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WordMaster is a text editor released by MicroPro International in the late 70s and early 80s, commonly regarded as the predecessor to the famous WordStar editor that dominated the PC text processing market in the 1980s. It is much more lightweight than WordStar, and edits only plaintext files. It was written in 8080 assembly language for CP/M.
I have some interest in WordMaster because it is the text editor Tim Paterson used to write 86-DOS. 86-DOS was originally written under Cromemco CDOS, a Z80 CP/M-like operating system, cross-assembled using Tim's 8086 Cross Assembler and written to floppies for testing on the SCP Gazelle using tools that ran under CP/M. WordMaster was the text editor Tim used on Cromemco CDOS, and once 86-DOS was functional enough to self-host, development moved over to the Gazelle. He quickly realised he needed a good editor on the 8086, so he disassembled the copy of WordMaster 1.07 he had, verified that it could be re-assembled to work on the Z80, and translated it to the 8086 using his Z80 to 8086 translator to run under DOS. Tim's DOS port of WordMaster was named SCP Super Editor and was never distributed outside of SCP, as they did not write it.
In 2022, Pat Opalka, one of SCP's employees at that time, shared several dumps of disks from 1981, and some contain the DOS port of WordMaster that was used internally to develop 86-DOS. Pat's copy of SCP Super Editor is customised for his own video card, so it wouldn't run correctly on anything, however, it does provide means of patching for other terminals or graphics cards, just like the original WordMaster. And yes, I also happen to have a copy of WordMaster 1.07 for CP/M from 1980, the same version Tim used.
To get a more authentic experience for my 86-DOS projects, I decided to patch Pat's copy of SCP Super Editor to run under the IBM PC (so that I could run it under regular DOS and DOS emulators), and also patch the original WordMaster for CP/M to work with VT100-compatible terminals, so I could run it under an emulated Cromemco CDOS system. The patches were relatively straightforward, as both WordMaster and Tim's DOS port gave official means of patching and sample patches. You can find my patches in the downloads section at the end of this page.
What I also ended up doing was disassembling the copy of WordMaster 1.07 I have and porting it to DOS, like how Tim did it. Unlike the terminal patches, however, disassembling WordMaster and porting it to DOS was non-trivial. It took a fair bit of effort to get a clean disassembly that would assemble back to the same binary on CP/M, because WordMaster mixed code and data together and relied on subroutines to bump the program counter past the data bytes, which confused all the disassemblers. After the disassembly was done, translating it to 8086 and porting it to DOS was relatively easy, it didn't take me long to match Pat's binaries.
My WordMaster collection:
Page written by Yufeng Gao. Last updated: 2026/03/15.