ZSM, also known as Z80ASMUK, is a Z80 assembler for CP/M, that outputs HEX files.
I like so much this assembler, so I have recopiled every ZSM version I could find over the Internet and my own disks.
I have even contributed a bit to ZSM with code of my own, mainly patches.
I have developed some companion tools, in order to have a good native development tool chain for the Z80 assembler programming language under the CP/M operating system:
zsmpp: source code preprocessor for the ZSM assembler.bintoasm: converts a binary file into an assembler file for ZSM.hextobin: converts a HEX file into a binary file.hextocom: converts an HEX file into a COM file for CP/M.prl: makes PRL relocatable files from COM files.prntosym: extracts symbols from a PRN file (from ZSM v2.8+) and generates an assembler file for ZSM.rsx: manages RSX files.dump: prints file contents in hexadecimal and ascii format.
Reading the source code of ZSM, it seems there are various custom licenses involved.
Regarding my companion tools, they are under the GPL license.