Command line syntax and options as listed in the 4.0 manual:

        MASM sourcefile [,[objectfile] [,[listingfile] [,[crossreferencefile]]]] [options] [;]

/A- Writes segments in alphabetical order
/S- Writes segments in source-code order
/Bnumber- Sets buffer size
/C- Specifies a cross-reference file
/L- Specifies an assembly-listing file
/D- Creates Pass 1 listing
/Dsymbol- Defines assembler symbol
/Ipath- Set include file search path
/ML- Preserves case sensitivity in names
/MX- Preserves case sensitivity in public and external names
/MU- Converts names to uppercase
/N- Suppresses tables in listing file
/P- Checks for impure code
/R- Creates code for real floating-point instructions
/E- Creates code for emulated floating-point instructions
/T- Suppresses messages for successful assembly
/V- Displays extra statistics to screen
/X- Includes false conditionals in listings
/Z- Displays error lines on screen