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7f1b6bd9 MG |
1 | #define _GNU_SOURCE |
2 | #include<assert.h> | |
3 | #include<sched.h> | |
4 | #include<signal.h> | |
5 | #include<stdio.h> | |
6 | #include<stdlib.h> | |
7 | #include<time.h> | |
8 | #include<unistd.h> | |
9 | #include<sys/wait.h> | |
10 | ||
11 | #include<pthread.h> | |
12 | ||
13 | /* magic value to indicate upstream is dead */ | |
14 | #define UART_DEAD 2 | |
15 | ||
16 | /* only relevant instructions */ | |
17 | #define INSTR_NOP 0 | |
18 | #define INSTR_ROUTE 4 | |
19 | ||
20 | /* Doing nothing, waiting for an instruction */ | |
21 | #define STATE_IDLE 0 | |
22 | #define STATE_READ_INSTRUCTION 10 | |
23 | #define STATE_READ_NEWS_ADDRESS 20 | |
24 | #define STATE_READ_NEWS_DATA 30 | |
25 | /* Propagating the last received instruction | |
26 | (or waiting for neighbour to be ready so I can propagate) */ | |
27 | #define STATE_PROPAGATE 1 | |
28 | #define STATE_PROPAGATE2 11 | |
29 | /* Executing some instruction */ | |
30 | #define STATE_EXECUTE 2 | |
31 | /* Sending NEWS to neighbour | |
32 | (or waiting for neighbour to be ready so I can send) */ | |
33 | #define STATE_NEWS 3 | |
34 | #define STATE_NEWS2 13 | |
35 | #define STATE_NEWS3 23 | |
36 | ||
37 | // UART encoding is: to send the byte [b] we write [b * 2 + 1] in the | |
38 | // given location, then on the next cycle we write 0. | |
39 | ||
40 | static void wait_cycles(int cycles) { | |
41 | struct timespec ts; | |
42 | long millis = 200; | |
43 | millis += (long)(rand() % 100 - 50); | |
44 | millis *= cycles; | |
45 | ts.tv_sec = millis / 1000; | |
46 | ts.tv_nsec = (millis % 1000) * 100000; | |
47 | nanosleep(&ts, NULL); | |
48 | } | |
49 | ||
50 | /* sleep for 150-250ms */ | |
51 | static void wait_one_cycle(void) { | |
52 | wait_cycles(1); | |
53 | } | |
54 | ||
55 | #define BLOG_THREAD_STARTED 0 | |
56 | #define BLOG_UART_BAD_KIND 1 | |
57 | #define BLOG_READ_INSTRUCTION 2 | |
58 | #define BLOG_READ_NEWS_ADDRESS 3 | |
59 | #define BLOG_READ_NEWS_DATA 4 | |
60 | #define BLOG_BECAME_NOT_READY 5 | |
61 | #define BLOG_INVALID_STATE 6 | |
62 | #define BLOG_EXECUTED_INSTR 7 | |
63 | #define BLOG_MANUFACTURED_INSTRUCTION 8 | |
64 | #define BLOG_READ_KIND 9 | |
65 | #define BLOG_TRY_SENDING_NEWS 10 | |
66 | #define BLOG_DONE_SENDING_NEWS 11 | |
67 | ||
68 | const char *blog_what[] = { | |
69 | "thread started", | |
70 | "uart bad kind", | |
71 | "read instruction", | |
72 | "read news address", | |
73 | "read news data", | |
74 | "ERROR: downstream became not ready!", | |
75 | "ERROR: invalid state", | |
76 | "executed instruction", | |
77 | "manufactured instruction", | |
78 | "read kind from uart", | |
79 | "trying to send news", | |
80 | "finished sending news", | |
81 | }; | |
82 | ||
83 | struct blog { | |
84 | int who; | |
85 | int what; | |
86 | int data; | |
87 | }; | |
88 | ||
89 | static volatile struct blog blog[1000]; | |
90 | static volatile int blog_n = 0; | |
91 | ||
92 | void display_post(int i) { | |
93 | printf("\033[3%dm%d: %s (%d)\033[0m\n", blog[i].who + 1, blog[i].who, blog_what[blog[i].what], blog[i].data); | |
94 | } | |
95 | ||
96 | void post(int who, int what, int data) { | |
