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r18536 Monday 15th October, 2012 at 14:06:24 UTC by Curt Coder
Optimized the PLA implementation and added simple caching with significant performance increase. [Curt Coder]

[src/emu/machine]

pla.c pla.h

trunk/src/emu/machine/pla.c

r18535	r18536
12	12
13	13
14	14	//**************************************************************************
15		//  DEVICE TYPE DEFINITION
	15	//  DEVICE TYPE DEFINITIONS
16	16	//**************************************************************************
17	17
18	18	const device_type PLS100 = &device_creator<pls100_device>;
r18535	r18536
21	21
22	22
23	23	//**************************************************************************
24		//  INLINE HELPERS
	24	//  LIVE DEVICE
25	25	//**************************************************************************
26	26
27	27	//-------------------------------------------------
	28	//  pla_device - constructor
	29	//-------------------------------------------------
	30
	31	pla_device::pla_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock, int inputs, int outputs, int terms, UINT32 input_mask)
	32	: device_t(mconfig, type, name, tag, owner, clock),
	33	m_inputs(inputs),
	34	m_outputs(outputs),
	35	m_terms(terms),
	36	m_input_mask(((UINT64)input_mask << 32) | input_mask)
	37	{
	38	}
	39
	40	pls100_device::pls100_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
	41	: pla_device(mconfig, PLS100, "PLS100", tag, owner, clock, 16, 8, 48, 0xffff)
	42	{
	43	}
	44
	45	mos8721_device::mos8721_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
	46	: pla_device(mconfig, MOS8721, "MOS8721", tag, owner, clock, 27, 18, 379, 0x7ffffff) // TODO actual number of terms is unknown
	47	{
	48	}
	49
	50
	51	//-------------------------------------------------
	52	//  device_start - device-specific startup
	53	//-------------------------------------------------
	54
	55	void pla_device::device_start()
	56	{
	57	assert(machine().root_device().memregion(tag()) != NULL);
	58
	59	// parse fusemap
	60	parse_fusemap();
	61
	62	// clear cache
	63	for (int i = 0; i < CACHE_SIZE; i++)
	64	{
	65	m_cache[i] = 0;
	66	}
	67
	68	m_cache_ptr = 0;
	69	}
	70
	71
	72	//-------------------------------------------------
28	73	//  parse_fusemap -
29	74	//-------------------------------------------------
30	75
31		inline void pla_device::parse_fusemap()
	76	void pla_device::parse_fusemap()
32	77	{
33	78	memory_region *region = machine().root_device().memregion(tag());
34	79	jed_data jed;
35	80
36	81	jedbin_parse(region->base(), region->bytes(), &jed);
37	82
38		//logerror("PLA '%s' %u fuses\n", tag(), jed.numfuses);
39
40	83	UINT32 fusenum = 0;
41		m_xor = 0;
42	84
43		for (int term = 0; term < m_terms; term++)
	85	for (int p = 0; p < m_terms; p++)
44	86	{
45		m_and_comp[term] = 0;
46		m_and_true[term] = 0;
47		m_or[term] = 0;
	87	term *term = &m_term[p];
48	88
	89	// AND mask
	90	term->m_and = 0;
	91
49	92	for (int i = 0; i < m_inputs; i++)
50	93	{
51		m_and_comp[term] |= jed_get_fuse(&jed, fusenum++) << i;
52		m_and_true[term] |= jed_get_fuse(&jed, fusenum++) << i;
	94	// complement
	95	term->m_and |= (UINT64)jed_get_fuse(&jed, fusenum++) << (i + 32);
	96
	97	// true
	98	term->m_and |= (UINT64)jed_get_fuse(&jed, fusenum++) << i;
53	99	}
54	100
	101	// OR mask
	102	term->m_or = 0;
	103
55	104	for (int f = 0; f < m_outputs; f++)
56	105	{
57		m_or[term] |= !jed_get_fuse(&jed, fusenum++) << f;
	106	term->m_or |= !jed_get_fuse(&jed, fusenum++) << f;
58	107	}
59	108
60		//logerror("PLA '%s' %3u COMP %08x TRUE %08x OR %08x\n", tag(), term, m_and_comp[term], m_and_true[term], m_or[term]);
	109	term->m_or <<= 32;
61	110	}
62	111
	112	// XOR mask
	113	m_xor = 0;
	114
63	115	for (int f = 0; f < m_outputs; f++)
64	116	{
65	117	m_xor |= jed_get_fuse(&jed, fusenum++) << f;
66	118	}
67	119
68		//logerror("PLA '%s' XOR %08x\n", tag(), m_xor);
	120	m_xor <<= 32;
69	121	}
70	122
71	123
72	124	//-------------------------------------------------
73		//  get_product -
	125	//  read -
74	126	//-------------------------------------------------
75	127
76		inline bool pla_device::get_product(int term)
	128	UINT32 pla_device::read(UINT32 input)
