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
|
-- Copyright (C) 1996 Morgan Kaufmann Publishers, Inc
-- This file is part of VESTs (Vhdl tESTs).
-- VESTs is free software; you can redistribute it and/or modify it
-- under the terms of the GNU General Public License as published by the
-- Free Software Foundation; either version 2 of the License, or (at
-- your option) any later version.
-- VESTs is distributed in the hope that it will be useful, but WITHOUT
-- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-- FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
-- for more details.
-- You should have received a copy of the GNU General Public License
-- along with VESTs; if not, write to the Free Software Foundation,
-- Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-- ---------------------------------------------------------------------
--
-- $Id: ch_07_fg_07_22.vhd,v 1.2 2001-10-26 16:29:34 paw Exp $
-- $Revision: 1.2 $
--
-- ---------------------------------------------------------------------
-- not in book
entity cache is
end entity cache;
-- end not in book
architecture behavioral of cache is
-- not in book
subtype word is bit_vector(0 to 31);
signal mem_addr : natural;
signal mem_data_in : word;
signal mem_read, mem_ack : bit := '0';
-- end not in book
begin
behavior : process is
-- not in book
constant block_size : positive := 4;
type cache_block is array (0 to block_size - 1) of word;
type store_array is array (0 to 15) of cache_block;
variable data_store : store_array;
variable entry_index : natural := 1;
variable miss_base_address : natural := 16;
-- end not in book
-- . . .
procedure read_block( start_address : natural;
entry : out cache_block ) is
variable memory_address_reg : natural;
variable memory_data_reg : word;
procedure read_memory_word is
begin
mem_addr <= memory_address_reg;
mem_read <= '1';
wait until mem_ack = '1';
memory_data_reg := mem_data_in;
mem_read <= '0';
wait until mem_ack = '0';
end procedure read_memory_word;
begin -- read_block
for offset in 0 to block_size - 1 loop
memory_address_reg := start_address + offset;
read_memory_word;
entry(offset) := memory_data_reg;
end loop;
end procedure read_block;
begin -- behavior
-- . . .
read_block( miss_base_address, data_store(entry_index) );
-- . . .
-- not in book
wait;
-- end not in book
end process behavior;
-- not in book
memory : process is
type store_array is array (0 to 31) of word;
constant store : store_array :=
( X"00000000", X"00000001", X"00000002", X"00000003",
X"00000004", X"00000005", X"00000006", X"00000007",
X"00000008", X"00000009", X"0000000a", X"0000000b",
X"0000000c", X"0000000d", X"0000000e", X"0000000f",
X"00000010", X"00000011", X"00000012", X"00000013",
X"00000014", X"00000015", X"00000016", X"00000017",
X"00000018", X"00000019", X"0000001a", X"0000001b",
X"0000001c", X"0000001d", X"0000001e", X"0000001f" );
begin
wait until mem_read = '1';
mem_data_in <= store(mem_addr);
mem_ack <= '1';
wait until mem_read = '0';
mem_ack <= '0';
end process memory;
-- end not in book
end architecture behavioral;
|
