Commit c10e73bdcb7509a094c5aa7b71e238259569de79 - SixtyPical

Merge pull request #8 from catseye/develop-0.12 Develop 0.12 Chris Pressey authored 3 years ago GitHub committed 3 years ago

16 changed file(s) with 877 addition(s) and 376 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	0.12
	4	----
	5
	6	* `copy` is now understood to trash `a`, thus it is not valid to use `a` in `copy`.
	7	To compensate, indirect addressing is supported in `ld` and `st`, for example,
	8	as `ld a, [ptr] + y` and `st a, [ptr] + y`.
	9	* Implements the "union rule for trashes" when analyzing `if` blocks.
	10	* Even if we `goto` another routine, we can't trash an output.
	11	* `static` storage locations local to routines can now be defined within routines.
	12	* Small grammar changes that obviate the need for:
	13	* the parentheses in type expressions like `vector (routine ...) table[256]`
	14	* the `forward` keyword in forward references in source of `copy` instruction
	15	* Fixed bug where `trash` was not marking the location as being virtually altered.
2	16
3	17	0.11
4	18	----

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README.md less more

0	0	SixtyPical
1	1	==========
2	2
3		_Version 0.11. Work-in-progress, everything is subject to change._
	3	_Version 0.12. 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.

38	38	TODO
39	39	----
40	40
41		### `low` and `high` address operators
42
43		To turn `word` type into `byte`.
44
45	41	### Save registers on stack
46	42
47	43	This preserves them, so that, semantically, they can be used later even though they

55	51	This should be tracked in the abstract interpretation.
56	52	(If only because abstract interpretation is the major point of this project!)
57	53
58		### Routine-local static memory locations
	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.
59	56
60		These would not need to appear in the inputs/outputs/trashes sets of the routines
61		that call this routine.
	57	### Re-order routines and optimize tail-calls to fallthroughs
62	58
63		These might be forced to specify an initial value so that they can always be
64		assumed to be meaningful.
65
66		### More modes for `copy`
67
68		* don't allow `copy foo, a` probably. insist on `ld a, foo` for this.
69		* have `copy` instruction able to copy a byte to a user-def mem loc, etc.
70		* `copy x, [ptr] + y`
71		* Maybe even `copy [ptra] + y, [ptrb] + y`, which can be compiled to indirect LDA then indirect STA!
72
73		### Union rule for trashes in `if`
74
75		If one branch trashes {`a`} and the other branch trashes {`b`} then the whole
76		`if` statement trashes {`a`, `b`}.
	59	Not because it saves 3 bytes, but because it's a neat trick. Doing it optimally
	60	is probably NP-complete. But doing it adeuqately is probably not that hard.
77	61
78	62	### And at some point...
79	63
	64	* `low` and `high` address operators - to turn `word` type into `byte`.
	65	* `const`s that can be used in defining the size of tables, etc.
	66	* Tests, and implementation, ensuring a routine can be assigned to a vector of "wider" type
	67	* Related: can we simply view a (small) part of a buffer as a byte table? If not, why not?
80	68	* Check that the buffer being read or written to through pointer, appears in approporiate inputs or outputs set.
	69	(Associate each pointer with the buffer it points into.)
	70	* `static` pointers -- currently not possible because pointers must be zero-page, thus `@`, thus uninitialized.
	71	* Question the value of the "consistent initialization" principle for `if` statement analysis.
81	72	* `interrupt` routines -- to indicate that "the supervisor" has stored values on the stack, so we can trash them.
82		* error messages that include the line number of the source code
83		* add absolute addressing in shl/shr, absolute-indexed for add, sub, etc.
84		* check and disallow recursion.
85		* automatic tail-call optimization (could be tricky, w/constraints?)
86		* re-order routines and optimize tail-calls to fallthroughs
	73	* Error messages that include the line number of the source code.
	74	* Add absolute addressing in shl/shr, absolute-indexed for add, sub, etc.
	75	* Automatic tail-call optimization (could be tricky, w/constraints?)
	76	* Possibly `ld x, [ptr] + y`, possibly `st x, [ptr] + y`.
	77	* Maybe even `copy [ptra] + y, [ptrb] + y`, which can be compiled to indirect LDA then indirect STA!

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doc/Design Goals.md less more

25	25	The intent is not to make it absolutely impossible to make such errors,
26	26	just harder.
27	27
	28	### Things it will Not Do ###
	29
	30	To emphasize the point, the intent is not to make it impossible to make
	31	data-usage (and other) errors, just harder.
	32
	33	Here are some things SixtyPical will not try to detect or prevent you
	34	from doing:
	35
	36	* Check that a vector is initialized before it's called.
	37	* Check that the stack has enough room on it.
	38	* Prevent bad things happening (e.g. clobbering a static storage
	39	location) because of a recursive call. (You can always recursively
	40	call yourself through a vector.)
	41	* Check that reads and writes to a buffer are in bounds. (This may
	42	happen someday, but it's difficult. It's more likely that this
	43	will happen for tables, than for buffers.)
	44
	45	At one point I wanted to do a call-tree analysis to find sets of
	46	routines that would never be called together (i.e. would never be on
	47	the call stack at the same time) and allow any static storage locations
	48	defined within them to occupy the same addresses, i.e. allow storage
	49	to be re-used across these routines. But, in the presence of vectors,
	50	this becomes difficult (see "Prevent bad things happening", above.)
	51	Also, it would usually only save a few bytes of storage space.
	52
28	53	### Some Background ###
29	54
30	55	The ideas in SixtyPical came from a couple of places.

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doc/SixtyPical.md less more

147	147	LDA ($02), Y
148	148	STA ($02), Y
149	149
150		There are extended modes of `copy` for using these types of memory location.
	150	There are extended instruction modes for using these types of memory location.
151	151	See `copy` below, but here is some illustrative example code:
152	152
153	153	copy ^buf, ptr // this is the only way to initialize a pointer

237	237	Some combinations, such as `ld x, y`, are illegal because they do not map to
238	238	underlying opcodes.
239	239
	240	There is another mode of `ld` which reads into `a` indirectly through a pointer.
	241
	242	ld a, [<src-memory-location>] + y
	243
	244	The memory location in this syntax must be a pointer.
	245
	246	This syntax copies the contents of memory at the pointer (offset by the `y`
	247	register) into a register (which must be the `a` register.)
	248
	249	In addition to the constraints above, `y` must be initialized before
	250	this mode is used.
	251
240	252	### st ###
241	253
242	254	st <src-memory-location>, <dest-memory-location> [+ <index-memory-location>]

252	264	changed by this instruction (unless of course dest is a flag.)
253	265
254	266	If and only if dest is a byte table, the index-memory-location must be given.
	267
	268	There is another mode of `st` which write `a` into memory, indirectly through
	269	a pointer.
	270
	271	st a, [<dest-memory-location>] + y
	272
	273	The memory location in this syntax must be a pointer.
	274
	275	This syntax copies the constents of the `a` register into
	276	the contents of memory at the pointer (offset by the `y` register).
	277
	278	In addition to the constraints above, `y` must be initialized before
	279	this mode is used.
255	280
256	281	### copy ###
257	282

511	536	Program ::= {TypeDefn} {Defn} {Routine}.
512	537	TypeDefn::= "typedef" Type Ident<new>.
513	538	Defn ::= Type Ident<new> [Constraints] (":" Literal \| "@" LitWord).
514		Type ::= "(" Type ")" \| TypeExpr ["table" TypeSize].
	539	Type ::= TypeTerm ["table" TypeSize].
515	540	TypeExpr::= "byte"
516	541	\| "word"
517	542	\| "buffer" TypeSize
518	543	\| "pointer"
519		\| "vector" Type
	544	\| "vector" TypeTerm
520	545	\| "routine" Constraints
	546	\| "(" Type ")"
521	547	.
522	548	TypeSize::= "[" LitWord "]".
523	549	Constrnt::= ["inputs" LocExprs] ["outputs" LocExprs] ["trashes" LocExprs].

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eg/new-style-routine.60p less more

	0	// SixtyPical 0.11 introduced a new syntax for defining routines
	1	// (routine was made into a type, and you can now say: define name type.)
	2
	3	typedef routine
	4	inputs x
	5	outputs x
	6	trashes z, n
	7	routine_type
	8
	9	vector routine_type vec
	10
	11	define foo routine_type
	12	{
	13	inc x
	14	}
	15
	16	define main routine
	17	outputs vec
	18	trashes a, z, n
	19	{
	20	copy foo, vec
	21	}

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eg/proto-game.60p less more

30	30	//
31	31
32	32	typedef routine
33		inputs joy2, button_down, press_fire_msg, dispatch_game_state, save_x,
34		actor_pos, pos, new_pos, actor_delta, delta, actor_logic,
	33	inputs joy2, press_fire_msg, dispatch_game_state,
	34	actor_pos, actor_delta, actor_logic,
35	35	screen, screen1, screen2, screen3, screen4, colormap1, colormap2, colormap3, colormap4
36		outputs button_down, dispatch_game_state,
37		actor_pos, pos, new_pos, actor_delta, delta, actor_logic,
	36	outputs dispatch_game_state,
	37	actor_pos, actor_delta, actor_logic,
38	38	screen, screen1, screen2, screen3, screen4, colormap1, colormap2, colormap3, colormap4
39		trashes a, x, y, c, z, n, v, ptr, save_x, compare_target, dispatch_logic
	39	trashes a, x, y, c, z, n, v, pos, new_pos, delta, ptr, dispatch_logic
40	40	game_state_routine
41	41
42	42	//

50	50	typedef routine
51	51	inputs pos, delta, joy2, screen
52	52	outputs pos, delta, new_pos, screen, c
53		trashes a, x, y, z, n, v, ptr, compare_target
	53	trashes a, x, y, z, n, v, ptr
54	54	logic_routine
55	55
56	56	// ----------------------------------------------------------------

86	86	word table[256] actor_delta
87	87	word delta
88	88
89		vector (logic_routine) table[256] actor_logic
	89	vector logic_routine table[256] actor_logic
90	90	vector logic_routine dispatch_logic
91	91
92		byte button_down : 0 // effectively static-local to check_button
93	92	byte table[32] press_fire_msg: "PRESS`FIRE`TO`PLAY"
94
95		byte save_x
96		word compare_target
97	93
98	94	//
99	95	// Points to the routine that implements the current game state.

