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
|
/*
* Copyright (c) 2003 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* @file
* Declaration of the Packet Class, a packet is a transaction occuring
* between a single level of the memory heirarchy (ie L1->L2).
*/
#ifndef __MEM_PACKET_HH__
#define __MEM_PACKET_HH__
/** List of all commands associated with a packet. */
enum Command
{
Read,
Write
};
/** The result of a particular pakets request. */
enum PacketResult
{
Success,
BadAddress
};
/**
* A Packet is the structure to handle requests between two levels
* of the memory system. The Request is a global object that trancends
* all of the memory heirarchy, but at each levels interface a packet
* is created to transfer data/requests. For example, a request would
* be used to initiate a request to go to memory/IOdevices, as the request
* passes through the memory system several packets will be created. One
* will be created to go between the L1 and L2 caches and another to go to
* the next level and so forth.
*
* Packets are assumed to be returned in the case of a single response. If
* the transaction has no response, then the consumer will delete the packet.
*/
struct Packet
{
/** The address of the request, could be virtual or physical (depending on
cache configurations). */
Addr addr;
/** Flag structure to hold flags for this particular packet */
uint64_t flags;
/** A pointer to the overall request. */
RequestPtr req;
/** A virtual base opaque structure used to hold
coherence status messages. */
Coherence *coherence; // virtual base opaque,
// assert(dynamic_cast<Foo>) etc.
/** A virtual base opaque structure used to hold the senders state. */
SenderState *senderState; // virtual base opaque,
// assert(dynamic_cast<Foo>) etc.
/** A pointer to the data being transfered. It can be differnt sizes
at each level of the heirarchy so it belongs in the packet,
not request*/
PacketDataPtr data;
/** Indicates the size of the request. */
int size;
/** A index of the source of the transaction. */
short src;
/** A index to the destination of the transaction. */
short dest;
/** The command of the transaction. */
Command cmd;
/** The result of the packet transaction. */
PacketResult result;
/** Accessor function that returns the source index of the packet. */
short getSrc() const { return src; }
/** Accessor function that returns the destination index of
the packet. */
short getDest() const { return dest; }
};
#endif //__MEM_PACKET_HH
|
