src/edu/berkeley/fleet/interpreter/InstructionPump.java

   1 package edu.berkeley.fleet.interpreter;
   2 import edu.berkeley.sbp.util.ANSI;
   3 import edu.berkeley.fleet.api.*;
   4 import edu.berkeley.fleet.doc.*;
   5 import edu.berkeley.fleet.api.Instruction;
   6
   7 import java.util.*;
   8
   9 /** anything that has a source (instruction horn) address on the switch fabric */
  10 abstract class InstructionPump extends InterpreterPump {
  11
  12     public int clogged = 0;
  13
  14     /** the currently executing instruction */
  15     private Instruction.Executable executing = null;
  16
  17     /** all instructions waiting to be executed (excludes executing) */
  18     private Queue<Instruction.Executable> instructions = new LinkedList<Instruction.Executable>();
  19
  20     /** count of how many "standing instruction only" kills remain to be executed */
  21     private int killNextStandingInstruction = 0;
  22
  23     InstructionPump(InterpreterShip ship, String name, String[] ports) {
  24         super(ship, name, ports);
  25     }
  26
  27     public void kill(int count, boolean killOnlyStandingInstructions) {
  28         if (count==0) return;
  29         if (!killOnlyStandingInstructions) {
  30             if (executing != null) { executing = null; count--; }
  31             for(;count > 0;count--) {
  32                 if (instructions.size()==0)
  33                     throw new RuntimeException("deadlocked " + this + " by killing too many instructions");
  34                 instructions.remove();
  35             }
  36         } else {
  37             if (count != 1) throw new RuntimeException("this should never happen");
  38             this.killNextStandingInstruction++;
  39         }
  40     }
  41
  42     /** an instruction arrives from the instruction horn */
  43     void addInstruction(Instruction.Executable instr) {
  44         if (killNextStandingInstruction > 0) { /* FIXME technically we should refuse to take the next instruction here */ }
  45         instructions.add(instr);
  46     }
  47
  48     protected void shutdown(boolean leaveAsInbox) {
  49         if (!(executing != null || instructions.size() > 0)) return;
  50         Log.println(ANSI.red(" WARNING: you left instructions on the instruction queue of port " +
  51                              this + "; they are:"));
  52         if (executing != null)
  53             Log.println("   " + executing);
  54         for(Instruction.Executable i : instructions)
  55             Log.println("   " + i);
  56     }
  57
  58     // interface to subclass ///////////////////////////////////////////////////////////////////////
  59
  60     /** this will be invoked periodically; should return true to "consume" an instruction, false to leave it executing */
  61     protected abstract boolean service(Instruction.Executable instr);
  62
  63     protected final void service() {
  64         if (executing == null)
  65             if (instructions.size() > 0)
  66                 executing = instructions.remove();
  67             else
  68                 return;
  69
  70         if (executing != null && killNextStandingInstruction>0 && executing.isStanding()) {
  71             executing = null;
  72             killNextStandingInstruction--;
  73             return;
  74         }
  75
  76         boolean ret = service(executing);
  77         if (!ret) return;
  78         if (executing.isRequeueing()) {
  79             executing = executing.decrementCount();
  80             if (executing != null)
  81                 addInstruction(executing);
  82             executing = null;
  83
  84         } else {
  85             if (executing != null && !executing.isStanding())
  86                 executing = executing.decrementCount();
  87         }
  88     }
  89
  90
  91 }