157	153	// call this routine.
158	154	// Upon return, if carry is set, the button was pressed then released.
159	155
160		routine check_button
161		inputs joy2, button_down
162		outputs c, button_down
	156	define check_button routine
	157	inputs joy2
	158	outputs c
163	159	trashes a, z, n
	160	static byte button_down : 0
164	161	{
165	162	ld a, button_down
166	163	if z {

217	214	add new_pos, delta
218	215	}
219	216
220		routine check_new_position_in_bounds
	217	define check_new_position_in_bounds routine
221	218	inputs new_pos
222	219	outputs c
223		trashes compare_target, a, z, n, v
	220	trashes a, z, n, v
	221	static word compare_target : 0
224	222	{
225	223	copy 1000, compare_target
226	224	st on, c

242	240
243	241	routine init_game
244	242	inputs actor_pos, actor_delta, actor_logic
245		outputs actor_pos, actor_delta, pos, actor_logic
246		trashes a, y, z, n, c, v
	243	outputs actor_pos, actor_delta, actor_logic
	244	trashes pos, a, y, z, n, c, v
247	245	{
248	246	ld y, 0
249	247	copy word 0, pos
250	248	repeat {
251	249	copy pos, actor_pos + y
252	250	copy word 40, actor_delta + y
253		copy forward enemy_logic, actor_logic + y
	251	copy enemy_logic, actor_logic + y
254	252
255	253	st off, c
256	254	add pos, word 7

262	260	ld y, 0
263	261	copy word 0, actor_pos + y
264	262	copy word 0, actor_delta + y
265		copy forward player_logic, actor_logic + y
	263	copy player_logic, actor_logic + y
266	264	}
267	265
268	266	// ----------------------------------------------------------------

283	281	ld y, 0
284	282
285	283	// check collision.
286		copy [ptr] + y, a
	284	ld a, [ptr] + y
287	285	// if "collision" is with your own self, treat it as if it's blank space!
288	286	cmp a, 81
289	287	if z {

306	304	st off, c
307	305	} else {
308	306	st on, c
309		trash n
310		trash a
311		trash z
	307	}
	308
	309	// FIXME these trashes, strictly speaking, probably shouldn't be needed,
	310	// but currently the compiler cares a little too much about values that are
	311	// initialized in one branch of an `if`, but not the other, but are trashed
	312	// at the end of the routine anyway.
	313	trash ptr
	314	trash y
	315	trash v
	316	} else {
	317	st off, c
	318	}
	319	}
	320
	321	define enemy_logic logic_routine
	322	static word compare_target : 0
	323	{
	324	call calculate_new_position
	325	call check_new_position_in_bounds
	326
	327	if c {
	328	copy ^screen, ptr
	329	st off, c
	330	add ptr, new_pos
	331	ld y, 0
	332
	333	// check collision.
	334	ld a, [ptr] + y
	335	// if "collision" is with your own self, treat it as if it's blank space!
	336	cmp a, 82
	337	if z {
	338	ld a, 32
	339	}
	340	cmp a, 32
	341	if z {
	342	copy ^screen, ptr
	343	st off, c
	344	add ptr, pos
	345	copy 32, [ptr] + y
	346
	347	copy new_pos, pos
	348
	349	copy ^screen, ptr
	350	st off, c
	351	add ptr, pos
	352	copy 82, [ptr] + y
	353
	354	st off, c
	355	} else {
	356	st on, c
312	357	}
313	358
314	359	// FIXME these trashes, strictly speaking, probably shouldn't be needed,

317	362	// at the end of the routine anyway.
318	363	trash ptr
319	364	trash y
320		trash a
321		trash v
322		} else {
323		st off, c
324		}
325		}
326
327		define enemy_logic logic_routine
328		{
329		call calculate_new_position
330		call check_new_position_in_bounds
331
332		if c {
333		copy ^screen, ptr
334		st off, c
335		add ptr, new_pos
336		ld y, 0
337
338		// check collision.
339		copy [ptr] + y, a
340		// if "collision" is with your own self, treat it as if it's blank space!
341		cmp a, 82
342		if z {
343		ld a, 32
344		}
345		cmp a, 32
346		if z {
347		copy ^screen, ptr
348		st off, c
349		add ptr, pos
350		copy 32, [ptr] + y
351
352		copy new_pos, pos
353
354		copy ^screen, ptr
355		st off, c
356		add ptr, pos
357		copy 82, [ptr] + y
358
359		st off, c
360		} else {
361		st on, c
362		trash n
363		trash a
364		trash z
365		}
366
367		// FIXME these trashes, strictly speaking, probably shouldn't be needed,
368		// but currently the compiler cares too much about values that are
369		// initialized in one branch of an `if`, but not the other, but trashed
370		// at the end of the routine anyway.
371		trash ptr
372		trash y
373		trash a
374	365	} else {
375	366	copy delta, compare_target
376	367	st on, c

380	371	} else {
381	372	copy $ffd8, delta
382	373	}
383		trash compare_target
384	374	}
385	375
386	376	st off, c

410	400	if c {
411	401	call clear_screen
412	402	call init_game
413		copy forward game_state_play, dispatch_game_state
414
415		// FIXME these trashes, strictly speaking, probably shouldn't be needed,
416		// but currently the compiler cares too much about values that are
417		// initialized in one branch of an `if`, but not the other, but trashed
418		// at the end of the routine anyway.
419		trash a
420		trash n
421		trash z
422		} else {
423		trash y
424		trash c
425		trash v
	403	copy game_state_play, dispatch_game_state
426	404	}
427	405
428	406	goto save_cinv
429	407	}
430	408
431	409	define game_state_play game_state_routine
	410	static byte save_x : 0
432	411	{
433	412	ld x, 0
434	413	repeat {

443	422	if c {
444	423	// Player died! Want no dead! Break out of the loop (this is a bit awkward.)
445	424	call clear_screen
446		copy forward game_state_game_over, dispatch_game_state
	425	copy game_state_game_over, dispatch_game_state
447	426	ld x, 15
448	427	} else {
449	428	ld x, save_x
450		trash c
451	429	}
452	430
453	431	copy pos, actor_pos + x

469	447	call clear_screen
470	448	call init_game
471	449	copy game_state_title_screen, dispatch_game_state
472
473		// FIXME these trashes, strictly speaking, probably shouldn't be needed,
474		// but currently the compiler cares too much about values that are
475		// initialized in one branch of an `if`, but not the other, but trashed
476		// at the end of the routine anyway.
477		trash a
478		trash n
479		trash z
480		} else {
481		trash y
482		trash c
483		trash v
484	450	}
485	451
486	452	goto save_cinv

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eg/vector-table.60p less more

	0	//
	1	// Demonstrates vector tables.
	2	// Prints "AABAB".
	3	//
	4
0	5	vector routine
1	6	trashes a, z, n
2	7	print

30	35	trashes print, a, x, z, n, c
31	36	{
32	37	ld x, 0
33		copy printa, print
34		copy print, vectors + x
	38	copy printa, vectors + x
35	39	inc x
36	40	copy printa, print
37	41	copy print, vectors + x

39	43	copy printb, print
40	44	copy print, vectors + x
41	45	inc x
42		copy printa, print
43		copy print, vectors + x
	46	copy printa, vectors + x
44	47	inc x
45		copy printb, print
46		copy print, vectors + x
47
48		copy printa, print
	48	copy printb, vectors + x
49	49
50	50	ld x, 0
51	51	repeat {

-51

~~eg/vector-table2.60p~~ less more

0		vector routine
1		trashes a, z, n
2		print
3
4		vector (routine
5		trashes a, z, n)
6		table[32] vectors
7
8		routine chrout
9		inputs a
10		trashes a
11		@ 65490
12
13		routine printa
14		trashes a, z, n
15		{
16		ld a, 65
17		call chrout
18		}
19
20		routine printb
21		trashes a, z, n
22		{
23		ld a, 66
24		call chrout
25		}
26
27		routine main
28		inputs vectors
29		outputs vectors
30		trashes print, a, x, z, n, c
31		{
32		ld x, 0
33		copy printa, vectors + x
34		inc x
35		copy printa, vectors + x
36		inc x
37		copy printb, vectors + x
38		inc x
39		copy printa, vectors + x
40		inc x
41		copy printb, vectors + x
42
43		ld x, 0
44		repeat {
45		copy vectors + x, print
46		call print
47		inc x
48		cmp x, 5
49		} until z
50		}

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loadngo.sh less more

0	0	#!/bin/sh
1	1
	2	if [ "X$X64" = "X" ]; then
	3	X64=x64
	4	fi
2	5	SRC=$1
3	6	if [ "X$1" = "X" ]; then
4	7	echo "Usage: ./loadngo.sh <source.60p>"