97 | int idx = blog_n++; | |
98 | blog[idx].who = who; | |
99 | blog[idx].what = what; | |
100 | blog[idx].data = data; | |
101 | display_post(idx); | |
102 | } | |
103 | ||
104 | #define POST(what, data) post(id, what, data) | |
105 | ||
106 | int uart_data(int x) { | |
107 | return 2 * x + 1; | |
108 | } | |
109 | ||
110 | static void tx(volatile int *uart_tx, int data) { | |
111 | *uart_tx = data; | |
112 | wait_cycles(5); | |
113 | // assert(*uart_tx == 0); | |
114 | } | |
115 | ||
116 | #define TX(data) tx(uart_tx, uart_data(data)) | |
117 | #define KILL_UART() tx(uart_tx, 2) | |
118 | ||
119 | static int rx(volatile int *uart_rx) { | |
120 | int read = *uart_rx; | |
121 | *uart_rx = 0; | |
122 | return read; | |
123 | } | |
124 | ||
125 | #define RX() rx(uart_rx) | |
126 | ||
127 | void worker(int id, volatile int *uart_tx, volatile int *uart_rx, volatile int *ready_out, volatile const int *ready_in){ | |
128 | int current_instr = 0; | |
129 | ||
130 | int state = STATE_IDLE; | |
131 | *ready_out = 1; | |
132 | *uart_tx = 0; | |
133 | POST(BLOG_THREAD_STARTED, 0); | |
134 | ||
135 | int read, kind, instruction, address, data; | |
136 | ||
137 | while(1) { | |
138 | switch(state) { | |
139 | case STATE_IDLE: | |
140 | read = RX(); | |
141 | wait_one_cycle(); | |
142 | if(read == 2) { // upstream dead! | |
143 | KILL_UART(); | |
144 | return; | |
145 | } | |
146 | if(!read) /* nothing on uart */ | |
147 | break; | |
148 | kind = read >> 1; | |
149 | POST(BLOG_READ_KIND, kind); | |
150 | if(kind == 1) | |
151 | state = STATE_READ_INSTRUCTION; | |
152 | else if(kind == 2) | |
153 | state = STATE_READ_NEWS_ADDRESS; | |
154 | else | |
155 | POST(BLOG_UART_BAD_KIND, kind); | |
156 | break; | |
157 | ||
158 | case STATE_READ_INSTRUCTION: | |
159 | read = RX(); | |
160 | wait_one_cycle(); | |
161 | if(!read) /* nothing on uart */ | |
162 | break; | |
163 | instruction = read >> 1; | |
164 | current_instr = instruction; | |
165 | *ready_out = 0; | |
166 | POST(BLOG_READ_INSTRUCTION, instruction); | |
167 | state = STATE_PROPAGATE; | |
168 | break; | |
169 | ||
170 | case STATE_READ_NEWS_ADDRESS: | |
171 | read = RX(); | |
172 | wait_one_cycle(); | |
173 | if(!read) /* nothing on uart */ | |
174 | break; | |
175 | address = read >> 1; | |
176 | current_instr = address; | |
177 | POST(BLOG_READ_NEWS_ADDRESS, address); | |
178 | state = STATE_READ_NEWS_DATA; | |
179 | break; | |
180 | ||
181 | case STATE_READ_NEWS_DATA: | |
182 | read = RX(); | |
183 | wait_one_cycle(); | |
184 | if(!read) /* nothing on uart */ | |
185 | break; | |
186 | data = read >> 1; | |
187 | /* we now have the address in [current_instr] and data in [data]. | |
188 | We write a NOP instruction because we have no memory. */ | |
189 | current_instr = INSTR_NOP; | |
190 | *ready_out = 0; | |
191 | POST(BLOG_READ_NEWS_DATA, data); | |
192 | state = STATE_EXECUTE; | |
193 | break; | |
194 | ||
195 | case STATE_PROPAGATE: | |
196 | if(!*ready_in) | |
197 | break; | |
198 | TX(1); /* we're writing an instruction */ | |
199 | state = STATE_PROPAGATE2; | |
200 | break; | |
201 | ||
202 | case STATE_PROPAGATE2: | |
203 | if(!*ready_in) { | |
