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Some notes in the README.

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Chris Pressey 2017-12-11 14:18:47 +00:00
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@ -40,36 +40,46 @@ Documentation
TODO
----
Finish the little demo "game" where you can move a block around the screen with
the joystick (i.e. bring it up to par with the original demo game that was written
for SixtyPical)
### Operations on 16 bit values
Compare word (constant or memory location) with memory location or pointer. (Maybe?)
And then write a little demo "game" where you can move a block around the screen with
the joystick.
### `vector table` type
### `low` and `high` address operators
To turn `word` type into `byte`.
### save registers on stack
### Save registers on stack
This preserves them, so that, semantically, they can be used later even though they
are trashed inside the block.
### Range checking in the abstract interpretation
If you copy the address of a buffer (say it is size N) to a pointer, it is valid.
If you add a value from 0 to N-1 to the pointer, it is still valid.
But if you add a value ≥ N to it, it becomes invalid.
This should be tracked in the abstract interpretation.
(If only because abstract interpretation is the major point of this project!)
### And at some point...
* `copy x, [ptr] + y`
* Maybe even `copy [ptra] + y, [ptrb] + y`, which can be compiled to indirect LDA then indirect STA!
* Check that the buffer being read or written to through pointer, appears in approporiate inputs or outputs set.
* `byte table` and `word table` of sizes other than 256
* initialized `byte table` memory locations
* always analyze before executing or compiling, unless told not to
* `trash` instruction.
* `interrupt` routines.
* 6502-mnemonic aliases (`sec`, `clc`)
* other handy aliases (`eq` for `z`, etc.)
* have `copy` instruction able to copy a constant to a user-def mem loc, etc.
* `interrupt` routines -- to indicate that "the supervisor" has stored values on the stack, so we can trash them.
* pre-initialized `word` variables
* error messages that include the line number of the source code
* have `copy` instruction able to copy a byte to a user-def mem loc, etc.
* add absolute addressing in shl/shr, absolute-indexed for add, sub, etc.
* check and disallow recursion.
* automatic tail-call optimization (could be tricky, w/constraints?)