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31 * Declaration of the Packet class.
34 #ifndef __MEM_PACKET_HH__
35 #define __MEM_PACKET_HH__
37 #include "mem/request.hh"
38 #include "arch/isa_traits.hh"
39 #include "sim/root.hh"
42 typedef Packet* PacketPtr;
43 typedef uint8_t* PacketDataPtr;
46 * A Packet is used to encapsulate a transfer between two objects in
47 * the memory system (e.g., the L1 and L2 cache). (In contrast, a
48 * single Request travels all the way from the requester to the
49 * ultimate destination and back, possibly being conveyed by several
50 * different Packets along the way.)
55 /** A pointer to the data being transfered. It can be differnt
56 * sizes at each level of the heirarchy so it belongs in the
57 * packet, not request. This may or may not be populated when a
58 * responder recieves the packet. If not populated it memory
59 * should be allocated.
63 /** Is the data pointer set to a value that shouldn't be freed
64 * when the packet is destroyed? */
66 /** The data pointer points to a value that should be freed when
67 * the packet is destroyed. */
69 /** the data pointer points to an array (thus delete [] ) needs to
70 * be called on it rather than simply delete.*/
74 /** The address of the request. This address could be virtual or
75 * physical, depending on the system configuration. */
78 /** The size of the request or transfer. */
81 /** Device address (e.g., bus ID) of the source of the
82 * transaction. The source is not responsible for setting this
83 * field; it is set implicitly by the interconnect when the
84 * packet * is first sent. */
87 /** Device address (e.g., bus ID) of the destination of the
88 * transaction. The special value Broadcast indicates that the
89 * packet should be routed based on its address. This field is
90 * initialized in the constructor and is thus always valid
91 * (unlike * addr, size, and src). */
94 /** Are the 'addr' and 'size' fields valid? */
96 /** Is the 'src' field valid? */
101 /** The special destination address indicating that the packet
102 * should be routed based on its address. */
103 static const short Broadcast = -1;
105 /** A pointer to the original request. */
108 /** A virtual base opaque structure used to hold coherence-related
109 * state. A specific subclass would be derived from this to
110 * carry state specific to a particular coherence protocol. */
111 class CoherenceState {
113 virtual ~CoherenceState() {}
116 /** This packet's coherence state. Caches should use
117 * dynamic_cast<> to cast to the state appropriate for the
118 * system's coherence protocol. */
119 CoherenceState *coherence;
121 /** A virtual base opaque structure used to hold state associated
122 * with the packet but specific to the sending device (e.g., an
123 * MSHR). A pointer to this state is returned in the packet's
124 * response so that the sender can quickly look up the state
125 * needed to process it. A specific subclass would be derived
126 * from this to carry state specific to a particular sending
130 virtual ~SenderState() {}
133 /** This packet's sender state. Devices should use dynamic_cast<>
134 * to cast to the state appropriate to the sender. */
135 SenderState *senderState;
138 /** List of command attributes. */
139 enum CommandAttribute
144 IsInvalidate = 1 << 3,
147 NeedsResponse = 1 << 6,
151 /** List of all commands associated with a packet. */
154 ReadReq = IsRead | IsRequest | NeedsResponse,
155 WriteReq = IsWrite | IsRequest | NeedsResponse,
156 WriteReqNoAck = IsWrite | IsRequest,
157 ReadResp = IsRead | IsResponse,
158 WriteResp = IsWrite | IsResponse
161 /** Return the string name of the cmd field (for debugging and
163 const std::string &cmdString() const;
165 /** The command field of the packet. */
168 bool isRead() { return (cmd & IsRead) != 0; }
169 bool isRequest() { return (cmd & IsRequest) != 0; }
170 bool isResponse() { return (cmd & IsResponse) != 0; }
171 bool needsResponse() { return (cmd & NeedsResponse) != 0; }
173 /** Possible results of a packet's request. */
181 /** The result of this packet's request. */
184 /** Accessor function that returns the source index of the packet. */
185 short getSrc() const { assert(srcValid); return src; }
186 void setSrc(short _src) { src = _src; srcValid = true; }
188 /** Accessor function that returns the destination index of
190 short getDest() const { return dest; }
191 void setDest(short _dest) { dest = _dest; }
193 Addr getAddr() const { assert(addrSizeValid); return addr; }
194 int getSize() const { assert(addrSizeValid); return size; }
196 /** Constructor. Note that a Request object must be constructed
197 * first, but the Requests's physical address and size fields
198 * need not be valid. The command and destination addresses
199 * must be supplied. */
200 Packet(Request *_req, Command _cmd, short _dest)
201 : data(NULL), staticData(false), dynamicData(false), arrayData(false),
202 addr(_req->paddr), size(_req->size), dest(_dest),
203 addrSizeValid(_req->validPaddr),
205 req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
214 /** Reinitialize packet address and size from the associated
215 * Request object, and reset other fields that may have been
216 * modified by a previous transaction. Typically called when a
217 * statically allocated Request/Packet pair is reused for
218 * multiple transactions. */
219 void reinitFromRequest() {
220 assert(req->validPaddr);
223 addrSizeValid = true;
232 /** Take a request packet and modify it in place to be suitable
233 * for returning as a response to that request. Used for timing
234 * accesses only. For atomic and functional accesses, the
235 * request packet is always implicitly passed back *without*
236 * modifying the command or destination fields, so this function
237 * should not be called. */
238 void makeTimingResponse() {
239 assert(needsResponse());
241 icmd &= ~(IsRequest | NeedsResponse);
248 /** Set the data pointer to the following value that should not be freed. */
249 template <typename T>
250 void dataStatic(T *p);
252 /** Set the data pointer to a value that should have delete [] called on it.
254 template <typename T>
255 void dataDynamicArray(T *p);
257 /** set the data pointer to a value that should have delete called on it. */
258 template <typename T>
259 void dataDynamic(T *p);
261 /** return the value of what is pointed to in the packet. */
262 template <typename T>
265 /** get a pointer to the data ptr. */
266 template <typename T>
269 /** set the value in the data pointer to v. */
270 template <typename T>
273 /** delete the data pointed to in the data pointer. Ok to call to matter how
274 * data was allocted. */
277 /** If there isn't data in the packet, allocate some. */
280 /** Do the packet modify the same addresses. */
281 bool intersect(Packet *p);
284 bool fixPacket(Packet *func, Packet *timing);
285 #endif //__MEM_PACKET_HH