6	9	fi
7	10	OUT=/tmp/a-out.prg
8	11	bin/sixtypical --traceback --basic-prelude $SRC > $OUT \|\| exit 1
	12	ls -la $OUT
9	13	if [ -e vicerc ]; then
10		x64 -config vicerc $OUT
	14	$X64 -config vicerc $OUT
11	15	else
12		x64 $OUT
	16	$X64 $OUT
13	17	fi
14	18	rm -f $OUT

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-34

src/sixtypical/analyzer.py less more

50	50
51	51	class IncompatibleConstraintsError(ConstraintsError):
52	52	pass
	53
	54
	55	def routine_has_static(routine, ref):
	56	if not hasattr(routine, 'statics'):
	57	return False
	58	for static in routine.statics:
	59	if static.location == ref:
	60	return True
	61	return False
53	62
54	63
55	64	class Context(object):

100	109	c._writeable = set(self._writeable)
101	110	return c
102	111
103		def set_from(self, c):
104		assert c.routines == self.routines
105		assert c.routine == self.routine
106		self._touched = set(c._touched)
107		self._meaningful = set(c._meaningful)
108		self._writeable = set(c._writeable)
109
110	112	def each_meaningful(self):
111	113	for ref in self._meaningful:
112	114	yield ref

118	120	def assert_meaningful(self, refs, *kwargs):
119	121	exception_class = kwargs.get('exception_class', UnmeaningfulReadError)
120	122	for ref in refs:
	123	# statics are always meaningful
	124	if routine_has_static(self.routine, ref):
	125	continue
121	126	if ref.is_constant() or ref in self.routines:
122	127	pass
123	128	elif isinstance(ref, LocationRef):

126	131	if kwargs.get('message'):
127	132	message += ' (%s)' % kwargs['message']
128	133	raise exception_class(message)
	134	elif isinstance(ref, IndexedRef):
	135	self.assert_meaningful(ref.ref, **kwargs)
	136	self.assert_meaningful(ref.index, **kwargs)
129	137	else:
130	138	raise NotImplementedError(ref)
131	139
132	140	def assert_writeable(self, refs, *kwargs):
133	141	exception_class = kwargs.get('exception_class', ForbiddenWriteError)
134	142	for ref in refs:
	143	# statics are always writeable
	144	if routine_has_static(self.routine, ref):
	145	continue
135	146	if ref not in self._writeable:
136	147	message = '%s in %s' % (ref.name, self.routine.name)
137	148	if kwargs.get('message'):

203	214	if routine.block is None:
204	215	# it's an extern, that's fine
205	216	return
206		type = routine.location.type
207		context = Context(self.routines, routine, type.inputs, type.outputs, type.trashes)
	217	type_ = routine.location.type
	218	context = Context(self.routines, routine, type_.inputs, type_.outputs, type_.trashes)
	219
208	220	if self.debug:
209	221	print "at start of routine `{}`:".format(routine.name)
210	222	print context
	223
211	224	self.analyze_block(routine.block, context)
	225	trashed = set(context.each_touched()) - context._meaningful
	226
212	227	if self.debug:
213	228	print "at end of routine `{}`:".format(routine.name)
214	229	print context
	230	print "trashed: ", LocationRef.format_set(trashed)
	231	print "outputs: ", LocationRef.format_set(type_.outputs)
	232	trashed_outputs = type_.outputs & trashed
	233	if trashed_outputs:
	234	print "TRASHED OUTPUTS: ", LocationRef.format_set(trashed_outputs)
	235	print ''
	236	print '-' * 79
	237	print ''
	238
	239	# even if we goto another routine, we can't trash an output.
	240	for ref in trashed:
	241	if ref in type_.outputs:
	242	raise UnmeaningfulOutputError('%s in %s' % (ref.name, routine.name))
	243
215	244	if not self.has_encountered_goto:
216		for ref in type.outputs:
	245	for ref in type_.outputs:
217	246	context.assert_meaningful(ref, exception_class=UnmeaningfulOutputError)
218	247	for ref in context.each_touched():
219		if ref not in type.outputs and ref not in type.trashes:
	248	if ref not in type_.outputs and ref not in type_.trashes and not routine_has_static(routine, ref):
220	249	message = '%s in %s' % (ref.name, routine.name)
221	250	raise ForbiddenWriteError(message)
222	251	self.current_routine = None

235	264	src = instr.src
236	265
237	266	if opcode == 'ld':
238		if instr.index:
239		if TableType.is_a_table_type(src.type, TYPE_BYTE) and dest.type == TYPE_BYTE:
	267	if isinstance(src, IndexedRef):
	268	if TableType.is_a_table_type(src.ref.type, TYPE_BYTE) and dest.type == TYPE_BYTE:
240	269	pass
241	270	else:
242	271	raise TypeMismatchError('%s and %s in %s' %
243		(src.name, dest.name, self.current_routine.name)
	272	(src.ref.name, dest.name, self.current_routine.name)
244	273	)
245		context.assert_meaningful(instr.index)
	274	context.assert_meaningful(src, src.index)
	275	elif isinstance(src, IndirectRef):
	276	# copying this analysis from the matching branch in `copy`, below
	277	if isinstance(src.ref.type, PointerType) and dest.type == TYPE_BYTE:
	278	pass
	279	else:
	280	raise TypeMismatchError((src, dest))
	281	context.assert_meaningful(src.ref, REG_Y)
246	282	elif src.type != dest.type:
247	283	raise TypeMismatchError('%s and %s in %s' %
248	284	(src.name, dest.name, self.current_routine.name)
249	285	)
250		context.assert_meaningful(src)
	286	else:
	287	context.assert_meaningful(src)
251	288	context.set_written(dest, FLAG_Z, FLAG_N)
252	289	elif opcode == 'st':
253		if instr.index:
254		if src.type == TYPE_BYTE and TableType.is_a_table_type(dest.type, TYPE_BYTE):
255		pass
256		else:
257		raise TypeMismatchError((src, dest))
258		context.assert_meaningful(instr.index)
	290	if isinstance(dest, IndexedRef):
	291	if src.type == TYPE_BYTE and TableType.is_a_table_type(dest.ref.type, TYPE_BYTE):
	292	pass
	293	else:
	294	raise TypeMismatchError((src, dest))
	295	context.assert_meaningful(dest.index)
	296	context.set_written(dest.ref)
	297	elif isinstance(dest, IndirectRef):
	298	# copying this analysis from the matching branch in `copy`, below
	299	if isinstance(dest.ref.type, PointerType) and src.type == TYPE_BYTE:
	300	pass
	301	else:
	302	raise TypeMismatchError((src, dest))
	303	context.assert_meaningful(dest.ref, REG_Y)
	304	context.set_written(dest.ref)
259	305	elif src.type != dest.type:
260	306	raise TypeMismatchError('%r and %r in %s' %
261	307	(src, dest, self.current_routine.name)
262	308	)
	309	else:
	310	context.set_written(dest)
263	311	context.assert_meaningful(src)
264		context.set_written(dest)
265	312	elif opcode == 'add':
266	313	context.assert_meaningful(src, dest, FLAG_C)
267	314	if src.type == TYPE_BYTE:

318	365	context.set_touched(ref)
319	366	context.set_unmeaningful(ref)
320	367	elif opcode == 'if':
	368	incoming_meaningful = set(context.each_meaningful())
	369
321	370	context1 = context.clone()
322	371	context2 = context.clone()
323	372	self.analyze_block(instr.block1, context1)
324	373	if instr.block2 is not None:
325	374	self.analyze_block(instr.block2, context2)
	375
	376	outgoing_meaningful = set(context1.each_meaningful()) & set(context2.each_meaningful())
	377	outgoing_trashes = incoming_meaningful - outgoing_meaningful
	378
326	379	# TODO may we need to deal with touched separately here too?
327	380	# probably not; if it wasn't meaningful in the first place, it
328	381	# doesn't really matter if you modified it or not, coming out.
329	382	for ref in context1.each_meaningful():
	383	if ref in outgoing_trashes:
	384	continue
330	385	context2.assert_meaningful(
331	386	ref, exception_class=InconsistentInitializationError,
332	387	message='initialized in block 1 but not in block 2 of `if {}`'.format(src)
333	388	)
334	389	for ref in context2.each_meaningful():
	390	if ref in outgoing_trashes:
	391	continue
335	392	context1.assert_meaningful(
336	393	ref, exception_class=InconsistentInitializationError,
337	394	message='initialized in block 2 but not in block 1 of `if {}`'.format(src)
338	395	)
339		context.set_from(context1)
	396
	397	# merge the contexts. this used to be a method called `set_from`
	398	context._touched = set(context1._touched) \| set(context2._touched)
	399	context._meaningful = outgoing_meaningful
	400	context._writeable = set(context1._writeable) \| set(context2._writeable)
	401
	402	for ref in outgoing_trashes:
	403	context.set_touched(ref)
	404	context.set_unmeaningful(ref)
	405
340	406	elif opcode == 'repeat':
341	407	# it will always be executed at least once, so analyze it having
342	408	# been executed the first time.

