1 package edu.berkeley.fleet.loops;
4 import edu.berkeley.fleet.two.*;
5 import edu.berkeley.fleet.api.*;
6 import edu.berkeley.fleet.api.Instruction.*;
7 import edu.berkeley.fleet.api.Instruction.Set;
8 import edu.berkeley.fleet.api.Instruction.Set.*;
9 import static edu.berkeley.fleet.util.BitManipulations.*;
13 * A helper class for building loops of instructions.
15 * This class abstracts away:
16 * - The maximum size of a loop
17 * - The maximum length of a "one shot" instruction sequence
18 * - The looping/oneshot bit
19 * - The outer loop counter
20 * - The inner loop counter (opportunities to use it are auto-detected)
22 * It also performs various optimizations and provides a more
23 * convenient way of managing the predicate/interruptible fields.
25 * To get the most compact coding, the components of a Move should be
26 * performed in this order when possible, with no intervening commands:
34 public class LoopFactory {
36 public final Dock dock;
37 public final String friendlyName;
38 public final int count;
39 public final boolean torpedoable;
41 private final Context ctx;
42 private LoopFactory next = null;
43 private ArrayList<Instruction> instructions = new ArrayList<Instruction>();
47 * @arg dock the dock at which to execute the instructions
48 * @arg friendlyName a descriptive string for debugging the compiler
49 * @arg prev a loop for which this is the successor loop (if any)
50 * @arg count the number of times to execute this loop; <tt>0</tt> means continue until torpedoed
52 public LoopFactory(Context ctx, Dock dock, int count) {
53 this(ctx, dock, count, count==0, dock.toString(), null);
55 public LoopFactory(Context ctx, Dock dock, int count, boolean torpedoable) {
56 this(ctx, dock, count, torpedoable, dock.toString(), null);
58 public LoopFactory(Context ctx, Dock dock, int count, String friendlyName) {
59 this(ctx, dock, count, count==0, friendlyName);
61 public LoopFactory(Context ctx, Dock dock, int count, boolean torpedoable, String friendlyName) {
62 this(ctx, dock, count, torpedoable, friendlyName, null);
64 private LoopFactory(Context ctx, Dock dock, int count, boolean torpedoable, String friendlyName, LoopFactory prev) {
68 if (count==0 && !torpedoable)
69 throw new RuntimeException("count==0 loops must be torpedoable");
70 this.torpedoable = torpedoable;
71 this.friendlyName = friendlyName;
72 ctx.loopFactories.add(this);
73 if (ctx.startupLoopFactories.get(dock) == null)
74 ctx.startupLoopFactories.put(dock, this);
76 if (prev.getNext() != null) throw new RuntimeException();
81 public LoopFactory makeNext(int new_count) { return makeNext(new_count, null); }
82 public LoopFactory makeNext(int new_count, String newFriendlyName) { return makeNext(new_count, new_count==0, newFriendlyName); }
83 public LoopFactory makeNext(int new_count, boolean newTorpedoable) { return makeNext(new_count, newTorpedoable, null); }
84 public LoopFactory makeNext(int new_count, boolean newTorpedoable, String newFriendlyName) {
85 if (next != null) throw new RuntimeException("loop already has a successor");
86 return new LoopFactory(ctx, dock, new_count, newTorpedoable, newFriendlyName, this);
88 public LoopFactory getNext() { return next; }
89 private void setNext(LoopFactory next) {
90 if (this.next != null) throw new RuntimeException("attempt to setNext() twice");
95 // Building Loops //////////////////////////////////////////////////////////////////////////////
97 Predicate predicate = Predicate.Default;
98 boolean pending_interruptible = false;
99 boolean pending_recvToken = false;
100 boolean pending_recvOrCollect = false;
101 boolean pending_latchData = false;
102 boolean pending_latchPath = false;
