Just "label" it where you want go back (In this case label the "main" statement). Then jump to the main by use the "label".

Here a example with pseudo-code, cause I've never used TASM / MASM:

@main

   code
   ...

@othercode1

   code
   ...
   jmp @main


@othercode2

   code
   jmp @main

References: It's based on my xp developing a small program in Assembly (NASM), where I needed go and come back to specific statement of the code.