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assemblyreverse-engineeringx86-16

What happens when you are missing an 8086 missing jump operand?

I'm working on updating some old 8086 assembly code to a more modern system. In my reverse engineering I came across this: 

LINADJ: MOV AX,ENRMAX
SUB AX,LINBND       ;Is energy high enough to decrease power limit?
JLE ENDCYC          ;If not, don't change power limit

The problem is that there is no ENDCYC tag to jump to in this file. What happens when a Jump command doesn't have a valid label to jump to?

Excuse my novice assembly skills, but this label shows up in other closely related files but from what I understand you can't jump from one file to another. So I'm assuming that this jump either becomes a no-op or throws some kind of error.

Solution

  • As mentioned in the comments above. It seems that the final solution is that ENDCYC existed in another piece of code that was linked to the code that I was reverse engineering. After finishing the code under the ENDCYC label it jumps back to the original piece of code. So to answer my own question, yes you can jump from one piece of code to another if they are linked together.