1. (Adapted from Patterson and Hennessy). Referring to the diagram of a simulate

Question

1. (Adapted from Patterson and Hennessy). Referring to the diagram of a simulated MIPS CPU implementation that was handed out in class, consider what would happen if one of the control signals were "stuck" at some value - i.e., due to a hardware fault, the signal always had some particular value, regardless of what its value should be. For each of the following cases, indicate which group(s) of instructions in the MIPS ISA (ilf any) would still execute correctly (i.e. they either don't use the relevant portion of the datapaths at all, or they require this control signal to be the value that it's stuck at anyway.) Consider each of the following groups of instructions for each part below, and for each part list which groups will execute correctly and briefly indicate why you reached the conclusion you did. » R-Type (all R-format except jr) I-format immediate I-format load ·I-format store I-format branch al Example: Control word bit used to control what gets written into a register in the register set stuck at 0, rest OK: R-Type, I-format immediate, jal - OK; correct value for these I-format load - would fail: can't store result. jr, I-format store, I-format branch,j - OK: don't write to registers anyway Control word bit used to control what gets written into a register stuck at 1, rest OK Control word bit used to control the first of the two sources to the ALU stuck at 0, rest OK a. b. c. Control word bit used to control what serves as the memory address stuck at 0, rest OK d. Control word bit used to control what serves as the memory address stuck at 1, rest OK

Explanation / Answer

#include "contiki.h"
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#include "net/rime.h"
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#include <string.h>
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#include "dev/button-sensor.h"
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#include "dev/sensinode-sensors.h"
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#include "dev/leds.h"
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#include <stdio.h>
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#define TABLELENGTH ten //Route table length
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#define COMMAND_ROUTREQUEST 0x20 //Command for requesting route
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#define COMMAND_ROUTERESPONSE 0x21 //Command for route response
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#define COMMAND_DTATTX 0x22 //Command for causing knowledge through unicast
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#define BATTERY_AVERGE_LVL 3000 //Average battery level in mV for determinative if the
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//battery level is decent
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typedef struct //Structure that defines the content of the route table
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{
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uint16_t u16Dest; //The destination address
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uint16_t u16NextHop; //The next hop that points to the destination address
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uint16_t u16Battery; //The battery level of future hop
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uint16_t u16Rssi; //The rssi received from future hop
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} tsRouteTable;
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static tsRouteTable sRouteTable[TABLELENGTH]; //Declare a route table whose length is TABLELENGTH
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static rimeaddr_t addr; //Static variable holding address information for the utilization of unicast
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//static uint8_t destination;
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static struct unicast_conn uc; //Variable for unicast association
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static struct broadcast_conn bc; //Variable for broadcast association
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static uint8_t u8DataBuffer[50]; //Local knowledge buffer
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static const struct broadcast_callbacks broadcast_callbacks = ; //Broadcast recall registration
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static const struct unicast_callbacks unicast_callbacks = ; //Unicast recall registration
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static int rv; //Variable for briefly holding device reading
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static struct devices_sensor * sensor; //Variable containing sensor structure
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static float sane = 0; //Parameters for changing device readings
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static uint16_t battery; //Variable for holding battery reading
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static uint8_t temperature1=0; //Variable for holding temperature reading
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static uint8_t temperature2=0; //Variable for holding temperature reading
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static uint8_t brdcstCounter=1; //Counter for recording the quantity of broadcasting
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static uint8_t brdcstLimit=4; //Upper limit for limiting the quantity of broadcasting
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static uint8_t brdcstID=1; //Broadcast id for characteristic the published message
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/*---------------------------------------------------------------------------*/
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PROCESS(routenode_process, "Multihop Demo"); //Define a method whose name is "Multihop Demo"
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AUTOSTART_PROCESSES(&routenode_process); //Declare {the method|the method} as associate motorcar begin process, which is able to be mechanically
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//loaded once the system is power up
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/*---------------------------------------------------------------------------*/
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static void
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recv_uc(struct unicast_conn *c, const rimeaddr_t *from)
059
{
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uint8_t * data; //Pointer that points to the received buffer
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uint16_t dest=0; //Temporary variable for holding the address
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uint16_t nexthop=0; //Temporary variable for holding the address of future hop
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uint16_t src=0; //Temporary variable for holding the address of the node that sends back route response
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uint16_t battery=0; //Temporary variable for holding the battery level of the router
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uint16_t rssi=0; //Temporary variable for holding the rssi worth from the router
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static int i=0;
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static int m=0;
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unsigned int bSuccess=0; //Flag
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unsigned int bFound=0; //Flag
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073
knowledge = packetbuf_dataptr(); //Obtain the received buffer
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075
  
076
switch(data[0]) //The initial part of the received buffer specifies the command name
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ar requested to investigate the content of the received message
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The second and also the thrid components of the message area unit the upper eight bits
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and lower eight bits of the destination address, that is antecedently requested
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by the route request. Please offer this worth to the variable "dest". */
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dest = data[1];
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dest = dest << 8;
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dest = dest | data[2];
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/* Your area unit requested to abstract the address of the src node that sends this response to this node,
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and provides this worth to the variable "src" */
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src = from->u8[1];
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src = src <<8;
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src = src | from->u8[0];
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096

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/* The fourth and fifth components of the received buffer area unit the upper eight bits and
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lower eight bits of the battery level of the node that sends out this route response
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Please offer the battery level to the variable "battery" */
100
  
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battery=data[3];
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battery=battery<<8;
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battery=battery|data[4];
104
  
