A quick guide to assembling 16-bit programs with TASM

Today I needed to translate some 16-bit DOS assembly to machine code, and I was unable to find an instruction reference that included the binary representation of the commands. Therefore, I did some fiddling around with a DOS version of TASM, which I happened to have laying around.

To assemble a set of instructions, first put it into this structure:

cseg segment 'code'
org 100h

start:
YOUR ASSEMBLER HERE

cseg ends

end start

Save that as a text file, test.asm for instance. Open up your DOS emulator and run this:

tasm test.asm

It produces an object file, which must be linked into a real executable file. For that, there's a different TASM utility:

tlink /t test.obj

You'll then have a COM file which you can open with a hex editor to get your machine code.

I used TASM 3.1 and TLINK 5.1, which are probably available online somewhere.