351	417	context.assert_meaningful(src)
352	418
353	419	elif opcode == 'copy':
	420	if dest == REG_A:
	421	raise ForbiddenWriteError("{} cannot be used as destination for copy".format(dest))
	422
354	423	# 1. check that their types are compatible
355	424
356	425	if isinstance(src, AddressRef) and isinstance(dest, LocationRef):

410	479	context.set_written(dest.ref)
411	480	elif isinstance(src, IndirectRef) and isinstance(dest, LocationRef):
412	481	context.assert_meaningful(src.ref, REG_Y)
413		# TODO this will need to be more sophisticated. the thing ref points to is touched, as well.
414	482	context.set_written(dest)
415	483	elif isinstance(src, LocationRef) and isinstance(dest, IndexedRef):
416	484	context.assert_meaningful(src, dest.ref, dest.index)

427	495	context.set_written(dest)
428	496
429	497	context.set_touched(REG_A, FLAG_Z, FLAG_N)
430		context.set_unmeaningful(FLAG_Z, FLAG_N)
431
432		# FIXME: this is just to support "copy [foo] + y, a". consider disallowing `a` as something
433		# that can be used in `copy`. should be using `st` or `ld` instead, probably.
434		if dest == REG_A:
435		context.set_touched(REG_A)
436		context.set_written(REG_A)
437		else:
438		context.set_unmeaningful(REG_A)
	498	context.set_unmeaningful(REG_A, FLAG_Z, FLAG_N)
439	499
440	500	elif opcode == 'with-sei':
441	501	self.analyze_block(instr.block, context)

460	520
461	521	self.has_encountered_goto = True
462	522	elif opcode == 'trash':
	523	context.set_touched(instr.dest)
463	524	context.set_unmeaningful(instr.dest)
464	525	else:
465	526	raise NotImplementedError(opcode)

+124

-92

src/sixtypical/compiler.py less more

27	27	class Compiler(object):
28	28	def __init__(self, emitter):
29	29	self.emitter = emitter
30		self.routines = {}
31		self.labels = {}
32		self.trampolines = {} # Location -> Label
	30	self.routines = {} # routine.name -> Routine
	31	self.routine_statics = {} # routine.name -> { static.name -> Label }
	32	self.labels = {} # global.name -> Label ("global" includes routines)
	33	self.trampolines = {} # Location -> Label
	34	self.current_routine = None
33	35
34	36	# helper methods
35	37

41	43	else:
42	44	raise NotImplementedError(index)
43	45
	46	def compute_length_of_defn(self, defn):
	47	length = None
	48	type_ = defn.location.type
	49	if type_ == TYPE_BYTE:
	50	length = 1
	51	elif type_ == TYPE_WORD or isinstance(type_, (PointerType, VectorType)):
	52	length = 2
	53	elif isinstance(type_, TableType):
	54	length = type_.size * (1 if type_.of_type == TYPE_BYTE else 2)
	55	elif isinstance(type_, BufferType):
	56	length = type_.size
	57	if length is None:
	58	raise NotImplementedError("Need size for type {}".format(type_))
	59	return length
	60
	61	def get_label(self, name):
	62	if self.current_routine:
	63	static_label = self.routine_statics.get(self.current_routine.name, {}).get(name)
	64	if static_label:
	65	return static_label
	66	return self.labels[name]
	67
44	68	# visitor methods
45	69
46	70	def compile_program(self, program):
47	71	assert isinstance(program, Program)
48	72
	73	defn_labels = []
	74
49	75	for defn in program.defns:
50		# compute length of memory pointed to. this is awful.
51		length = None
52		type_ = defn.location.type
53		if type_ == TYPE_BYTE:
54		length = 1
55		elif type_ == TYPE_WORD or isinstance(type_, (PointerType, VectorType)):
56		length = 2
57		elif isinstance(type_, TableType):
58		length = type_.size * (1 if type_.of_type == TYPE_BYTE else 2)
59		elif isinstance(type_, BufferType):
60		length = type_.size
61		if length is None:
62		raise NotImplementedError("Need size for type {}".format(type_))
63		self.labels[defn.name] = Label(defn.name, addr=defn.addr, length=length)
	76	length = self.compute_length_of_defn(defn)
	77	label = Label(defn.name, addr=defn.addr, length=length)
	78	self.labels[defn.name] = label
	79	defn_labels.append((defn, label))
64	80
65	81	for routine in program.routines:
66	82	self.routines[routine.name] = routine

69	85	label.set_addr(routine.addr)
70	86	self.labels[routine.name] = label
71	87
	88	if hasattr(routine, 'statics'):
	89	static_labels = {}
	90	for defn in routine.statics:
	91	length = self.compute_length_of_defn(defn)
	92	label = Label(defn.name, addr=defn.addr, length=length)
	93	static_labels[defn.name] = label
	94	defn_labels.append((defn, label))
	95	self.routine_statics[routine.name] = static_labels
	96
72	97	self.compile_routine(self.routines['main'])
73	98	for routine in program.routines:
74	99	if routine.name != 'main':

76	101
77	102	for location, label in self.trampolines.iteritems():
78	103	self.emitter.resolve_label(label)
79		self.emitter.emit(JMP(Indirect(self.labels[location.name])))
	104	self.emitter.emit(JMP(Indirect(self.get_label(location.name))))
80	105	self.emitter.emit(RTS())
81	106
82	107	# initialized data
83		for defn in program.defns:
	108	for defn, label in defn_labels:
84	109	if defn.initial is not None:
85		label = self.labels[defn.name]
86	110	initial_data = None
87	111	type_ = defn.location.type
88	112	if type_ == TYPE_BYTE:

98	122	self.emitter.emit(initial_data)
99	123
100	124	# uninitialized, "BSS" data
101		for defn in program.defns:
	125	for defn, label in defn_labels:
102	126	if defn.initial is None and defn.addr is None:
103		label = self.labels[defn.name]
104	127	self.emitter.resolve_bss_label(label)
105	128
106
107	129	def compile_routine(self, routine):
	130	self.current_routine = routine
108	131	assert isinstance(routine, Routine)
109	132	if routine.block:
110		self.emitter.resolve_label(self.labels[routine.name])
	133	self.emitter.resolve_label(self.get_label(routine.name))
111	134	self.compile_block(routine.block)
112	135	self.emitter.emit(RTS())
	136	self.current_routine = None
113	137
114	138	def compile_block(self, block):
115	139	assert isinstance(block, Block)

130	154	self.emitter.emit(TYA())
131	155	elif isinstance(src, ConstantRef):
132	156	self.emitter.emit(LDA(Immediate(Byte(src.value))))
133		elif instr.index == REG_X:
134		self.emitter.emit(LDA(AbsoluteX(self.labels[src.name])))
135		elif instr.index == REG_Y:
136		self.emitter.emit(LDA(AbsoluteY(self.labels[src.name])))
137		else:
138		self.emitter.emit(LDA(Absolute(self.labels[src.name])))
	157	elif isinstance(src, IndexedRef) and src.index == REG_X:
	158	self.emitter.emit(LDA(AbsoluteX(self.get_label(src.ref.name))))
	159	elif isinstance(src, IndexedRef) and src.index == REG_Y:
	160	self.emitter.emit(LDA(AbsoluteY(self.get_label(src.ref.name))))
	161	elif isinstance(src, IndirectRef) and isinstance(src.ref.type, PointerType):
	162	self.emitter.emit(LDA(IndirectY(self.get_label(src.ref.name))))
	163	else:
	164	self.emitter.emit(LDA(Absolute(self.get_label(src.name))))
139	165	elif dest == REG_X:
140	166	if src == REG_A:
141	167	self.emitter.emit(TAX())
142	168	elif isinstance(src, ConstantRef):
143	169	self.emitter.emit(LDX(Immediate(Byte(src.value))))
144		elif instr.index == REG_Y:
145		self.emitter.emit(LDX(AbsoluteY(self.labels[src.name])))
146		else:
147		self.emitter.emit(LDX(Absolute(self.labels[src.name])))
	170	elif isinstance(src, IndexedRef) and src.index == REG_Y:
	171	self.emitter.emit(LDX(AbsoluteY(self.get_label(src.ref.name))))
	172	else:
	173	self.emitter.emit(LDX(Absolute(self.get_label(src.name))))
148	174	elif dest == REG_Y:
149	175	if src == REG_A:
150	176	self.emitter.emit(TAY())
151	177	elif isinstance(src, ConstantRef):
152	178	self.emitter.emit(LDY(Immediate(Byte(src.value))))
153		elif instr.index == REG_X:
154		self.emitter.emit(LDY(AbsoluteX(self.labels[src.name])))
155		else:
156		self.emitter.emit(LDY(Absolute(self.labels[src.name])))
	179	elif isinstance(src, IndexedRef) and src.index == REG_X:
	180	self.emitter.emit(LDY(AbsoluteX(self.get_label(src.ref.name))))
	181	else:
	182	self.emitter.emit(LDY(Absolute(self.get_label(src.name))))
157	183	else:
158	184	raise UnsupportedOpcodeError(instr)
159	185	elif opcode == 'st':

