[Avida-SVN] r1142 - development/source/cpu

[barrick at myxo.css.msu.edu]

Author: barrick
Date: 2006-12-13 16:12:32 -0500 (Wed, 13 Dec 2006)
New Revision: 1142

Modified:
   development/source/cpu/cHardwareCPU.cc
Log:
Instructions assigned a "prob-fail" were not advancing the instruction pointer after they failed, resulting in a try-and-try-again repetiti
on until they were successful. Now the IP is advanced even if they fail.


Modified: development/source/cpu/cHardwareCPU.cc
===================================================================
--- development/source/cpu/cHardwareCPU.cc	2006-12-13 04:46:37 UTC (rev 1141)
+++ development/source/cpu/cHardwareCPU.cc	2006-12-13 21:12:32 UTC (rev 1142)
@@ -500,7 +500,7 @@
     const cInstruction& cur_inst = IP().GetInst();
     
     // Test if costs have been paid and it is okay to execute this now...
-    const bool exec = SingleProcess_PayCosts(ctx, cur_inst);
+    bool exec = SingleProcess_PayCosts(ctx, cur_inst);
 
     // Now execute the instruction...
     if (exec == true) {
@@ -509,8 +509,14 @@
       //       certain classes of instructions (namely divide instructions) @DMB
       const int addl_time_cost = m_inst_set->GetAddlTimeCost(cur_inst);
 
-      SingleProcess_ExecuteInst(ctx, cur_inst);
+      // Prob of exec (moved from SingleProcess_PayCosts so that we advance IP after a fail)
+      if ( m_inst_set->GetProbFail(cur_inst) > 0.0 ) 
+      {
+        exec = !( ctx.GetRandom().P(m_inst_set->GetProbFail(cur_inst)) );
+      }
       
+      if (exec == true) SingleProcess_ExecuteInst(ctx, cur_inst);
+      
       // Some instruction (such as jump) may turn m_advance_ip off.  Usually
       // we now want to move to the next instruction in the memory.
       if (m_advance_ip == true) IP().Advance();
@@ -556,10 +562,6 @@
     }
   }
   
-  // Prob of exec
-  if ( m_inst_set->GetProbFail(cur_inst) > 0.0 ){
-    return !( ctx.GetRandom().P(m_inst_set->GetProbFail(cur_inst)) );
-  }
 #endif
   return true;
 }