Hi, Geir;
in the few exploratory experiments I've made, I used David Assembler + Labels (you 'see what you get') and Meindert´s M2KROM.rom. As he says, it is a slightly modified ML ROM but I think M2KROM is better than ML ROM. I also have used MLDL2000 for must of the hardwork because it has plenty of space and you can easily 'plug it in' and save your work in the computer hardisk. Diego´s NoV-series are a 'must have', too, and they occupy 'no space at all'. I have a NoVRAM and a NoV32 along with the two MLDL2000 units.
Anyway, I must confess I began 'stepping into' MCode with HEPAX' HEXEDIT, but HEPAX is a 16K-ROM, and you are mentioning only 4K-ROM, right? For me, it is easy to use if you are a beginner because it shows current memory contents before changing and you see, side by side, what you had and what you are adding . As you get skills, the other tools may give you a different perspective.
If I have to choose, I'd have HEPAX HEXEDIT and David´s ASSM with labels in the same ROM, with a few complementary tools. As I have not yet gone so far in MCoding, I can only think of insertion and copy-paste plus some tools to help building MCODE+USERCODE ROM´s.
Cheers.
Luiz (Brazil)
Edited: 17 Jan 2010, 1:21 p.m.