77	129	{
78		UINT32 input_comp = m_and_comp[term] | ~m_i;
79		UINT32 input_true = m_and_true[term] | m_i;
	130	// try the cache first
	131	for (int i = 0; i < CACHE_SIZE; ++i)
	132	{
	133	UINT64 cache_entry = m_cache[i];
80	134
81		//logerror("PLA '%s' %3u COMP %08x TRUE %08x OR %08x : %u\n", tag(), term, ~input_comp & m_output_mask, ~input_true & m_output_mask, m_or[term], (((input_comp & input_true) & m_output_mask) == m_output_mask));
	135	if ((UINT32)cache_entry == input)
	136	{
	137	// cache hit
	138	return cache_entry >> 32;
	139	}
	140	}
82	141
83		return ((input_comp & input_true) & m_output_mask) == m_output_mask;
84		}
	142	// cache miss, process terms
	143	UINT64 inputs = ((~(UINT64)input << 32) | input) & m_input_mask;
	144	UINT64 s = 0;
85	145
	146	for (int i = 0; i < m_terms; ++i)
	147	{
	148	term term = m_term[i];
86	149
87		//-------------------------------------------------
88		//  update_outputs -
89		//-------------------------------------------------
90
91		inline void pla_device::update_outputs()
92		{
93		m_s = 0;
94
95		for (int term = 0; term < m_terms; term++)
96		{
97		if (get_product(term))
	150	if ((term.m_and | inputs) == m_input_mask)
98	151	{
99		m_s |= m_or[term];
	152	s |= term.m_or;
100	153	}
101	154	}
102		}
103	155
	156	s ^= m_xor;
104	157
	158	// store output in cache
	159	m_cache[m_cache_ptr] = s | input;
	160	++m_cache_ptr &= (CACHE_SIZE - 1);
105	161
106		//**************************************************************************
107		//  LIVE DEVICE
108		//**************************************************************************
109
110		//-------------------------------------------------
111		//  pla_device - constructor
112		//-------------------------------------------------
113
114		pla_device::pla_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock, int inputs, int outputs, int terms, UINT32 output_mask)
115		: device_t(mconfig, type, name, tag, owner, clock),
116		m_inputs(inputs),
117		m_outputs(outputs),
118		m_terms(terms),
119		m_output_mask(output_mask)
120		{
	162	return s >> 32;
121	163	}
122
123		pls100_device::pls100_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
124		: pla_device(mconfig, PLS100, "PLS100", tag, owner, clock, 16, 8, 48, 0xffff)
125		{
126		}
127
128		mos8721_device::mos8721_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
129		: pla_device(mconfig, MOS8721, "MOS8721", tag, owner, clock, 27, 18, 379, 0x7ffffff) // TODO actual number of terms is unknown
130		{
131		}
132
133
134		//-------------------------------------------------
135		//  device_start - device-specific startup
136		//-------------------------------------------------
137
138		void pla_device::device_start()
139		{
140		// parse fusemap
141		assert(machine().root_device().memregion(tag()) != NULL);
142		parse_fusemap();
143
144		// register for state saving
145		save_item(NAME(m_i));
146		save_item(NAME(m_s));
147		}
148
149
150		//-------------------------------------------------
151		//  read -
152		//-------------------------------------------------
153
154		UINT32 pla_device::read(UINT32 input)
155		{
156		m_i = input;
157
158		update_outputs();
159
160		return m_s ^ m_xor;
161		}

trunk/src/emu/machine/pla.h

r18535	r18536
39	39	//**************************************************************************
40	40
41	41	#define MAX_TERMS       512
	42	#define CACHE_SIZE      8
42	43
43	44
44	45
r18535	r18536
71	72	// device-level overrides
72	73	virtual void device_start();
73	74
74		inline void parse_fusemap();
75		inline bool get_product(int term);
76		inline void update_outputs();
	75	void parse_fusemap();
77	76
78	77	int m_inputs;
79	78	int m_outputs;
80	79	int m_terms;
81		UINT32 m_output_mask;
	80	UINT64 m_input_mask;
	81	UINT64 m_xor;
82	82
83		UINT32 m_i;
84		UINT32 m_s;
85		UINT32 m_and_true[MAX_TERMS];
86		UINT32 m_and_comp[MAX_TERMS];
87		UINT32 m_or[MAX_TERMS];
88		UINT32 m_xor;
	83	struct term
	84	{
	85	UINT64 m_and;
	86	UINT64 m_or;
	87	};
	88
	89	term m_term[MAX_TERMS];
	90
	91	UINT64 m_cache[CACHE_SIZE];
	92	UINT8 m_cache_ptr;
89	93	};
90	94
91	95

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