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.ies44.*;
   5 import edu.berkeley.fleet.api.Instruction;
   6
   7 public class Outbox extends InstructionBenkoBox {
   8
   9     /** are we ready to accept another item from the ship? */
  10     private boolean readyForDataFromShip = false;
  11     private boolean haveDataFromShip     = false;
  12
  13     /** data which has been presented by the ship and is waiting to depart */
  14     private long    itemPresentedByShip;
  15
  16     /** number of tokens queued on the trigger input */
  17     private int     triggersReceived = 0;
  18
  19     /** the latched value */
  20     private long register;
  21
  22     public boolean isInbox() { return false; }
  23     public boolean isOutbox() { return true; }
  24     public Outbox(InterpreterShip ship, String name) { this(ship, name, new String[] { "" }); }
  25     public Outbox(InterpreterShip ship, String name, String[] ports) { super(ship, name, ports); }
  26
  27     protected final boolean service(Instruction.Executable instruction) {
  28
  29         // if no instruction waiting, do nothing
  30         if (instruction == null) return false;
  31
  32         // check firing conditions
  33         if (instruction.tokenIn && triggersReceived <= 0) return false;
  34         if (instruction.dataIn) {
  35             if (!haveDataFromShip) { readyForDataFromShip = true; return false; }
  36         }
  37
  38         // consume trigger
  39         if (instruction.tokenIn) triggersReceived--;
  40
  41         // consume item
  42         if (instruction.dataIn) {
  43             haveDataFromShip = false;
  44             if (instruction.latch)
  45                 register = itemPresentedByShip;
  46         }
  47
  48         if (instruction.dataOut) {
  49
  50             // if item to be transmitted, send it
  51             InterpreterDestination dest = (InterpreterDestination)instruction.dest;
  52             if (instruction.dataOutDest) {
  53                 long bits = BitManipulations.getField(InstructionEncoder.WIDTH_WORD-1,
  54                                                       InstructionEncoder.WIDTH_WORD-InstructionEncoder.WIDTH_DEST_ADDR,
  55                                                       register);
  56                 dest = (InterpreterDestination)(((Interpreter)getInterpreter()).iie.getDestByAddr(bits));
  57             }
  58             new Packet(getInterpreter(), this, register, dest).send();
  59             if (instruction.tokenOut)
  60                 throw new RuntimeException("outboxes may not send acks!");
  61
  62         } else if (instruction.tokenOut) {
  63
  64             // if no item was sent, we might still send an ack
  65             new Packet(getInterpreter(), this, 0, (InterpreterDestination)instruction.dest).send();
  66         }
  67
  68         return true;
  69     }
  70
  71     public final boolean readyForDataFromShip() { return readyForDataFromShip; }
  72     public       void addDataFromShip(long data) { addItemFromShip(data); }
  73     public       void addDataFromFabric(Packet packet) { triggersReceived++; }
  74
  75     /** subclass invokes this to add an item from the ship */
  76     protected final void addItemFromShip(long data) {
  77         if (!readyForDataFromShip)
  78             throw new RuntimeException("tried to add an item to an outbox which was not ready!  you have a buggy ship!");
  79         readyForDataFromShip = false;
  80         haveDataFromShip = true;
  81         itemPresentedByShip = data;
  82     }
  83
  84     void shutdown() {
  85         if (haveDataFromShip)
  86             Log.println(ANSI.red(" WARNING: you left a value ("+itemPresentedByShip+") on outbox port " + this));
  87         if (triggersReceived > 0)
  88             Log.println(ANSI.red(" WARNING: you left a token on the trigger input to port " + this));
  89         super.shutdown(false);
  90     }
  91
  92 }