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Created December 10, 2010 14:49
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lorito braindump
lorito braindump
1 - context is the new interp
- context contains the PC, INSP regs, other stuff as needed (outPC, ehPC, payload, parentContext)
- there's no goto. You assign to the PC
- in a protected context, you can only jump within the segment
- in an unprotected context, you can also jump far away (C function, other segment, etc)
- each context has its own REPR/HOW
- MOP allows security (limited subclass), optimization for platforms (mobile, embedded, PL/X)
- context is the implicit first arg to all ops (we now have 4-arg ops)
- Is there a solution in terms of immutable contexts? (chromatic)
- on invoke and fork, a new context is cloned pointing to the parent
- Context state is COW'd
- there's nothing more global than the context
- this may not be entirely true. There shoud, however be *very* little global state.
- you subclass the context through itself, if the context allows it
- there may be a global thingy for GC
- in a limited context, you can't mess with that kind of thing
2 - for now, we have a fixed number of each register (e.g. 1024)
- later after we have an allocator, we can make this dynamic through the MOP
3 - for now, alloc is an M0 op
4 - look into how Factor does ffi ("alien")
- portable ffi is a hard problem. We don't know the solution.
- we clearly need something. Calling into C-based Parrot internals is vital, external nci is really important
- libffi looks really good, except that it can't do msvc or win64
5 - for int size, there are multiple strategies
- look at the highest bit, optionally autopromote
- the default is the widest supported types
- different M1 ops deal with different types
- Is it possible to use the MOP to deal with ints and still be efficient?
6 - we can use REPR to deal with types for e.g. ffi, efficient storage, user-friendly
7 - CPS works at an M0 level by using Contexts as the continuation
8 - M0 ops are not controlled. Permissions metadata is added at a higher level
- think about something like Java's checked exceptions
- a method has to either declare what it can throw or handle it. Otherwise it won't compile.
9 - Work on Lorito and the MOP can continue independently, though they'll eventually need eachother.
A - Strings and PMCs can share their underlying implementation details, but they still need to have different registers
- Strings are PMCs
what about: segments
what about: messing with the running bytecode
what about: backtraces
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