167	193	REG_X: STX,
168	194	REG_Y: STY
169	195	}.get(src, None)
170		mode_cls = {
171		REG_X: AbsoluteX,
172		REG_Y: AbsoluteY,
173		None: Absolute
174		}.get(instr.index, None)
	196
	197	if isinstance(dest, IndexedRef):
	198	mode_cls = {
	199	REG_X: AbsoluteX,
	200	REG_Y: AbsoluteY,
	201	}[dest.index]
	202	label = self.get_label(dest.ref.name)
	203	elif isinstance(dest, IndirectRef) and isinstance(dest.ref.type, PointerType):
	204	mode_cls = IndirectY
	205	label = self.get_label(dest.ref.name)
	206	else:
	207	mode_cls = Absolute
	208	label = self.get_label(dest.name)
	209
175	210	if op_cls is None or mode_cls is None:
176	211	raise UnsupportedOpcodeError(instr)
177		self.emitter.emit(op_cls(mode_cls(self.labels[dest.name])))
	212	self.emitter.emit(op_cls(mode_cls(label)))
178	213	elif opcode == 'add':
179	214	if dest == REG_A:
180	215	if isinstance(src, ConstantRef):
181	216	self.emitter.emit(ADC(Immediate(Byte(src.value))))
182	217	else:
183		self.emitter.emit(ADC(Absolute(self.labels[src.name])))
	218	self.emitter.emit(ADC(Absolute(self.get_label(src.name))))
184	219	elif isinstance(dest, LocationRef) and src.type == TYPE_WORD and dest.type == TYPE_WORD:
185	220	if isinstance(src, ConstantRef):
186		dest_label = self.labels[dest.name]
	221	dest_label = self.get_label(dest.name)
187	222	self.emitter.emit(LDA(Absolute(dest_label)))
188	223	self.emitter.emit(ADC(Immediate(Byte(src.low_byte()))))
189	224	self.emitter.emit(STA(Absolute(dest_label)))

191	226	self.emitter.emit(ADC(Immediate(Byte(src.high_byte()))))
192	227	self.emitter.emit(STA(Absolute(Offset(dest_label, 1))))
193	228	elif isinstance(src, LocationRef):
194		src_label = self.labels[src.name]
195		dest_label = self.labels[dest.name]
	229	src_label = self.get_label(src.name)
	230	dest_label = self.get_label(dest.name)
196	231	self.emitter.emit(LDA(Absolute(dest_label)))
197	232	self.emitter.emit(ADC(Absolute(src_label)))
198	233	self.emitter.emit(STA(Absolute(dest_label)))

203	238	raise UnsupportedOpcodeError(instr)
204	239	elif isinstance(dest, LocationRef) and src.type == TYPE_WORD and isinstance(dest.type, PointerType):
205	240	if isinstance(src, ConstantRef):
206		dest_label = self.labels[dest.name]
	241	dest_label = self.get_label(dest.name)
207	242	self.emitter.emit(LDA(ZeroPage(dest_label)))
208	243	self.emitter.emit(ADC(Immediate(Byte(src.low_byte()))))
209	244	self.emitter.emit(STA(ZeroPage(dest_label)))

211	246	self.emitter.emit(ADC(Immediate(Byte(src.high_byte()))))
212	247	self.emitter.emit(STA(ZeroPage(Offset(dest_label, 1))))
213	248	elif isinstance(src, LocationRef):
214		src_label = self.labels[src.name]
215		dest_label = self.labels[dest.name]
	249	src_label = self.get_label(src.name)
	250	dest_label = self.get_label(dest.name)
216	251	self.emitter.emit(LDA(ZeroPage(dest_label)))
217	252	self.emitter.emit(ADC(Absolute(src_label)))
218	253	self.emitter.emit(STA(ZeroPage(dest_label)))

228	263	if isinstance(src, ConstantRef):
229	264	self.emitter.emit(SBC(Immediate(Byte(src.value))))
230	265	else:
231		self.emitter.emit(SBC(Absolute(self.labels[src.name])))
	266	self.emitter.emit(SBC(Absolute(self.get_label(src.name))))
232	267	elif isinstance(dest, LocationRef) and src.type == TYPE_WORD and dest.type == TYPE_WORD:
233	268	if isinstance(src, ConstantRef):
234		dest_label = self.labels[dest.name]
	269	dest_label = self.get_label(dest.name)
235	270	self.emitter.emit(LDA(Absolute(dest_label)))
236	271	self.emitter.emit(SBC(Immediate(Byte(src.low_byte()))))
237	272	self.emitter.emit(STA(Absolute(dest_label)))

239	274	self.emitter.emit(SBC(Immediate(Byte(src.high_byte()))))
240	275	self.emitter.emit(STA(Absolute(Offset(dest_label, 1))))
241	276	elif isinstance(src, LocationRef):
242		src_label = self.labels[src.name]
243		dest_label = self.labels[dest.name]
	277	src_label = self.get_label(src.name)
	278	dest_label = self.get_label(dest.name)
244	279	self.emitter.emit(LDA(Absolute(dest_label)))
245	280	self.emitter.emit(SBC(Absolute(src_label)))
246	281	self.emitter.emit(STA(Absolute(dest_label)))

257	292	elif dest == REG_Y:
258	293	self.emitter.emit(INY())
259	294	else:
260		self.emitter.emit(INC(Absolute(self.labels[dest.name])))
	295	self.emitter.emit(INC(Absolute(self.get_label(dest.name))))
261	296	elif opcode == 'dec':
262	297	if dest == REG_X:
263	298	self.emitter.emit(DEX())
264	299	elif dest == REG_Y:
265	300	self.emitter.emit(DEY())
266	301	else:
267		self.emitter.emit(DEC(Absolute(self.labels[dest.name])))
	302	self.emitter.emit(DEC(Absolute(self.get_label(dest.name))))
268	303	elif opcode == 'cmp':
269	304	cls = {
270	305	'a': CMP,

276	311	if isinstance(src, ConstantRef):
277	312	self.emitter.emit(cls(Immediate(Byte(src.value))))
278	313	else:
279		self.emitter.emit(cls(Absolute(self.labels[src.name])))
	314	self.emitter.emit(cls(Absolute(self.get_label(src.name))))
280	315	elif opcode in ('and', 'or', 'xor',):
281	316	cls = {
282	317	'and': AND,

287	322	if isinstance(src, ConstantRef):
288	323	self.emitter.emit(cls(Immediate(Byte(src.value))))
289	324	else:
290		self.emitter.emit(cls(Absolute(self.labels[src.name])))
	325	self.emitter.emit(cls(Absolute(self.get_label(src.name))))
291	326	else:
292	327	raise UnsupportedOpcodeError(instr)
293	328	elif opcode in ('shl', 'shr'):

301	336	raise UnsupportedOpcodeError(instr)
302	337	elif opcode == 'call':
303	338	location = instr.location
304		label = self.labels[instr.location.name]
	339	label = self.get_label(instr.location.name)
305	340	if isinstance(location.type, RoutineType):
306	341	self.emitter.emit(JSR(Absolute(label)))
307	342	elif isinstance(location.type, VectorType):

313	348	raise NotImplementedError
314	349	elif opcode == 'goto':
315	350	location = instr.location
316		label = self.labels[instr.location.name]
	351	label = self.get_label(instr.location.name)
317	352	if isinstance(location.type, RoutineType):
318	353	self.emitter.emit(JMP(Absolute(label)))
319	354	elif isinstance(location.type, VectorType):

371	406	if isinstance(src, (LocationRef, ConstantRef)) and isinstance(dest, IndirectRef):
372	407	if src.type == TYPE_BYTE and isinstance(dest.ref.type, PointerType):
373	408	if isinstance(src, ConstantRef):
374		dest_label = self.labels[dest.ref.name]
	409	dest_label = self.get_label(dest.ref.name)
375	410	self.emitter.emit(LDA(Immediate(Byte(src.value))))
376	411	self.emitter.emit(STA(IndirectY(dest_label)))
377	412	elif isinstance(src, LocationRef):
378		src_label = self.labels[src.name]
379		dest_label = self.labels[dest.ref.name]
	413	src_label = self.get_label(src.name)
	414	dest_label = self.get_label(dest.ref.name)
380	415	self.emitter.emit(LDA(Absolute(src_label)))
381	416	self.emitter.emit(STA(IndirectY(dest_label)))
382	417	else:

