tniASM is a cross-platform assembler for Z80, R800 and GBZ80 processors. Like AsMSX this assembler uses a syntax a little different than the standard. tniASM is not case sensitive.

Homepage: http://www.tni.nl/products/tniasm.html

Main features:

• Multiple CPU support, even within the same source file
• Customized assembly, use the (pseudo-)instructions YOU like
• Ability to be compatible with other assemblers
• Multi-pass design
• Conditional assembly
• Local label mechanism
• Extensive expression parser with precedence levels
• Source and binary file inclusion
• Nestable block comments
• Output to multiple files
• Update/patch existing files