X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=formal-model%2Fooomem-two-writes%2Fmem.spin;h=1eb51c9893c8dc5a38e6f791257e96a8f9d79845;hb=b245dd5c50e7b1c66073d41edc44a09dc1b6c9f2;hp=828ff4a5d9245e51c3ba529af0ff4c0189caefc8;hpb=4b8839f157982c717e307a2045428d3582185b11;p=urcu.git

diff --git a/formal-model/ooomem-two-writes/mem.spin b/formal-model/ooomem-two-writes/mem.spin
index 828ff4a..1eb51c9 100644
--- a/formal-model/ooomem-two-writes/mem.spin
+++ b/formal-model/ooomem-two-writes/mem.spin
@@ -1,5 +1,18 @@
 /*
- * mem.spin: Promela code to validate memory barriers with OOO memory.
+ * mem.spin: Promela code to validate memory barriers with out-of-order memory
+ * and out-of-order instruction scheduling.
+ *
+ * Algorithm verified :
+ *
+ * alpha = 0;
+ * beta = 0;
+ *
+ * Process A                  Process B
+ * alpha = 1;                 beta = 1;
+ * mb();                      mb();
+ * x = beta;                  y = alpha;
+ *
+ * if x = 1, then y = 1 when read.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -21,48 +34,22 @@
 /* Promela validation variables. */
 
 /*
- * Produced process data flow. Updated after each instruction to show which
- * variables are ready. Assigned using SSA (static single assignment) (defuse
- * analysis must be done on the program to map "real" variables to single define
- * followed by use). Using one-hot bit encoding per variable to save state
- * space.  Used as triggers to execute the instructions having those variables
- * as input.
- */
-
-#define PRODUCE_TOKENS(state, bits)	\
-	state = (state) | (bits)
-
-/* All bits must be active to consume. All notbits must be inactive. */
-/* Consuming a token does not clear it, it just waits for it. */
-#define CONSUME_TOKENS(state, bits, notbits)				\
-	((!((state) & (notbits))) && ((state) & (bits)) == (bits))
-
-#define CLEAR_TOKENS(state, bits)	\
-	state = (state) & ~(bits)
-
-/*
- * Bit encoding, proc_one_produced :
+ * Produced process control and data flow. Updated after each instruction to
+ * show which variables are ready. Using one-hot bit encoding per variable to
+ * save state space. Used as triggers to execute the instructions having those
+ * variables as input. Leaving bits active to inhibit instruction execution.
+ * Scheme used to make instruction disabling and automatic dependency fall-back
+ * automatic.
  */
 
-#define P1_PROD_NONE	(1 << 0)
-
-#define P1_WRITE	(1 << 1)
-#define P1_WMB		(1 << 2)
-#define P1_SYNC_CORE	(1 << 3)
-#define P1_RMB		(1 << 4)
-#define P1_READ		(1 << 5)
-
-int proc_one_produced;
-
-#define P2_PROD_NONE	(1 << 0)
+#define CONSUME_TOKENS(state, bits, notbits)			\
+	((!(state & (notbits))) && (state & (bits)) == (bits))
 
-#define P2_WRITE	(1 << 1)
-#define P2_WMB		(1 << 2)
-#define P2_SYNC_CORE	(1 << 3)
-#define P2_RMB		(1 << 4)
-#define P2_READ		(1 << 5)
+#define PRODUCE_TOKENS(state, bits)				\
+	state = state | (bits);
 
-int proc_two_produced;
+#define CLEAR_TOKENS(state, bits)				\
+	state = state & ~(bits)
 
 #define NR_PROCS 2
 
@@ -172,6 +159,20 @@ DECLARE_CACHED_VAR(byte, beta, 0);
 byte read_one = 2;
 byte read_two = 2;
 
+/*
+ * Bit encoding, proc_one_produced :
+ */
+
+#define P1_PROD_NONE	(1 << 0)
+
+#define P1_WRITE	(1 << 1)
+#define P1_WMB		(1 << 2)
+#define P1_SYNC_CORE	(1 << 3)
+#define P1_RMB		(1 << 4)
+#define P1_READ		(1 << 5)
+
+int proc_one_produced;
+
 active proctype test_proc_one()
 {
 	assert(get_pid() < NR_PROCS);
@@ -222,6 +223,21 @@ active proctype test_proc_one()
 	assert(!(read_one == 0 && read_two == 0));
 }
 
+
+/*
+ * Bit encoding, proc_two_produced :
+ */
+
+#define P2_PROD_NONE	(1 << 0)
+
+#define P2_WRITE	(1 << 1)
+#define P2_WMB		(1 << 2)
+#define P2_SYNC_CORE	(1 << 3)
+#define P2_RMB		(1 << 4)
+#define P2_READ		(1 << 5)
+
+int proc_two_produced;
+
 active proctype test_proc_two()
 {
 	assert(get_pid() < NR_PROCS);