aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/mem.h
blob: 6ea18f26f1a8d294415188ddf2da5aef875ae11e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
/*
 *  yosys -- Yosys Open SYnthesis Suite
 *
 *  Copyright (C) 2020  Marcelina Kościelnicka <mwk@0x04.net>
 *
 *  Permission to use, copy, modify, and/or distribute this software for any
 *  purpose with or without fee is hereby granted, provided that the above
 *  copyright notice and this permission notice appear in all copies.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

#ifndef MEM_H
#define MEM_H

#include "kernel/yosys.h"
#include "kernel/ffinit.h"

YOSYS_NAMESPACE_BEGIN

struct MemRd : RTLIL::AttrObject {
	bool removed;
	Cell *cell;
	int wide_log2;
	bool clk_enable, clk_polarity, ce_over_srst;
	Const arst_value, srst_value, init_value;
	bool transparent;
	SigSpec clk, en, arst, srst, addr, data;

	MemRd() : removed(false), cell(nullptr) {}

	// Returns the address of given subword index accessed by this port.
	SigSpec sub_addr(int sub) {
		SigSpec res = addr;
		for (int i = 0; i < wide_log2; i++)
			res[i] = State(sub >> i & 1);
		return res;
	}
};

struct MemWr : RTLIL::AttrObject {
	bool removed;
	Cell *cell;
	int wide_log2;
	bool clk_enable, clk_polarity;
	std::vector<bool> priority_mask;
	SigSpec clk, en, addr, data;

	MemWr() : removed(false), cell(nullptr) {}

	// Returns the address of given subword index accessed by this port.
	SigSpec sub_addr(int sub) {
		SigSpec res = addr;
		for (int i = 0; i < wide_log2; i++)
			res[i] = State(sub >> i & 1);
		return res;
	}
};

struct MemInit : RTLIL::AttrObject {
	bool removed;
	Cell *cell;
	Const addr;
	Const data;
	MemInit() : removed(false), cell(nullptr) {}
};

struct Mem : RTLIL::AttrObject {
	Module *module;
	IdString memid;
	bool packed;
	RTLIL::Memory *mem;
	Cell *cell;
	int width, start_offset, size;
	std::vector<MemInit> inits;
	std::vector<MemRd> rd_ports;
	std::vector<MemWr> wr_ports;

	// Removes this memory from the module.  The data in helper structures
	// is unaffected except for the cell/mem fields.
	void remove();

	// Commits all changes in helper structures into the module — ports and
	// inits marked as removed are actually removed, new ports/inits create
	// new cells, modified port/inits are commited into their existing
	// cells.  Note that this reindexes the ports and inits array (actually
	// removing the ports/inits marked as removed).
	void emit();

	// Marks all inits as removed.
	void clear_inits();

	// Checks consistency of this memory and all its ports/inits, using
	// log_assert.
	void check();

	// Gathers all initialization data into a single big const covering
	// the whole memory.  For all non-initialized bits, Sx will be returned.
	Const get_init_data() const;

	// Constructs and returns the helper structures for all memories
	// in a module.
	static std::vector<Mem> get_all_memories(Module *module);

	// Constructs and returns the helper structures for all selected
	// memories in a module.
	static std::vector<Mem> get_selected_memories(Module *module);

	// Converts a synchronous read port into an asynchronous one by
	// extracting the data (or, in some rare cases, address) register
	// into a separate cell, together with any soft-transparency
	// logic necessary to preserve its semantics.  Returns the created
	// register cell, if any.  Note that in some rare cases this function
	// may succeed and perform a conversion without creating a new
	// register — a nullptr result doesn't imply nothing was done.
	Cell *extract_rdff(int idx, FfInitVals *initvals);

	// Splits all wide ports in this memory into equivalent narrow ones.
	// This function performs no modifications at all to the actual
	// netlist unless and until emit() is called.
	void narrow();

	// If write port idx2 currently has priority over write port idx1,
	// inserts extra logic on idx1's enable signal to disable writes
	// when idx2 is writing to the same address, then removes the priority
	// from the priority mask.
	void emulate_priority(int idx1, int idx2);

	// Prepares for merging write port idx2 into idx1 (where idx1 < idx2).
	// Specifically, takes care of priority masks: any priority relations
	// that idx2 had are replicated onto idx1, unless they conflict with
	// priorities already present on idx1, in which case emulate_priority
	// is called.
	void prepare_wr_merge(int idx1, int idx2);

	// Prepares the memory for widening a port to a given width.  This
	// involves ensuring that start_offset and size are aligned to the
	// target width.
	void widen_prep(int wide_log2);

	// Widens a write port up to a given width.  The newly port is
	// equivalent to the original, made by replicating enable/data bits
	// and masking enable bits with decoders on the low part of the
	// original address.
	void widen_wr_port(int idx, int wide_log2);

	Mem(Module *module, IdString memid, int width, int start_offset, int size) : module(module), memid(memid), packed(false), mem(nullptr), cell(nullptr), width(width), start_offset(start_offset), size(size) {}
};

YOSYS_NAMESPACE_END

#endif