Commit e2d10d7d33dfb1e42808978a06089572efb99677 - SixtyPical

Documentation/notes changes for the 0.13 branch. Chris Pressey 3 years ago

3 changed file(s) with 11 addition(s) and 13 deletion(s). Raw diff Collapse all Expand all

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HISTORY.md less more

0	0	History of SixtyPical
1	1	=====================
	2
	3	0.13
	4	----
	5
	6	* It is a static analysis error if it cannot be proven that a read or write
	7	to a table falls within the defined size of that table.
	8	* The reference analyzer's ability to prove this is currently fairly weak,
	9	but it does exist.
2	10
3	11	0.12
4	12	----

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README.md less more

0	0	SixtyPical
1	1	==========
2	2
3		_Version 0.12. Work-in-progress, everything is subject to change._
	3	_Version 0.13. Work-in-progress, everything is subject to change._
4	4
5	5	SixtyPical is a very low-level programming language, similar to 6502 assembly,
6	6	with static analysis through abstract interpretation.

43	43	This preserves them, so that, semantically, they can be used later even though they
44	44	are trashed inside the block.
45	45
46		### Range checking in the abstract interpretation
47
48		If you copy the address of a buffer (say it is size N) to a pointer, it is valid.
49		If you add a value from 0 to N-1 to the pointer, it is still valid.
50		But if you add a value ≥ N to it, it becomes invalid.
51		This should be tracked in the abstract interpretation.
52		(If only because abstract interpretation is the major point of this project!)
53
54		Range-checking buffers might be too difficult. Range checking tables will be easier.
55		If a value is ANDed with 15, its range must be 0-15, etc.
56
57	46	### Re-order routines and optimize tail-calls to fallthroughs
58	47
59	48	Not because it saves 3 bytes, but because it's a neat trick. Doing it optimally

61	50
62	51	### And at some point...
63	52
	53	* Confirm that `and` can be used to restrict the range of table reads/writes.
64	54	* `low` and `high` address operators - to turn `word` type into `byte`.
65	55	* `const`s that can be used in defining the size of tables, etc.
66	56	* Tests, and implementation, ensuring a routine can be assigned to a vector of "wider" type

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doc/SixtyPical.md less more

26	26
27	27	* T table[N] (N is a power of 2, 1 ≤ N ≤ 256; each entry holds a value
28	28	of type T, where T is `byte`, `word`, or `vector`)
29		* buffer[N] (N entries; each entry is a byte; N is a power of 2, ≤ 64K)
	29	* buffer[N] (N entries; each entry is a byte; 1 ≤ N ≤ 65536)
30	30	* vector T (address of a value of type T; T must be a routine type)
31	31
32	32	### User-defined ###