50 lines
1 KiB
Plaintext
50 lines
1 KiB
Plaintext
(* Ressource allocator for two clients, 0 and 1 *)
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(* ri means that client i asks for the resource. *)
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(* gi means that client i was granted the resource. *)
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(* Security property: not (r0 & r1) *)
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(* Liveness property (expressed in LTL): G (ri => F gi) *)
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node alloc(r0 : bool; r1 : bool) returns (g0 : bool; g1 : bool)
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let
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automaton
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state IDLE0
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do g0 = false;
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g1 = false;
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unless r0 then ALLOC0 | (r1 & not r0) then ALLOC1
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state IDLE1
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do g0 = false;
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g1 = false;
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unless r1 then ALLOC1 | (r0 & not r1) then ALLOC0
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state ALLOC0
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do g0 = true;
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g1 = false;
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unless (not r0) then IDLE1
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state ALLOC1
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do g0 = false;
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g1 = true;
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unless (not r1) then IDLE0
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end;
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tel
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node main() returns (g0,g1:bool)
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var r0,r1:bool;
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let
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r0 = false fby not r0;
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r1 = false fby false fby true fby r1;
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(g0,g1) = alloc(r0,r1);
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tel
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(* CHECK main_assert *)
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node main_assert() returns (ok:bool)
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var g0,g1:bool;
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let
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(g0,g1) = main();
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ok = not (g0 & g1);
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tel
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