105
/* Please offer the worth of rssi to the variable "rssi" */
106
  
107
rssi=packetbuf_attr(PACKETBUF_ATTR_RSSI);
108

109

110
//Search the route table for change
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for(i=0; i<TABLELENGTH; i++)
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is found within the route table
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if(sRouteTable[i].u16Dest==dest)
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to point the destination is found
118
bSuccess=1;
119

120
//If this next hop for the destination node
121
//is a similar because the one that sends out this route
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//response, merely update this entry
123
if(sRouteTable[i].u16NextHop == src)
124
else{
128
//If this next hop is totally different from the
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//node that sends out this route response, and
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//if its battery level is bigger than
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// the typical level
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if(battery > BATTERY_AVERGE_LVL)
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create a comparison of the rssi worth between
138
this situated route entry and also the received
139
rssi. future hop with the stronger rssi ought to
140
be remained */
141

142

143

144

145
}else{
146

147
/* If the battery level of the node that sends
148
out this route response is a smaller amount than the typical level,
149
build a comparison with this battery level
150
recorded within the route entry */
151

152

153

154

155
}
156
break;
157
}
158
}
159
}
160

161
/* If no route entry is matched, which suggests the received route
162
response could be a recent one. Please found associate empty entry from
163
the route table, and store the received data. */
164
if(!bSuccess)
165
  
175
}
176
}
177
break;
178

179
default:
180
break;
181
}
182

183
packetbuf_clear();
184
}
185

186
static void
187
recv_bc(struct broadcast_conn *c, rimeaddr_t *from)
188

192

193

194
/*---------------------------------------------------------------------------*/
195
PROCESS_THREAD(routenode_process, ev, data)
196
mounted timer
198
static uint8_t i=0;   
199
static uint8_t m=0;
200
static int dec; //Parameter for device reading conversion
201
static float frac; //Parameter for device reading conversion
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static uint16_t u16Dest=0xffff;   
203
static uint8_t bFound=0; //Flag
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205
PROCESS_EXITHANDLER(unicast_close(&uc);)/> //Close the unicast association to avoid the collision that it's going to cause
206
PROCESS_BEGIN(); //Start this method
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208
for(i=0; i<TABLELENGTH; i++) //Initialize the route table
209
  
215

216

217
puts("start");
218

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/* Please open the published channel and unicast channel
220
on 128 and 129 severally */
221

222
broadcast_open(&bc, 128, &broadcast_callbacks);
223
unicast_open(&uc, 129, &unicast_callbacks);
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225

226

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/* Please begin the timer which is able to expire in a pair of seconds */
228
  
229

230

231

232
etimer_set(&et, CLOCK_SECOND * 2);
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234

235

236

237
while(1)
238
{
239

240
PROCESS_WAIT_EVENT_UNTIL(etimer_expired(&et));
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242
device = sensors_find(ADC_SENSOR);
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if(i==0) //If the flage i is even
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browse the temperature device, and provides its number half
247
to the variable "temperature1", and provides the decimal half to
248
the variable "temperture2" */
249
  
250
RV = sensor->value(ADC_SENSOR_TYPE_TEMP);
251
if(rv != -1) zero.61065 - 773) / a pair of.45);
253
temperature1=sane;
254
temperature2=sane-dec;
255

256

257

258
  
259
}
260

261
/* Please scan the VDD (voltage) device, convert the worth into the
262
form of mV, and provides the worth to the variable "battery" */
263
  
264

265

266
RV = sensor->value(ADC_SENSOR_TYPE_BATTERY);
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if(rv != -1) rather than hard-coding three.3 here, use the most recent VDD (stored in dec)
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* (slightly inaccurate still, however higher than crude three.3) */
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sane = (11.25 * RV * dec) / (0x7FE002);
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battery= 1000*sane;
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275

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//After the completion of reading sensors, the sender ought to broadcast
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//a route request.
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u8DataBuffer[0] = COMMAND_ROUTREQUEST;
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u8DataBuffer[1] = u16Dest>>8;
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u8DataBuffer[2] = u16Dest;
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u8DataBuffer[3] = brdcstCounter;
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u8DataBuffer[4] = brdcstLimit;
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u8DataBuffer[5] = brdcstID;
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brdcstID++;
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packetbuf_copyfrom(u8DataBuffer, 6);
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/* please fill in: decision broadcast */
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broadcast_send(&bc);
289
}
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}else
299
}
300

301
if(bFound){
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303
/* Please fill within the output knowledge buffer, u8DataBuffer
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1. the primary part of the buffer is that the command name, that is "COMMAND_DTATTX"
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2. The second and third elemets area unit the high eight bits and lower eight bites of the destination
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address, whose worth is capable the variable "u16Dest"*/
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u8DataBuffer[0]= COMMAND_DTATTX;
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u8DataBuffer[1]=u16Dest>>8;
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u8DataBuffer[2]=u16Dest;
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u8DataBuffer[3] = rimeaddr_node_addr.u8[0];
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u8DataBuffer[4] = rimeaddr_node_addr.u8[1];
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/* 3. The sixth and seventh components area unit the number half and decimal a part of the temperature
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device reading
316
4. The eighth and ninth components area unit the upper eight bits and lower eight bits of battery level*/
317
u8DataBuffer[5]= temperature1;
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u8DataBuffer[6]= temperature2;
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u8DataBuffer[7]=battery>>8;
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u8DataBuffer[8]=battery;
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322

323

324

325

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packetbuf_copyfrom(u8DataBuffer, 9);
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addr.u8[0] = sRouteTable[m].u16NextHop;
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addr.u8[1] = sRouteTable[m].u16NextHop>>8;
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/* please fill in: decision unicast */
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unicast_send(&uc, &addr);
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}
334
}
335
  
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if(i==0)
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else
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345
}
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347
PROCESS_END();
348
}

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