Microsoft Macro Assembler

Command Line
User manual (since MS is giving MASM away with their DDK's I think its ok to publish this. I can make it private if I hear otherwise)

x86 Instructions@, MASM Instructions, Win32Asm, Win32Prg/API,

Specify values with: (the decimal number 10 is shown on each line as an example)

Binary: y. e.g. 1010y, or b if the radix is not hexadecimal. e.g. .radix 10 1010b. The default Radix is decimal.
Octal: o or q. e.g. 12o, or 12q
Decimal: t e.g.10t , or d if the radix is not hexadecimal. e.g. .radix 8 10d, or just the number if the radix is decimal. e.g. .radix 10 10. The default Radix is decimal.
Hexadecimal: h. e.g. 0Ah. Digits must start with 0...9 so hex numbers starting with A...F must be prepended with a 0.

MASM (the 32bit only version) is available at no cost from Microsoft at:

http://www.microsoft.com/ddk/download/98/BINS_DDK.EXE (2.9 MBytes)
http://www.microsoft.com/ddk/download/98/98SETUP.EXE (1.9 MBytes)
After downloading each file, execute them to extract the files. Then run the setup program. MASM is the ml.exe file in the 98ddk/bin/win98 directory. It is version 6.11d that can be patched to 6.13. This is not the same as purchasing MASM product. The linker is 32 bit and will not create 16-bit DOS programs. To do this, you must have Microsoft's Linker version 5.63 that is available from Microsoft's FTP site: ftp://ftp.microsoft.com/softlib/mslfiles/lnk563.exe. Also, neither the Programmer's Work Bench nor CodeView for debugging are included in the full DDK. Other debuggers are available free of charge from MS.

Or in a much nicer package from MASM32 specifically geared to writing win32 programs in assembler.

MAPSYM is used to convert .MAP files to .SYM symbol files suitable for a debugger.