forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
34 lines
694 B
34 lines
694 B
C LB+fencembonceonce+ctrlonceonce |
|
|
|
(* |
|
* Result: Never |
|
* |
|
* This litmus test demonstrates that lightweight ordering suffices for |
|
* the load-buffering pattern, in other words, preventing all processes |
|
* reading from the preceding process's write. In this example, the |
|
* combination of a control dependency and a full memory barrier are enough |
|
* to do the trick. (But the full memory barrier could be replaced with |
|
* another control dependency and order would still be maintained.) |
|
*) |
|
|
|
{} |
|
|
|
P0(int *x, int *y) |
|
{ |
|
int r0; |
|
|
|
r0 = READ_ONCE(*x); |
|
if (r0) |
|
WRITE_ONCE(*y, 1); |
|
} |
|
|
|
P1(int *x, int *y) |
|
{ |
|
int r0; |
|
|
|
r0 = READ_ONCE(*y); |
|
smp_mb(); |
|
WRITE_ONCE(*x, 1); |
|
} |
|
|
|
exists (0:r0=1 /\ 1:r0=1)
|
|
|