DISCLAIMER: These notes are from the defunct k8 project which precedes SquirrelJME. The notes for SquirrelJME start on 2016/02/26! The k8 project was effectively a Java SE 8 operating system and as such all of the notes are in the context of that scope. That project is no longer my goal as SquirrelJME is the spiritual successor to it.


Appears that the code might end up being convoluted with all of these classes everywhere.


What would work is a generic mutator which any dynarec can use to modify the input byte stream as needed which handles much of things such as the stack. This would help reduce duplicate code that would eventually be placed in all of the dynarecs that would ever be written. Said mutator can be mutable and have capabilities such as managing the stack so operands streams are a bit easier to make. Probably would be best to place it inside of its own package so it can sort of stay out of the way of "narf".


Methods are also a bit more complex than just being a stream of operands. And the various assembly languages are also the same. So there perhaps should be a class which is mutable which describes all of the operations together as a whole. Then passes could operate on the same method bits rather than going through streams, where some passes would require putting it together into a whole bunch of operations anyway. So instead of the stream a huge chunk is returned by the code banks. The current code bank the JavaCodeBank would just be quite literally fill all the operations up first, then walk through them all and figure out the state the method may be in at specific instructions. This could get complex when there are forks (branches around with differing states) so the decoded method would need to handle where states may differ. On large methods with lots of branches all of the information can take up a bunch of memory, so there will need to be some kind of immutable state that can be shared when the state of things is exactly the same. So in this decoded method there would be operations with a possibly unlimited amount of entry states. When a branch is made (the next instruction would be the same branch), states get added and then placed in the decoded method data. If a state was already determined then it is skipped. All local and stack information would be kept variable and unknown and all branches evaluated so that stuff like known constants can be kept from creating tons of states (a for loop with 1,000,000) iterations would proceed to create 1,000,000 different entry states for the loop which is quite too much. The method data can keep track of where it is entered by and the states, so an optimization pass could determine if there is a loop which may be unrolled. Variable maps could also be used to show which variables are modified by each operation.


So to recap, a DecodedMethod which describes all the operations that are performed. The JavaCodeBank will create one and initially seed all the required information as needed. Since the DecodedMethod will be highly RISC it will need to have helper bits that can transform CISC into this RISC.


For SQ, I need a higher level unit information structure that contains the constant unit information as needed so instead of doing complex property data checks it can just grab the annotations semi-directly and make an initial structure based on that.