103 boolean pending_sendToken = false;
104 Path pending_path = null;
106 void flush_pending() { flush_pending(false); }
107 void flush_pending(boolean pending_dataOut) {
108 if (!pending_recvToken &&
109 !pending_recvOrCollect &&
110 !pending_sendToken &&
112 if (pending_interruptible)
113 throw new RuntimeException("abortLoopIfTorpedoPresent() must be followed immediately by a Move");
115 instructions.add(new Move(dock,
117 pending_interruptible,
118 pending_path==null ? null : pending_path,
120 pending_recvOrCollect,
126 pending_interruptible = false;
127 pending_recvToken = false;
128 pending_recvOrCollect = false;
129 pending_latchData = false;
130 pending_latchPath = false;
131 pending_sendToken = false;
135 public void interruptibleNop() {
137 instructions.add(new Move(dock,
149 /** sets the predicate which will be applied to subsequent instructions, or null for the default predicate */
150 public void setPredicate(Predicate p) {
151 if (p==null) p = Predicate.Default;
152 if (predicate==p) return;
157 /** must be followed immediately by a move-based instruction */
158 public void abortLoopIfTorpedoPresent() {
161 throw new RuntimeException("invocation of abortLoopIfTorpedoPresent() in a non-torpedoable LoopFactory");
162 pending_interruptible = true;
166 public void recvToken() {
167 if (pending_recvToken || pending_recvOrCollect || pending_sendToken) flush_pending();
168 pending_recvToken = true;
171 /** [inboxes only] */
172 public void recv(boolean latchData, boolean latchPath) {
173 if (!dock.isInputDock()) throw new RuntimeException("recv() may only be used at input docks");
174 if (pending_recvOrCollect || pending_sendToken) flush_pending();
175 pending_recvOrCollect = true;
176 pending_latchData = latchData;
177 pending_latchPath = latchPath;
180 /** [outboxes only], will fuse with previous instruction if it was a recvToken() */
181 public void collect(boolean latchData, boolean latchPath) {
182 if (!dock.isOutputDock()) throw new RuntimeException("collect() may only be used at output docks");
183 if (pending_recvOrCollect || pending_sendToken) flush_pending();
184 pending_recvOrCollect = true;
185 pending_latchData = latchData;
186 pending_latchPath = latchPath;
189 /** [either], will fuse with previous instruction if it was a recvToken(), recv(), or collect() */
190 public void sendToken(Destination dest) { sendToken(dest, null); }
191 public void sendToken(Destination dest, BitVector signal) {
192 if (pending_sendToken) flush_pending();
193 pending_path = dock.getPath(dest, signal);
194 pending_sendToken = true;
197 /** [inboxes only], will fuse with previous instruction if it was a sendToken() */
198 public void deliver() {
199 if (!dock.isInputDock()) throw new RuntimeException("deliver() may only be used at input docks");
203 /** [inboxes only], will fuse with previous instruction if it was a sendToken() */
204 public void flush() {
205 if (!dock.isInputDock()) throw new RuntimeException("flush() may only be used at input docks");
207 instructions.add(new Instruction.Flush(dock, predicate));
210 /** [outboxes only], will fuse with previous instruction if it was a sendToken() */
211 public void sendWord(Destination dest) { sendWord(dest, null); }
212 public void sendWord(Destination dest, BitVector signal) {
213 if (!dock.isOutputDock()) throw new RuntimeException("sendWord() may only be used at output docks");
214 if (pending_sendToken) flush_pending();
215 pending_path = dock.getPath(dest, signal);
219 /** sets the data latch to a literal value */
220 public void literal(BitVector literal) {
221 // FIXME: code duplication here
222 // FEATURE: be more intelligent here to avoid shifts if possible?
