| /* { dg-do link } */ |
| /* { dg-require-effective-target sync_char_short } */ |
| /* { dg-final { simulate-thread } } */ |
| |
| |
| #include <stdio.h> |
| #include "simulate-thread.h" |
| |
| |
| /* Testing load for atomicity is a little trickier. |
| |
| Set up the atomic value so that it changes value after every instruction |
| is executed. |
| |
| Simply alternating between 2 values wouldn't be sufficient since a load of |
| one part, followed by the load of the second part 2 instructions later would |
| appear to be valid. |
| |
| set up a table of 16 values which change a bit in every byte of the value |
| each time, this will give us a 16 instruction cycle before repetition |
| kicks in, which should be sufficient to detect any issues. Just to be sure, |
| we also change the table cycle size during execution. |
| |
| The end result is that all loads should always get one of the values from |
| the table. Any other pattern means the load failed. */ |
| |
| unsigned short ret; |
| unsigned short value = 0; |
| unsigned short result = 0; |
| unsigned short table[16] = { |
| 0x0000, |
| 0x1111, |
| 0x2222, |
| 0x3333, |
| 0x4444, |
| 0x5555, |
| 0x6666, |
| 0x7777, |
| 0x8888, |
| 0x9999, |
| 0xAAAA, |
| 0xBBBB, |
| 0xCCCC, |
| 0xDDDD, |
| 0xEEEE, |
| 0xFFFF |
| }; |
| |
| int table_cycle_size = 16; |
| |
| /* Return 0 if 'result' is a valid value to have loaded. */ |
| int verify_result () |
| { |
| int x; |
| int found = 0; |
| |
| /* Check entire table for valid values. */ |
| for (x = 0; x < 16 ; x++) |
| if (result == table[x]) |
| { |
| found = 1; |
| break; |
| } |
| |
| if (!found) |
| printf("FAIL: Invalid result returned from fetch\n"); |
| |
| return !found; |
| } |
| |
| /* Iterate VALUE through the different valid values. */ |
| void simulate_thread_other_threads () |
| { |
| static int current = 0; |
| |
| if (++current >= table_cycle_size) |
| current = 0; |
| value = table[current]; |
| } |
| |
| int simulate_thread_step_verify () |
| { |
| return verify_result (); |
| } |
| |
| int simulate_thread_final_verify () |
| { |
| return verify_result (); |
| } |
| |
| __attribute__((noinline)) |
| void simulate_thread_main() |
| { |
| int x; |
| |
| /* Execute loads with value changing at various cyclic values. */ |
| for (table_cycle_size = 16; table_cycle_size > 4 ; table_cycle_size--) |
| { |
| ret = __atomic_load_n (&value, __ATOMIC_SEQ_CST); |
| /* In order to verify the returned value (which is not atomic), it needs |
| to be atomically stored into another variable and check that. */ |
| __atomic_store_n (&result, ret, __ATOMIC_SEQ_CST); |
| |
| /* Execute the fetch/store a couple of times just to ensure the cycles |
| have a chance to be interesting. */ |
| ret = __atomic_load_n (&value, __ATOMIC_SEQ_CST); |
| __atomic_store_n (&result, ret, __ATOMIC_SEQ_CST); |
| } |
| } |
| |
| int |
| main() |
| { |
| simulate_thread_main (); |
| simulate_thread_done (); |
| return 0; |
| } |