384	419	else:
385	420	raise NotImplementedError((src, dest))
386	421	elif isinstance(src, IndirectRef) and isinstance(dest, LocationRef):
387		if dest == REG_A and isinstance(src.ref.type, PointerType):
388		src_label = self.labels[src.ref.name]
389		self.emitter.emit(LDA(IndirectY(src_label)))
390		elif dest.type == TYPE_BYTE and isinstance(src.ref.type, PointerType):
391		src_label = self.labels[src.ref.name]
392		dest_label = self.labels[dest.name]
	422	if dest.type == TYPE_BYTE and isinstance(src.ref.type, PointerType):
	423	src_label = self.get_label(src.ref.name)
	424	dest_label = self.get_label(dest.name)
393	425	self.emitter.emit(LDA(IndirectY(src_label)))
394	426	self.emitter.emit(STA(Absolute(dest_label)))
395	427	else:
396	428	raise NotImplementedError((src, dest))
397	429	elif isinstance(src, AddressRef) and isinstance(dest, LocationRef) and \
398	430	isinstance(src.ref.type, BufferType) and isinstance(dest.type, PointerType):
399		src_label = self.labels[src.ref.name]
400		dest_label = self.labels[dest.name]
	431	src_label = self.get_label(src.ref.name)
	432	dest_label = self.get_label(dest.name)
401	433	self.emitter.emit(LDA(Immediate(HighAddressByte(src_label))))
402	434	self.emitter.emit(STA(ZeroPage(dest_label)))
403	435	self.emitter.emit(LDA(Immediate(LowAddressByte(src_label))))
404	436	self.emitter.emit(STA(ZeroPage(Offset(dest_label, 1))))
405	437	elif isinstance(src, LocationRef) and isinstance(dest, IndexedRef):
406	438	if src.type == TYPE_WORD and TableType.is_a_table_type(dest.ref.type, TYPE_WORD):
407		src_label = self.labels[src.name]
408		dest_label = self.labels[dest.ref.name]
	439	src_label = self.get_label(src.name)
	440	dest_label = self.get_label(dest.ref.name)
409	441	self.emitter.emit(LDA(Absolute(src_label)))
410	442	self.emitter.emit(STA(self.addressing_mode_for_index(dest.index)(dest_label)))
411	443	self.emitter.emit(LDA(Absolute(Offset(src_label, 1))))
412	444	self.emitter.emit(STA(self.addressing_mode_for_index(dest.index)(Offset(dest_label, 256))))
413	445	elif isinstance(src.type, VectorType) and isinstance(dest.ref.type, TableType) and isinstance(dest.ref.type.of_type, VectorType):
414	446	# FIXME this is the exact same as above - can this be simplified?
415		src_label = self.labels[src.name]
416		dest_label = self.labels[dest.ref.name]
	447	src_label = self.get_label(src.name)
	448	dest_label = self.get_label(dest.ref.name)
417	449	self.emitter.emit(LDA(Absolute(src_label)))
418	450	self.emitter.emit(STA(self.addressing_mode_for_index(dest.index)(dest_label)))
419	451	self.emitter.emit(LDA(Absolute(Offset(src_label, 1))))
420	452	self.emitter.emit(STA(self.addressing_mode_for_index(dest.index)(Offset(dest_label, 256))))
421	453	elif isinstance(src.type, RoutineType) and isinstance(dest.ref.type, TableType) and isinstance(dest.ref.type.of_type, VectorType):
422		src_label = self.labels[src.name]
423		dest_label = self.labels[dest.ref.name]
	454	src_label = self.get_label(src.name)
	455	dest_label = self.get_label(dest.ref.name)
424	456	self.emitter.emit(LDA(Immediate(HighAddressByte(src_label))))
425	457	self.emitter.emit(STA(self.addressing_mode_for_index(dest.index)(dest_label)))
426	458	self.emitter.emit(LDA(Immediate(LowAddressByte(src_label))))

429	461	raise NotImplementedError
430	462	elif isinstance(src, ConstantRef) and isinstance(dest, IndexedRef):
431	463	if src.type == TYPE_WORD and TableType.is_a_table_type(dest.ref.type, TYPE_WORD):
432		dest_label = self.labels[dest.ref.name]
	464	dest_label = self.get_label(dest.ref.name)
433	465	self.emitter.emit(LDA(Immediate(Byte(src.low_byte()))))
434	466	self.emitter.emit(STA(self.addressing_mode_for_index(dest.index)(dest_label)))
435	467	self.emitter.emit(LDA(Immediate(Byte(src.high_byte()))))

438	470	raise NotImplementedError
439	471	elif isinstance(src, IndexedRef) and isinstance(dest, LocationRef):
440	472	if TableType.is_a_table_type(src.ref.type, TYPE_WORD) and dest.type == TYPE_WORD:
441		src_label = self.labels[src.ref.name]
442		dest_label = self.labels[dest.name]
	473	src_label = self.get_label(src.ref.name)
	474	dest_label = self.get_label(dest.name)
443	475	self.emitter.emit(LDA(self.addressing_mode_for_index(src.index)(src_label)))
444	476	self.emitter.emit(STA(Absolute(dest_label)))
445	477	self.emitter.emit(LDA(self.addressing_mode_for_index(src.index)(Offset(src_label, 256))))
446	478	self.emitter.emit(STA(Absolute(Offset(dest_label, 1))))
447	479	elif isinstance(dest.type, VectorType) and isinstance(src.ref.type, TableType) and isinstance(src.ref.type.of_type, VectorType):
448	480	# FIXME this is the exact same as above - can this be simplified?
449		src_label = self.labels[src.ref.name]
450		dest_label = self.labels[dest.name]
	481	src_label = self.get_label(src.ref.name)
	482	dest_label = self.get_label(dest.name)
451	483	self.emitter.emit(LDA(self.addressing_mode_for_index(src.index)(src_label)))
452	484	self.emitter.emit(STA(Absolute(dest_label)))
453	485	self.emitter.emit(LDA(self.addressing_mode_for_index(src.index)(Offset(src_label, 256))))

461	493	if isinstance(src, ConstantRef):
462	494	raise NotImplementedError
463	495	else:
464		src_label = self.labels[src.name]
465		dest_label = self.labels[dest.name]
	496	src_label = self.get_label(src.name)
	497	dest_label = self.get_label(dest.name)
466	498	self.emitter.emit(LDA(Absolute(src_label)))
467	499	self.emitter.emit(STA(Absolute(dest_label)))
468	500	elif src.type == TYPE_WORD and dest.type == TYPE_WORD:
469	501	if isinstance(src, ConstantRef):
470		dest_label = self.labels[dest.name]
	502	dest_label = self.get_label(dest.name)
471	503	self.emitter.emit(LDA(Immediate(Byte(src.low_byte()))))
472	504	self.emitter.emit(STA(Absolute(dest_label)))
473	505	self.emitter.emit(LDA(Immediate(Byte(src.high_byte()))))
474	506	self.emitter.emit(STA(Absolute(Offset(dest_label, 1))))
475	507	else:
476		src_label = self.labels[src.name]
477		dest_label = self.labels[dest.name]
	508	src_label = self.get_label(src.name)
	509	dest_label = self.get_label(dest.name)
478	510	self.emitter.emit(LDA(Absolute(src_label)))
479	511	self.emitter.emit(STA(Absolute(dest_label)))
480	512	self.emitter.emit(LDA(Absolute(Offset(src_label, 1))))
481	513	self.emitter.emit(STA(Absolute(Offset(dest_label, 1))))
482	514	elif isinstance(src.type, VectorType) and isinstance(dest.type, VectorType):
483		src_label = self.labels[src.name]
484		dest_label = self.labels[dest.name]
	515	src_label = self.get_label(src.name)
	516	dest_label = self.get_label(dest.name)
485	517	self.emitter.emit(LDA(Absolute(src_label)))
486	518	self.emitter.emit(STA(Absolute(dest_label)))
487	519	self.emitter.emit(LDA(Absolute(Offset(src_label, 1))))
488	520	self.emitter.emit(STA(Absolute(Offset(dest_label, 1))))
489	521	elif isinstance(src.type, RoutineType) and isinstance(dest.type, VectorType):
490		src_label = self.labels[src.name]
491		dest_label = self.labels[dest.name]
	522	src_label = self.get_label(src.name)
	523	dest_label = self.get_label(dest.name)
492	524	self.emitter.emit(LDA(Immediate(HighAddressByte(src_label))))
493	525	self.emitter.emit(STA(Absolute(dest_label)))
494	526	self.emitter.emit(LDA(Immediate(LowAddressByte(src_label))))

-1

src/sixtypical/model.py less more

144	144	# just to be sure.
145	145	equal = isinstance(other, self.__class__) and other.name == self.name
146	146	if equal:
147		assert other.type == self.type
	147	assert other.type == self.type, repr((self, other))
148	148	return equal
149	149
150	150	def __hash__(self):

+80

-27

src/sixtypical/parser.py less more

13	13	self.ast_node = ast_node
14	14	self.model = model
15	15
	16	def __repr__(self):
	17	return "%s(%r, %r)" % (self.__class__.__name__, self.ast_node, self.model)
	18
16	19
17	20	class Parser(object):
18	21	def __init__(self, text):
19	22	self.scanner = Scanner(text)
20		self.symbols = {} # token -> SymEntry
21		self.typedefs = {} # token -> Type AST
	23	self.symbols = {} # token -> SymEntry
	24	self.current_statics = {} # token -> SymEntry
	25	self.typedefs = {} # token -> Type AST
22	26	for token in ('a', 'x', 'y'):
23	27	self.symbols[token] = SymEntry(None, LocationRef(TYPE_BYTE, token))
24	28	for token in ('c', 'z', 'n', 'v'):
25	29	self.symbols[token] = SymEntry(None, LocationRef(TYPE_BIT, token))
26	30	self.backpatch_instrs = []
27	31
	32	def soft_lookup(self, name):
	33	if name in self.current_statics:
	34	return self.current_statics[name].model
	35	if name in self.symbols:
	36	return self.symbols[name].model
	37	return None
	38
28	39	def lookup(self, name):
29		if name not in self.symbols:
	40	model = self.soft_lookup(name)
	41	if model is None:
30	42	raise SyntaxError('Undefined symbol "%s"' % name)
31		return self.symbols[name].model
	43	return model
32	44
33	45	# --- grammar productions
34	46

129	141	return size
130	142
131	143	def defn_type(self):
	144	type_ = self.defn_type_term()
	145
	146	if self.scanner.consume('table'):
	147	size = self.defn_size()
	148	type_ = TableType(type_, size)
	149
	150	return type_
	151
	152	def defn_type_term(self):
132	153	type_ = None
133	154
134	155	if self.scanner.consume('('):

141	162	elif self.scanner.consume('word'):
142	163	type_ = TYPE_WORD
143	164	elif self.scanner.consume('vector'):
144		type_ = self.defn_type()
	165	type_ = self.defn_type_term()
145	166	if not isinstance(type_, RoutineType):
146	167	raise SyntaxError("Vectors can only be of a routine, not %r" % type_)
147	168	type_ = VectorType(type_)