204 | POST(BLOG_BECAME_NOT_READY, state); | |
205 | state = STATE_PROPAGATE; | |
206 | break; | |
207 | } | |
208 | TX(current_instr); | |
209 | state = STATE_EXECUTE; | |
210 | break; | |
211 | ||
212 | case STATE_EXECUTE: | |
213 | wait_one_cycle(); // execution takes time! (not really) | |
214 | if(current_instr == INSTR_ROUTE) { | |
215 | state = STATE_NEWS; | |
216 | POST(BLOG_EXECUTED_INSTR, current_instr); | |
217 | // POST(BLOG_TRY_SENDING_NEWS, 0); | |
218 | } else { | |
219 | state = STATE_IDLE; | |
220 | *ready_out = 1; | |
221 | POST(BLOG_EXECUTED_INSTR, current_instr); | |
222 | } | |
223 | break; | |
224 | ||
225 | case STATE_NEWS: | |
226 | if(!*ready_in) | |
227 | break; | |
228 | TX(2); | |
229 | state = STATE_NEWS2; | |
230 | break; | |
231 | ||
232 | case STATE_NEWS2: | |
233 | if(!*ready_in) { | |
234 | POST(BLOG_BECAME_NOT_READY, state); | |
235 | state = STATE_NEWS; | |
236 | break; | |
237 | } | |
238 | TX(rand() & 0xFF); | |
239 | state = STATE_NEWS3; | |
240 | break; | |
241 | ||
242 | case STATE_NEWS3: | |
243 | if(!*ready_in) { | |
244 | POST(BLOG_BECAME_NOT_READY, state); | |
245 | state = STATE_NEWS; | |
246 | break; | |
247 | } | |
248 | TX(rand() & 0xFF); | |
249 | state = STATE_IDLE; | |
250 | *ready_out = 1; | |
251 | // POST(BLOG_DONE_SENDING_NEWS, 0); | |
252 | break; | |
253 | ||
254 | default: | |
255 | POST(BLOG_INVALID_STATE, state); | |
256 | break; | |
257 | } | |
258 | wait_one_cycle(); | |
259 | } | |
260 | } | |
261 | ||
262 | #define MASTER_SEND_INSTRUCTION 0 | |
263 | #define MASTER_SEND_INSTRUCTION2 10 | |
264 | #define MASTER_WAIT_FOR_NEWS 1 | |
265 | #define MASTER_READ_NEWS_ADDRESS 11 | |
266 | #define MASTER_READ_NEWS_DATA 21 | |
267 | #define MASTER_WAIT_FOR_PROPAGATE 2 | |
268 | #define MASTER_WAIT_FOR_PROPAGATE2 12 | |
269 | ||
270 | void master(volatile int *uart_tx, volatile int *uart_rx, volatile int *ready_out, volatile const int *ready_in){ | |
271 | int instructions_left = 10; | |
272 | int state = MASTER_SEND_INSTRUCTION; | |
273 | int ignore_next_rx = 0; | |
274 | const int id = 0; | |
275 | int read, kind, instruction, data, rnd; | |
276 | ||
277 | *uart_tx = 0; | |
278 | *ready_out = 1; | |
279 | POST(BLOG_THREAD_STARTED, 0); | |
280 | ||
281 | while(1) { | |
282 | switch(state) { | |
283 | case MASTER_SEND_INSTRUCTION: | |
284 | if(!instructions_left) { /* done! */ | |
285 | KILL_UART(); | |
286 | return; | |
287 | } | |
288 | if(!*ready_in) | |
289 | break; | |
290 | TX(1); | |
291 | state = MASTER_SEND_INSTRUCTION2; | |
292 | break; | |
293 | ||
294 | case MASTER_SEND_INSTRUCTION2: | |
295 | if(!*ready_in) { | |
296 | POST(BLOG_BECAME_NOT_READY, state); | |
297 | state = MASTER_SEND_INSTRUCTION; | |
298 | break; | |
299 | } | |
300 | /* manufacture an instruction */ | |
301 | rnd = rand() & 7; | |
302 | if(rnd <= 4) | |
303 | instruction = INSTR_NOP; | |
304 | else if(rnd <= 6) | |
305 | instruction = INSTR_ROUTE; | |
306 | else | |
307 | instruction = INSTR_ROUTE; /* actually READ */ | |
308 | ||
309 | POST(BLOG_MANUFACTURED_INSTRUCTION, rnd); | |
310 | TX(instruction); | |
311 | instructions_left--; | |
312 | ||
313 | if(instruction == INSTR_ROUTE) | |
