2.3.1 /Fa, /FA, /Fc and /Fl

Microsoft has extended the C7 /Fa, /Fc, /Fl assembly listing functionality by deprecating /Fc and /Fl, and adding /FA*. The idea is that /Fa names the assembly listing file, and /FA describes what should be in it in addition to the basic assembly text.

/FA takes a string argument, which may contain the letters 'a', 'c', or 's'.

a turns on assembler code representation; it is always implied and is thus a no-op.
c turns on code-bytes, and causes the default extension to be. COD instead of .ASM.
s turns on source code.

CLAXP does not produce an assemblable assembly language source file. Only options that create a .COD file are valid. In effect, the default is .COD because that is the only form of listing supported.

While /Fc and /Fl are still silently accepted, they aren't being documented. Comparison of old and new formats:

old

new

/Fa	/FA and/or /Fa
/Fc	/FAcs (with or without /Fa)
/Fl	/FAc (with or without /Fa)
/Fa{file}	/Fa{file} (with or without /FA)
/Fc{file}	/Fa{file} /FAcs
/Fl{file}	/Fa{file}_/FAs

The overrides are set up in such a way that /Fc, /Fl and /FA are mutually overriding, as are /Fc /Fl and /Fa, while /Fa and /FA do not override.

An alternative description for CLAXP presents the options in two groups. Group 1 is as follows:

Option

Interpretation

/Fa	Error, but treated as if /FAc specified
/Fa{file}	Error, but treated as if /FAc specified
/Fc	Undocumented, but equivalent to /Fa /FAc
/Fc{file}	Undocumented, but equivalent to /Fa{file} /FAc
/Fl	Undocumented, but equivalent to /Fa /FAcs
/Fl{file}	Undocumented, but equivalent to /Fa{file} /FAcs

Group 2 is:

Option

Interpretation

/FA	Error (equivalent to /FAa), but forced to /FAc
/FAa	Error (.ASM), but forced to /FAc (.COD)
/FAc or /FAac	Create listing with code bytes (.COD)
/FAcs or /FAacs	Create listing with code bytes and source (.COD)
/FAs or /FAas	Error (equivalent to /FAas), but forced to /FAcs

/Fa or /Fafile can be added in combination with any of the Group 2 options. The effect is only to determine the name of the file created. Whether the requested file can be created or not is determined solely by the associated /FA form. As noted above, the erroneous forms requesting a .ASM file are forced to request a .COD file with code bytes. So while

/Fa /FAs
/Fa{file} /FA

specify .ASM files, they are treated as if they were written

/Fa /FAcs
/Fa{file} /FAc

respectively.