src/edu/berkeley/fleet/interpreter/Outbox.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.api.Instruction;
   5
   6 public class Outbox extends InstructionBenkoBox {
   7
   8     /** are we ready to accept another item from the ship? */
   9     private boolean readyForDataFromShip = false;
  10     private boolean haveDataFromShip     = false;
  11
  12     /** data which has been presented by the ship and is waiting to depart */
  13     private long    itemPresentedByShip;
  14
  15     /** number of tokens queued on the trigger input */
  16     private int     triggersReceived = 0;
  17
  18     /** the latched value */
  19     private long register;
  20
  21     public boolean isInbox() { return false; }
  22     public boolean isOutbox() { return true; }
  23     public Outbox(InterpreterShip ship, String name) { this(ship, name, new String[] { "" }); }
  24     public Outbox(InterpreterShip ship, String name, String[] ports) { super(ship, name, ports); }
  25
  26     protected final boolean service(Instruction.Executable instruction) {
  27
  28         // if no instruction waiting, do nothing
  29         if (instruction == null) return false;
  30
  31         // check firing conditions
  32         if (instruction.tokenIn && triggersReceived <= 0) return false;
  33         if (instruction.dataIn) {
  34             if (!haveDataFromShip) { readyForDataFromShip = true; return false; }
  35         }
  36
  37         // consume trigger
  38         if (instruction.tokenIn) triggersReceived--;
  39
  40         // consume item
  41         if (instruction.dataIn) {
  42             haveDataFromShip = false;
  43             if (instruction.latch)
  44                 register = itemPresentedByShip;
  45         }
  46
  47         if (instruction.dataOut) {
  48
  49             // if item to be transmitted, send it
  50             new Packet(getInterpreter(), this, register, (InterpreterDestination)instruction.dest).send();
  51             if (instruction.tokenOut)
  52                 throw new RuntimeException("outboxes may not send acks!");
  53
  54         } else if (instruction.tokenOut) {
  55
  56             // if no item was sent, we might still send an ack
  57             new Packet(getInterpreter(), this, 0, (InterpreterBenkoBox)instruction.dest).send();
  58         }
  59
  60         return true;
  61     }
  62
  63     public final boolean readyForDataFromShip() { return readyForDataFromShip; }
  64     public       void addDataFromShip(long data) { addItemFromShip(data); }
  65     public       void addDataFromFabric(Packet packet) { triggersReceived++; }
  66
  67     /** subclass invokes this to add an item from the ship */
  68     protected final void addItemFromShip(long data) {
  69         if (!readyForDataFromShip)
  70             throw new RuntimeException("tried to add an item to an outbox which was not ready!  you have a buggy ship!");
  71         readyForDataFromShip = false;
  72         haveDataFromShip = true;
  73         itemPresentedByShip = data;
  74     }
  75
  76     void shutdown() {
  77         if (haveDataFromShip)
  78             Log.println(ANSI.red(" WARNING: you left a value ("+itemPresentedByShip+") on outbox port " + this));
  79         if (triggersReceived > 0)
  80             Log.println(ANSI.red(" WARNING: you left a token on the trigger input to port " + this));
  81         super.shutdown(false);
  82     }
  83
  84 }