This program is used to help automate the program building process. Summary For a while, IBM's and Microsoft's assemblers were the only assembler tools around. Quite a body of source code and experience was built up over time and the MASM tool has continued, if only sporadically, to be updated for the newer processors. Admittedly, there are several serious alternate assemblers you might want to use, these days. NASM is a serious effort at providing a freely available assembler tool and was under active update efforts until a year or two ago.
Appearances are that the effort is far less intense, now.
Also, the GNU tools provide their own quite serious assembler, as well. The problem I have with both of these efforts, and it's no reflection on the folks who have done a magnificent job in meeting their development goals for these products, is that they are quite simply entirely incompatible with a vast expanse of source code, linker tools, and documentation that already exist. If it weren't for the possibility of getting Microsoft's Assembler tools free, now, I'd recommend them. Microsoft doesn't make it easy, of course, but it is surprising to me that they have made this much available at no charge. I'm interested in your experiences with getting and using these tools from Microsoft and also if you have suggestions on how to smooth the process or further enhance the tools.