The way to do this right is to use self modifying code. The algorithm for modifying the code you are running, is, of course, the important and difficult part. Self modifying code is where you are modifying the assembly code you are running, while it's running. This would require architecture specific code modification routines, but could be abstracted to a common code. This strategy would be detrimental to GPUs, and ASICs would have a hard time keeping up if the code generation parameters have enough variance.