314 | state = MASTER_WAIT_FOR_NEWS; | |
315 | else | |
316 | state = MASTER_WAIT_FOR_PROPAGATE; | |
317 | break; | |
318 | ||
319 | case MASTER_WAIT_FOR_PROPAGATE: | |
320 | read = RX(); | |
321 | wait_one_cycle(); | |
322 | if(!read) /* nothing on uart */ | |
323 | break; | |
324 | kind = read >> 1; | |
325 | if(kind == 1) | |
326 | state = MASTER_WAIT_FOR_PROPAGATE2; | |
327 | else /* kind == 2 is also bad here */ | |
328 | POST(BLOG_UART_BAD_KIND, kind); | |
329 | break; | |
330 | ||
331 | case MASTER_WAIT_FOR_PROPAGATE2: | |
332 | read = RX(); | |
333 | wait_one_cycle(); | |
334 | if(!read) /* nothing on uart */ | |
335 | break; | |
336 | instruction = read >> 1; /* we don't care about this */ | |
337 | state = MASTER_SEND_INSTRUCTION; | |
338 | break; | |
339 | ||
340 | case MASTER_WAIT_FOR_NEWS: | |
341 | read = RX(); | |
342 | wait_one_cycle(); | |
343 | if(!read) /* nothing on uart */ | |
344 | break; | |
345 | kind = read >> 1; | |
346 | if(ignore_next_rx) | |
347 | ignore_next_rx = 0; | |
348 | else if(kind == 1) /* propagation, ignore next byte */ | |
349 | ignore_next_rx = 1; | |
350 | else if(kind == 2) { /* ka-ching! */ | |
351 | state = MASTER_READ_NEWS_ADDRESS; | |
352 | } else | |
353 | POST(BLOG_UART_BAD_KIND, kind); | |
354 | break; | |
355 | ||
356 | case MASTER_READ_NEWS_ADDRESS: | |
357 | read = RX(); | |
358 | wait_one_cycle(); | |
359 | if(!read) /* nothing on uart */ | |
360 | break; | |
361 | /* we do not care about the address, we go read the data */ | |
362 | state = MASTER_READ_NEWS_DATA; | |
363 | break; | |
364 | ||
365 | case MASTER_READ_NEWS_DATA: | |
366 | read = RX(); | |
367 | wait_one_cycle(); | |
368 | if(!read) /* nothing on uart */ | |
369 | break; | |
370 | data = read >> 1; | |
371 | POST(BLOG_READ_NEWS_DATA, data); | |
372 | state = MASTER_SEND_INSTRUCTION; | |
373 | break; | |
374 | ||
375 | default: | |
376 | POST(BLOG_INVALID_STATE, state); | |
377 | break; | |
378 | } | |
379 | wait_one_cycle(); | |
380 | } | |
381 | KILL_UART(); | |
382 | } | |
383 | ||
384 | static int uarts[5]; | |
385 | static int ready[5]; | |
386 | static pthread_t threads[5]; | |
387 | ||
388 | void* spawn_thread(void* index) { | |
389 | switch((long)index) { | |
390 | case 0: | |
391 | master(uarts + 0, uarts + 4, ready + 4, ready + 0); | |
392 | break; | |
393 | case 1: | |
394 | worker(1, uarts + 1, uarts + 0, ready + 0, ready + 1); | |
395 | break; | |
396 | case 2: | |
397 | worker(2, uarts + 2, uarts + 1, ready + 1, ready + 2); | |
398 | break; | |
399 | case 3: | |
400 | worker(3, uarts + 3, uarts + 2, ready + 2, ready + 3); | |
401 | break; | |
402 | case 4: | |
403 | worker(4, uarts + 4, uarts + 3, ready + 3, ready + 4); | |
404 | break; | |
405 | default: | |
406 | printf("Spawned bad thread %ld\n", (long)index); | |
407 | } | |
408 | return NULL; | |
409 | } | |
410 | ||
411 | int main(void){ | |
412 | for(long i = 0 ; i < 5 ; i++) | |
413 | pthread_create(threads + i, NULL, spawn_thread, (void*)i); | |
414 | for(int i = 0 ; i < 5 ; i++) | |
415 | pthread_join(threads[i], NULL); | |
416 | // for(int i = 0; i < blog_n; i++) | |
417 | // display_post(i); | |
418 | return 0; | |
419 | } |