224 while(counter < dock.getShip().getFleet().getWordWidth()) counter += ctx.fleet.getShiftWidth();
226 BitVector temp = new BitVector(dock.getShip().getFleet().getShiftWidth());
227 for(int i=counter-1; i>=counter-ctx.fleet.getShiftWidth(); i--)
228 if (i<literal.length())
229 temp.set(i-(counter-ctx.fleet.getShiftWidth()), literal.get(i));
230 instructions.add(new Shift(dock, predicate, temp));
231 counter -= ctx.fleet.getShiftWidth();
235 /** sets the data latch to a literal value */
236 public void literal(long literal) {
238 if (((FleetTwoFleet)ctx.fleet).isSmallEnoughToFit(literal)) {
239 instructions.add(new Instruction.Set(dock, predicate, SetDest.DataLatch, literal));
243 while(counter < dock.getShip().getFleet().getWordWidth()) { extra++; counter += ctx.fleet.getShiftWidth(); }
244 warn("literal " + literal + " requires " + extra + " instructions");
246 instructions.add(new Shift(dock, predicate,
247 new BitVector(dock.getShip().getFleet().getWordWidth())
248 .set(getField(counter-1, counter-ctx.fleet.getShiftWidth(), literal))));
249 counter -= ctx.fleet.getShiftWidth();
254 /** sets the flags */
255 public void setFlags(Instruction.Set.FlagFunction newFlagA, Instruction.Set.FlagFunction newFlagB) {
257 instructions.add(new Instruction.Set(dock,
263 /** abort the loop immediately (if predicate is met) and invoke the successor loop */
264 public void abort() {
266 instructions.add(new Instruction.Set(dock,
268 SetDest.OuterLoopCounter,
272 public void abortAndInvoke(LoopFactory lf) {
273 throw new RuntimeException("not implemented");
276 // Emitting Code //////////////////////////////////////////////////////////////////////////////
280 // FEATURE: find loops of 1 instruction, use ILC
281 // FEATURE: find sequences of >2 adjacent identical instructions, replace with use of ILC
282 // FEATURE: after optimizing, find single-instruction loops, replace with use of ILC
283 // FEATURE: consider doing loop unrolling if two copies of the loop fit in the instruction buffer...
284 // FEATURE: clever instruction re-oredering?
288 * The code emitted by this method makes the following assumptions:
290 * - The instructions emitted are dispatched in order
291 * - At the time of dispatch, the dock must be pre-quiescent.
294 public void emit(ArrayList<Instruction> ic) {
295 emit(ic, dock.getInstructionFifoSize());
297 private void emit(ArrayList<Instruction> ic, int capacity) {
301 // the number of instructions after and including the first blocking instruction
302 int numInstructionsNotIncludingNonblockingPrefix = 0;
304 boolean blockingInstructionEncountered = false;
306 // Set the OLC (it might previously have been zero)
307 ic.add(new Set(dock, Predicate.IgnoreFlagD, SetDest.OuterLoopCounter, count==0 ? 1 : count));
309 ic.add(new Instruction.Head(dock));
312 for(Instruction i : instructions) {
313 if (i instanceof Move && (((Move)i).tokenIn || ((Move)i).dataIn))
314 blockingInstructionEncountered = true;
315 if (blockingInstructionEncountered)
316 numInstructionsNotIncludingNonblockingPrefix++;
322 if (numInstructionsNotIncludingNonblockingPrefix > capacity)
323 throw new RuntimeException("instruction sequence is too long for instruction fifo at " + dock);
326 ic.add(new Instruction.Set(dock, Predicate.Default, SetDest.OuterLoopCounter, SetSource.Decrement));
327 if (blockingInstructionEncountered)
328 numInstructionsNotIncludingNonblockingPrefix++;
333 ic.add(new Instruction.Abort(dock, Predicate.FlagD));
334 if (ctx.autoflush && next==null && dock.isInputDock())
335 ic.add(new Instruction.Flush(dock, Predicate.FlagD));
337 // FIXME: need to somehow deal with count!=0 loops that are
338 // torpedoable; they need to wait for a torpedo to arrive
339 // after exhausting their count.
342 ic.add(new Instruction.Tail(dock));
343 if (loopSize > capacity)
344 throw new RuntimeException("instruction loop is too long for instruction fifo");
348 if (count != 1) throw new RuntimeException("no support for successor loops when count!=1 yet");
349 next.emit(ic, capacity - loopSize);
353 void warn(String warning) {
354 System.err.println("warning: " + warning);
357 // Helpers //////////////////////////////////////////////////////////////////////////////
359 public void recvWord() { recv(true, false); }
360 public void recvPath() { recv(false, true); }
361 public void recvPacket() { recv(true, true); }
362 public void collectWord() { collect(true, false); }
363 public void collectPath() { collect(false, true); }
364 public void collectPacket() { collect(true, true); }