as you like.
- Separate target spaces for code memory, RAM memory and EEPROM memory.
- The .TA directive can be used to map generated code to the ROM address map easily.
- More room, we can now use Giga bytes, in stead of some 550k bytes to do the job.
- As from Version 3.01 label and macro names may also start with an underscore.