160	181	raise SyntaxError("Undefined type '%s'" % type_name)
161	182	type_ = self.typedefs[type_name]
162	183
163		if self.scanner.consume('table'):
164		size = self.defn_size()
165		type_ = TableType(type_, size)
166
167	184	return type_
168	185
169	186	def defn_name(self):

208	225	type_ = self.defn_type()
209	226	if not isinstance(type_, RoutineType):
210	227	raise SyntaxError("Can only define a routine, not %r" % type_)
	228	statics = []
211	229	if self.scanner.consume('@'):
212	230	self.scanner.check_type('integer literal')
213	231	block = None
214	232	addr = int(self.scanner.token)
215	233	self.scanner.scan()
216	234	else:
	235	statics = self.statics()
	236
	237	self.current_statics = self.compose_statics_dict(statics)
217	238	block = self.block()
	239	self.current_statics = {}
	240
218	241	addr = None
219	242	location = LocationRef(type_, name)
220	243	return Routine(
221	244	name=name, block=block, addr=addr,
222		location=location
	245	location=location, statics=statics
223	246	)
	247
	248	def compose_statics_dict(self, statics):
	249	c = {}
	250	for defn in statics:
	251	name = defn.name
	252	if name in self.symbols or name in self.current_statics:
	253	raise SyntaxError('Symbol "%s" already declared' % name)
	254	c[name] = SymEntry(defn, defn.location)
	255	return c
224	256
225	257	def labels(self):
226	258	accum = []

243	275	accum.append(self.locexpr())
244	276	return accum
245	277
246		def locexpr(self):
	278	def locexpr(self, forward=False):
247	279	if self.scanner.token in ('on', 'off'):
248	280	loc = ConstantRef(TYPE_BIT, 1 if self.scanner.token == 'on' else 0)
249	281	self.scanner.scan()

258	290	loc = ConstantRef(TYPE_WORD, int(self.scanner.token))
259	291	self.scanner.scan()
260	292	return loc
	293	elif forward:
	294	name = self.scanner.token
	295	self.scanner.scan()
	296	loc = self.soft_lookup(name)
	297	if loc is not None:
	298	return loc
	299	else:
	300	return name
261	301	else:
262	302	loc = self.lookup(self.scanner.token)
263	303	self.scanner.scan()
264	304	return loc
265	305
266		def indlocexpr(self):
267		if self.scanner.consume('forward'):
268		return self.label()
269		elif self.scanner.consume('['):
	306	def indlocexpr(self, forward=False):
	307	if self.scanner.consume('['):
270	308	loc = self.locexpr()
271	309	self.scanner.expect(']')
272	310	self.scanner.expect('+')

276	314	loc = self.locexpr()
277	315	return AddressRef(loc)
278	316	else:
279		loc = self.locexpr()
280		index = None
281		if self.scanner.consume('+'):
282		index = self.locexpr()
283		loc = IndexedRef(loc, index)
	317	loc = self.locexpr(forward=forward)
	318	if not isinstance(loc, basestring):
	319	index = None
	320	if self.scanner.consume('+'):
	321	index = self.locexpr()
	322	loc = IndexedRef(loc, index)
284	323	return loc
	324
	325	def statics(self):
	326	defns = []
	327	while self.scanner.consume('static'):
	328	defn = self.defn()
	329	if defn.initial is None:
	330	raise SyntaxError("Static definition {} must have initial value".format(defn))
	331	defns.append(defn)
	332	return defns
285	333
286	334	def block(self):
287	335	instrs = []

315	363	self.scanner.expect('forever')
316	364	return Instr(opcode='repeat', dest=None, src=src,
317	365	block=block, inverted=inverted)
318		elif self.scanner.token in ("ld", "add", "sub", "cmp", "and", "or", "xor"):
	366	elif self.scanner.token in ("ld",):
	367	# the same as add, sub, cmp etc below, except supports an indlocexpr for the src
	368	opcode = self.scanner.token
	369	self.scanner.scan()
	370	dest = self.locexpr()
	371	self.scanner.expect(',')
	372	src = self.indlocexpr()
	373	return Instr(opcode=opcode, dest=dest, src=src, index=None)
	374	elif self.scanner.token in ("add", "sub", "cmp", "and", "or", "xor"):
319	375	opcode = self.scanner.token
320	376	self.scanner.scan()
321	377	dest = self.locexpr()

330	386	self.scanner.scan()
331	387	src = self.locexpr()
332	388	self.scanner.expect(',')
333		dest = self.locexpr()
334		index = None
335		if self.scanner.consume('+'):
336		index = self.locexpr()
337		return Instr(opcode=opcode, dest=dest, src=src, index=index)
	389	dest = self.indlocexpr()
	390	return Instr(opcode=opcode, dest=dest, src=src, index=None)
338	391	elif self.scanner.token in ("shl", "shr", "inc", "dec"):
339	392	opcode = self.scanner.token
340	393	self.scanner.scan()

351	404	elif self.scanner.token in ("copy",):
352	405	opcode = self.scanner.token
353	406	self.scanner.scan()
354		src = self.indlocexpr()
	407	src = self.indlocexpr(forward=True)
355	408	self.scanner.expect(',')
356	409	dest = self.indlocexpr()
357	410	instr = Instr(opcode=opcode, dest=dest, src=src)

+224

-4

tests/SixtyPical Analysis.md less more

87	87	\| ld x, 0
88	88	\| }
89	89	= ok
	90
	91	This is true regardless of whether it's an input or not.
	92
	93	\| routine main
	94	\| inputs x
	95	\| {
	96	\| ld x, 0
	97	\| }
	98	? ForbiddenWriteError: x in main
	99
	100	\| routine main
	101	\| inputs x
	102	\| outputs x, z, n
	103	\| {
	104	\| ld x, 0
	105	\| }
	106	= ok
	107
	108	\| routine main
	109	\| inputs x
	110	\| trashes x, z, n
	111	\| {
	112	\| ld x, 0
	113	\| }
	114	= ok
	115
	116	If a routine trashes a location, this must be declared.
	117
	118	\| routine foo
	119	\| trashes x
	120	\| {
	121	\| trash x
	122	\| }
	123	= ok
	124
	125	\| routine foo
	126	\| {
	127	\| trash x
	128	\| }
	129	? ForbiddenWriteError: x in foo
	130
	131	\| routine foo
	132	\| outputs x
	133	\| {
	134	\| trash x
	135	\| }
	136	? UnmeaningfulOutputError: x in foo
	137
	138	If a routine causes a location to be trashed, this must be declared in the caller.
	139
	140	\| routine trash_x
	141	\| trashes x, z, n
	142	\| {
	143	\| ld x, 0
	144	\| }
	145	\|
	146	\| routine foo
	147	\| trashes x, z, n
	148	\| {
	149	\| call trash_x
	150	\| }
	151	= ok
	152
	153	\| routine trash_x
	154	\| trashes x, z, n
	155	\| {
	156	\| ld x, 0
	157	\| }
	158	\|
	159	\| routine foo
	160	\| trashes z, n
	161	\| {
	162	\| call trash_x
	163	\| }
	164	? ForbiddenWriteError: x in foo
	165
	166	\| routine trash_x
	167	\| trashes x, z, n
	168	\| {
	169	\| ld x, 0
	170	\| }
	171	\|
	172	\| routine foo
	173	\| outputs x
	174	\| trashes z, n
	175	\| {
	176	\| call trash_x
	177	\| }
	178	? UnmeaningfulOutputError: x in foo
90	179
91	180	If a routine reads or writes a user-define memory location, it needs to declare that too.
92	181

1232	1321	be initialized in the other.
1233	1322
1234	1323	\| routine foo
1235		\| inputs x
1236	1324	\| outputs x
1237	1325	\| trashes a, z, n, c
1238	1326	\| {
	1327	\| ld x, 0
1239	1328	\| ld a, 0
1240	1329	\| cmp a, 42
1241	1330	\| if z {

1246	1335	\| }
1247	1336	= ok
1248	1337
	1338	\| routine foo
	1339	\| inputs x
	1340	\| outputs x
	1341	\| trashes a, z, n, c
	1342	\| {
	1343	\| ld a, 0
	1344	\| cmp a, 42
	1345	\| if z {
	1346	\| ld x, 7
	1347	\| } else {
	1348	\| ld a, 23
	1349	\| }
	1350	\| }
	1351	= ok
	1352
1249	1353	An `if` with a single block is analyzed as if it had an empty `else` block.
1250	1354
1251	1355	\| routine foo

1285	1389	\| }
1286	1390	\| }
1287	1391	= ok
	1392
	1393	The cardinal rule for trashes in an `if` is the "union rule": if one branch
	1394	trashes {`a`} and the other branch trashes {`b`} then the whole `if` statement
	1395	trashes {`a`, `b`}.
	1396
	1397	\| routine foo
	1398	\| inputs a, x, z
	1399	\| trashes a, x
	1400	\| {
	1401	\| if z {
	1402	\| trash a
	1403	\| } else {
	1404	\| trash x
	1405	\| }
	1406	\| }
	1407	= ok
	1408
	1409	\| routine foo
	1410	\| inputs a, x, z
	1411	\| trashes a
	1412	\| {
	1413	\| if z {
	1414	\| trash a
	1415	\| } else {
	1416	\| trash x
	1417	\| }
	1418	\| }
	1419	? ForbiddenWriteError: x in foo
	1420
	1421	\| routine foo
	1422	\| inputs a, x, z
	1423	\| trashes x
	1424	\| {
	1425	\| if z {
	1426	\| trash a
	1427	\| } else {
	1428	\| trash x
	1429	\| }
	1430	\| }
	1431	? ForbiddenWriteError: a in foo
1288	1432
1289	1433	### repeat ###
1290	1434

1461	1605	\| }
1462	1606	= ok
1463	1607
	1608	The understanding is that, because `copy` trashes `a`, `a` cannot be used
	1609	as the destination of a `copy`.
	1610
	1611	\| byte source : 0
	1612	\| byte dest
	1613	\|
	1614	\| routine main
	1615	\| inputs source
	1616	\| outputs dest
	1617	\| trashes a, z, n
	1618	\| {
	1619	\| copy source, a
	1620	\| }
	1621	? ForbiddenWriteError
	1622
1464	1623	Can `copy` from a `word` to a `word`.
1465	1624
1466	1625	\| word source : 0

1503	1662	\| }
1504	1663	? TypeMismatchError
1505	1664
1506		### copy[] ###
1507
1508		Buffers and pointers.
	1665	### Buffers and pointers ###
1509	1666
1510	1667	Note that `^buf` is a constant value, so it by itself does not require `buf` to be
1511	1668	listed in any input/output sets.

