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MASM Assembly Listing File - interpretation

I've created a listing file of my asm code using commands

cd c:\masm32\bin\
ml.exe /c /Fl"c:\path\file.lst" /Sc "c:\path\file.asm"

The lst file contains three columns: the first one is hex address of specific line, the third one is opcode, but I don't understand the meaning of values in the second column. I think it's called "timing" and the values are someting like: 2 or 10m or even 7m,3. What is the meaning of this numbers, what do they represent?

Solution

  • With the /Sc command-line switch, which generates instruction timings, each line has this syntax:

    offset [[timing]] [[code]]

    The offset is the offset from the beginning of the current code segment. The timing shows the number of cycles the processor needs to execute the instruction. The value of timing reflects the CPU type; for example, specifying the .386 directive produces instruction timings for the 80386 processor. If the statement generates code or data, code shows the numeric value in hexadecimal notation if the value is known at assembly time. If the value is calculated at run time, the assembler indicates what action is necessary to compute the value.

    When assembling under the default .8086 directive, timing includes an effective address value if the instruction accesses memory. The 80186/486 processors do not use effective address values. For more information on effective address timing, see the "Processor" section in the Reference book.

    (source)

    I'm not sure how much I'd trust those timing values unless you're actually going to execute the code on an 80486 or earlier processor.