src/edu/berkeley/fleet/InstructionPort.java

   1 package edu.berkeley.fleet;
   2
   3 import java.util.*;
   4
   5 /** anything that has a source (instruction horn) address on the switch fabric */
   6 public abstract class InstructionPort extends Port {
   7
   8     /** the currently executing instruction */
   9     Instruction currentlyExecuting = null;
  10
  11     /** all instructions waiting to be executed (excludes currentlyExecuting) */
  12     Queue<Instruction> instructions = new LinkedList<Instruction>();
  13
  14     /** the count field of currentlyExecuting, taking into account actions already performed */
  15     int currentlyExecutingCount;
  16
  17     InstructionPort(Ship ship, String name) {
  18         super(ship, name);
  19     }
  20
  21     /** an instruction arrives from the instruction horn */
  22     void addInstruction(Instruction instr) {
  23         if (currentlyExecuting != null && currentlyExecuting.count == Integer.MAX_VALUE) {
  24             currentlyExecuting = null;
  25             currentlyExecutingCount = 0;
  26         }
  27         if (currentlyExecuting == null) {
  28             currentlyExecuting = instr;
  29             currentlyExecutingCount = currentlyExecuting.count;
  30         } else {
  31             instructions.add(instr);
  32         }
  33     }
  34
  35     protected void shutdown(boolean leaveAsInbox) {
  36         if (leaveAsInbox && DataInbox.defaultInstruction != null) {
  37             if (currentlyExecuting == null) {
  38                 Log.println(Log.red(" WARNING: you did not leave a standing move on inbox-port " + this));
  39                 return;
  40             }
  41             /*
  42             if (currentlyExecuting.count != Integer.MAX_VALUE
  43                 || currentlyExecuting.dataIn != Instruction.IgnoreCopyTake.TAKE
  44                 || currentlyExecuting.ack
  45                 || currentlyExecuting.trigger
  46                 || !currentlyExecuting.dataOut) {
  47                 Log.println(Log.red(" WARNING: you did not leave the correct standing move on inbox-port " + this)+
  48                             "\n            found:    " + currentlyExecuting
  49                             );
  50                 return;
  51             }
  52             */
  53             currentlyExecuting = null;
  54         }
  55         if (currentlyExecuting != null || instructions.size() > 0) {
  56             Log.println(Log.red(" WARNING: you left instructions on the instruction queue of port " +
  57                                 this + "; they are:"));
  58             if (currentlyExecuting != null)
  59                 Log.println("   " + currentlyExecuting);
  60             for(Instruction i : instructions)
  61                 Log.println("   " + i);
  62         }
  63     }
  64
  65     // interface to subclass ///////////////////////////////////////////////////////////////////////
  66
  67     /** this will be invoked periodically; should return true to "consume" an instruction, false to leave it executing */
  68     protected abstract boolean service(Instruction instr);
  69
  70     protected final void service() {
  71         if (currentlyExecutingCount <= 0)
  72             currentlyExecuting = null;
  73         if (currentlyExecuting == null && instructions.size() > 0) {
  74             currentlyExecuting = instructions.remove();
  75             currentlyExecutingCount = currentlyExecuting.count;
  76         }
  77         boolean ret = service(currentlyExecuting);
  78         if (ret && currentlyExecuting != null && currentlyExecutingCount != Integer.MAX_VALUE)
  79             currentlyExecutingCount--;
  80     }
  81
  82
  83 }