1584	1741	\| ld y, 0
1585	1742	\| copy ^buf, ptr
1586	1743	\| copy [ptr] + y, foo
	1744	\| }
	1745	= ok
	1746
	1747	Read through a pointer to the `a` register. Note that this is done with `ld`,
	1748	not `copy`.
	1749
	1750	\| buffer[2048] buf
	1751	\| pointer ptr
	1752	\| byte foo
	1753	\|
	1754	\| routine main
	1755	\| inputs buf
	1756	\| outputs a
	1757	\| trashes y, z, n, ptr
	1758	\| {
	1759	\| ld y, 0
	1760	\| copy ^buf, ptr
	1761	\| ld a, [ptr] + y
	1762	\| }
	1763	= ok
	1764
	1765	Write the `a` register through a pointer. Note that this is done with `st`,
	1766	not `copy`.
	1767
	1768	\| buffer[2048] buf
	1769	\| pointer ptr
	1770	\| byte foo
	1771	\|
	1772	\| routine main
	1773	\| inputs buf
	1774	\| outputs buf
	1775	\| trashes a, y, z, n, ptr
	1776	\| {
	1777	\| ld y, 0
	1778	\| copy ^buf, ptr
	1779	\| ld a, 255
	1780	\| st a, [ptr] + y
1587	1781	\| }
1588	1782	= ok
1589	1783

2088	2282	\| copy foo, vec
2089	2283	\| }
2090	2284	= ok
	2285
	2286	### static ###
	2287
	2288	When memory locations are defined static to a routine, they cannot be
	2289	directly input, nor directly output; and since they are always initialized,
	2290	they cannot be trashed. Thus, they really don't participate in the analysis.
	2291
	2292	\| define foo routine
	2293	\| inputs x
	2294	\| outputs x
	2295	\| trashes z, n
	2296	\| static byte t : 0
	2297	\| {
	2298	\| st x, t
	2299	\| inc t
	2300	\| ld x, t
	2301	\| }
	2302	\|
	2303	\| define main routine
	2304	\| trashes a, x, z, n
	2305	\| static byte t : 0
	2306	\| {
	2307	\| ld x, t
	2308	\| call foo
	2309	\| }
	2310	= ok

+91

-3

tests/SixtyPical Compilation.md less more

528	528	= $081A INX
529	529	= $081B RTS
530	530
	531	Copy routine (by forward reference) to vector.
	532
	533	\| vector routine
	534	\| inputs x
	535	\| outputs x
	536	\| trashes z, n
	537	\| bar
	538	\|
	539	\| routine main
	540	\| outputs bar
	541	\| trashes a, n, z
	542	\| {
	543	\| copy foo, bar
	544	\| }
	545	\|
	546	\| routine foo
	547	\| inputs x
	548	\| outputs x
	549	\| trashes z, n
	550	\| {
	551	\| inc x
	552	\| }
	553	= $080D LDA #$18
	554	= $080F STA $081A
	555	= $0812 LDA #$08
	556	= $0814 STA $081B
	557	= $0817 RTS
	558	= $0818 INX
	559	= $0819 RTS
	560
531	561	Copy word to word table and back, with both `x` and `y` as indexes.
532	562
533	563	\| word one

633	663	\| outputs x
634	664	\| trashes a, z, n
635	665	\| one
636		\| vector (routine
	666	\| vector routine
637	667	\| outputs x
638		\| trashes a, z, n)
	668	\| trashes a, z, n
639	669	\| table[256] many
640	670	\|
641	671	\| routine bar outputs x trashes a, z, n {

845	875	\| ld y, 0
846	876	\| copy ^buf, ptr
847	877	\| copy [ptr] + y, foo
848		\| copy [ptr] + y, a
	878	\| ld a, [ptr] + y
849	879	\| }
850	880	= $080D LDY #$00
851	881	= $080F LDA #$1F

856	886	= $0819 STA $101F
857	887	= $081C LDA ($FE),Y
858	888	= $081E RTS
	889
	890	Write the `a` register through a pointer.
	891
	892	\| buffer[2048] buf
	893	\| pointer ptr @ 254
	894	\| byte foo
	895	\|
	896	\| routine main
	897	\| inputs buf
	898	\| outputs buf
	899	\| trashes a, y, z, n, ptr
	900	\| {
	901	\| ld y, 0
	902	\| copy ^buf, ptr
	903	\| ld a, 255
	904	\| st a, [ptr] + y
	905	\| }
	906	= $080D LDY #$00
	907	= $080F LDA #$1C
	908	= $0811 STA $FE
	909	= $0813 LDA #$08
	910	= $0815 STA $FF
	911	= $0817 LDA #$FF
	912	= $0819 STA ($FE),Y
	913	= $081B RTS
859	914
860	915	Add a word memory location, and a literal word, to a pointer, and then read through it.
861	916	Note that this is not range-checked. (Yet.)

920	975	= $080D TAX
921	976	= $080E LDA #$00
922	977	= $0810 RTS
	978
	979	### static ###
	980
	981	Memory locations defined static to a routine are allocated
	982	just the same as initialized global storage locations are.
	983
	984	\| define foo routine
	985	\| inputs x
	986	\| outputs x
	987	\| trashes z, n
	988	\| static byte t : 255
	989	\| {
	990	\| st x, t
	991	\| inc t
	992	\| ld x, t
	993	\| }
	994	\|
	995	\| define main routine
	996	\| trashes a, x, z, n
	997	\| static byte t : 7
	998	\| {
	999	\| ld x, t
	1000	\| call foo
	1001	\| }
	1002	= $080D LDX $081F
	1003	= $0810 JSR $0814
	1004	= $0813 RTS
	1005	= $0814 STX $081E
	1006	= $0817 INC $081E
	1007	= $081A LDX $081E
	1008	= $081D RTS
	1009	= $081E .byte $FF
	1010	= $081F .byte $07

+68

-18

tests/SixtyPical Syntax.md less more

407	407	\| }
408	408	= ok
409	409
410		A routine can be copied into a vector before the routine appears in the program,
411		however, it must be marked as such with the keyword `forward`.
	410	A routine can be copied into a vector before the routine appears in the program.
	411	This is known as a "forward reference". You are only allowed to make forward
	412	references in the source of a `copy` instruction.
412	413
413	414	\| vector routine
414	415	\| inputs cinv, a

424	425	\| routine foo {
425	426	\| ld a, 0
426	427	\| }
427		? SyntaxError: Undefined symbol
428
429		\| vector routine
430		\| inputs cinv, a
431		\| outputs cinv, x
432		\| trashes a, x, z, n
433		\| cinv @ 788
434		\| routine main {
435		\| with interrupts off {
436		\| copy forward foo, cinv
437		\| }
438		\| call cinv
439		\| }
440		\| routine foo {
441		\| ld a, 0
442		\| }
443	428	= ok
444	429
445	430	goto.

528	513	\| ld a, 0
529	514	\| }
530	515	? SyntaxError
	516
	517	Memory locations can be defined static to a routine.
	518
	519	\| define foo routine
	520	\| inputs x
	521	\| outputs x
	522	\| trashes z, n
	523	\| static byte t : 0
	524	\| {
	525	\| st x, t
	526	\| inc t
	527	\| ld x, t
	528	\| }
	529	\|
	530	\| define main routine
	531	\| trashes a, x, z, n
	532	\| static byte t : 0
	533	\| {
	534	\| ld x, t
	535	\| call foo
	536	\| }
	537	= ok
	538
	539	Static memory locations must always be given an initial value.
	540
	541	\| define main routine
	542	\| inputs x
	543	\| outputs x
	544	\| trashes z, n
	545	\| static byte t
	546	\| {
	547	\| st x, t
	548	\| inc t
	549	\| ld x, t
	550	\| }
	551	? SyntaxError
	552
	553	Name of a static cannot shadow an existing global or static.
	554
	555	\| byte t
	556	\|
	557	\| define main routine
	558	\| inputs x
	559	\| outputs x
	560	\| trashes z, n
	561	\| static byte t
	562	\| {
	563	\| st x, t
	564	\| inc t
	565	\| ld x, t
	566	\| }
	567	? SyntaxError
	568
	569	\| define main routine
	570	\| inputs x
	571	\| outputs x
	572	\| trashes z, n
	573	\| static byte t
	574	\| static byte t
	575	\| {
	576	\| st x, t
	577	\| inc t
	578	\| ld x, t
	579	\| }
	580	? SyntaxError