1 files changed, 108 insertions, 0 deletions
diff --git a/testsuite/vests/vhdl-ams/ashenden/compliant/digital-modeling/scheduler.vhd b/testsuite/vests/vhdl-ams/ashenden/compliant/digital-modeling/scheduler.vhd
new file mode 100644
index 0000000..9309901
--- /dev/null
+++ b/testsuite/vests/vhdl-ams/ashenden/compliant/digital-modeling/scheduler.vhd
@@ -0,0 +1,108 @@
+
+-- Copyright (C) 2002 Morgan Kaufmann Publishers, Inc
+
+-- This file is part of VESTs (Vhdl tESTs).
+
+-- VESTs is free software; you can redistribute it and/or modify it
+-- under the terms of the GNU General Public License as published by the
+-- Free Software Foundation; either version 2 of the License, or (at
+-- your option) any later version. 
+
+-- VESTs is distributed in the hope that it will be useful, but WITHOUT
+-- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+-- FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+-- for more details. 
+
+-- You should have received a copy of the GNU General Public License
+-- along with VESTs; if not, write to the Free Software Foundation,
+-- Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
+
+entity scheduler is
+end entity scheduler;
+
+
+architecture test of scheduler is
+
+  constant scheduling_delay : delay_length := 5 ns;
+
+  subtype request_type is natural range 0 to 20;
+  type server_status_type is (ready, busy);
+
+  signal first_priority_request,
+         first_normal_request,
+         reset_request : request_type := 0;
+  signal functional_request, equivalent_request : request_type;
+  signal priority_waiting : boolean := false;
+  signal server_status : server_status_type := busy;
+
+begin
+
+  functional_scheduler : block is
+    port ( request : out request_type );
+    port map ( request => functional_request );
+  begin
+
+    -- code from book
+
+    scheduler :
+      request <= first_priority_request after scheduling_delay
+                   when priority_waiting and server_status = ready else
+                 first_normal_request after scheduling_delay
+                   when not priority_waiting and server_status = ready else
+                 unaffected
+                   when server_status = busy else
+                 reset_request after scheduling_delay;
+
+    -- end code from book
+
+  end block functional_scheduler;
+
+  --------------------------------------------------
+
+  equivalent_scheduler : block is
+    port ( request : out request_type );
+    port map ( request => equivalent_request );
+  begin
+
+    -- code from book
+
+    scheduler : process is
+    begin
+      if priority_waiting and server_status = ready then
+        request <= first_priority_request after scheduling_delay;
+      elsif not priority_waiting and server_status = ready then
+        request <= first_normal_request after scheduling_delay;
+      elsif server_status = busy then
+        null;
+      else
+        request <= reset_request after scheduling_delay;
+      end if;
+      wait on first_priority_request, priority_waiting, server_status,
+              first_normal_request, reset_request;
+    end process scheduler;
+
+    -- end code from book
+
+  end block equivalent_scheduler;
+
+  --------------------------------------------------
+
+  stimulus : process is
+  begin
+    first_priority_request <= 10;	wait for 20 ns;
+    first_normal_request <= 5;		wait for 20 ns;
+    server_status <= ready;		wait for 20 ns;
+    server_status <= busy;		wait for 20 ns;
+    priority_waiting <= true;		wait for 20 ns;
+    server_status <= ready;		wait for 20 ns;
+    first_normal_request <= 7;		wait for 20 ns;
+    first_priority_request <= 12;	wait for 20 ns;
+
+    wait;
+  end process stimulus;
+
+  verifier :
+  assert functional_request = equivalent_request
+    report "Functional and equivalent models give different results";
+
+end architecture test;