1/* { dg-do link } */
2/* { dg-require-effective-target sync_long_long_runtime } */
3/* { dg-options "" } */
4/* { dg-options "-march=pentium" { target { { i?86-*-* x86_64-*-* } && ia32 } } } */
5/* { dg-final { simulate-thread } } */
6
7
8#include <stdio.h>
9#include "simulate-thread.h"
10
11
12/* Testing load for atomicity is a little trickier.
13
14   Set up the atomic value so that it changes value after every instruction
15   is executed.
16
17   Simply alternating between 2 values wouldn't be sufficient since a load of
18   one part, followed by the load of the second part 2 instructions later would
19   appear to be valid.
20
21   set up a table of 16 values which change a bit in every byte of the value
22   each time, this will give us a 16 instruction cycle before repetition
23   kicks in, which should be sufficient to detect any issues.  Just to be sure,
24   we also change the table cycle size during execution.
25
26   The end result is that all loads should always get one of the values from
27   the table. Any other pattern means the load failed.  */
28
29unsigned long long ret;
30unsigned long long value = 0;
31unsigned long long result = 0;
32unsigned long long table[16] = {
330x0000000000000000,
340x1111111111111111,
350x2222222222222222,
360x3333333333333333,
370x4444444444444444,
380x5555555555555555,
390x6666666666666666,
400x7777777777777777,
410x8888888888888888,
420x9999999999999999,
430xAAAAAAAAAAAAAAAA,
440xBBBBBBBBBBBBBBBB,
450xCCCCCCCCCCCCCCCC,
460xDDDDDDDDDDDDDDDD,
470xEEEEEEEEEEEEEEEE,
480xFFFFFFFFFFFFFFFF
49};
50
51int table_cycle_size = 16;
52
53/* Return 0 if 'result' is a valid value to have loaded.  */
54int verify_result ()
55{
56  int x;
57  int found = 0;
58
59  /* Check entire table for valid values.  */
60  for (x = 0; x < 16 ; x++)
61    if (result == table[x])
62      {
63	found = 1;
64	break;
65      }
66
67  if (!found)
68    printf("FAIL: Invalid result returned from fetch\n");
69
70  return !found;
71}
72
73/* Iterate VALUE through the different valid values. */
74void simulate_thread_other_threads ()
75{
76  static int current = 0;
77
78  if (++current >= table_cycle_size)
79    current = 0;
80  value = table[current];
81}
82
83int simulate_thread_step_verify ()
84{
85  return verify_result ();
86}
87
88int simulate_thread_final_verify ()
89{
90  return verify_result ();
91}
92
93__attribute__((noinline))
94void simulate_thread_main()
95{
96  int x;
97
98  /* Execute loads with value changing at various cyclic values.  */
99  for (table_cycle_size = 16; table_cycle_size > 4 ; table_cycle_size--)
100    {
101      ret = __atomic_load_n (&value, __ATOMIC_SEQ_CST);
102      /* In order to verify the returned value (which is not atomic), it needs
103	 to be atomically stored into another variable and check that.  */
104      __atomic_store_n (&result, ret, __ATOMIC_SEQ_CST);
105
106      /* Execute the fetch/store a couple of times just to ensure the cycles
107         have a chance to be interesting.  */
108      ret = __atomic_load_n (&value, __ATOMIC_SEQ_CST);
109      __atomic_store_n (&result, ret, __ATOMIC_SEQ_CST);
110    }
111}
112
113int
114main()
115{
116  simulate_thread_main ();
117  simulate_thread_done ();
118  return 0;
119}
120