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 // FIXME: vet this to see if it is sensible
37 private boolean instructionFifoSizeCheckDisabled = false;
38 public void disableInstructionFifoOverflowCheck() { instructionFifoSizeCheckDisabled = true; }
40 public final Dock dock;
41 public final String friendlyName;
42 public final int count;
43 public final boolean torpedoable;
45 private final Context ctx;
46 private LoopFactory next = null;
47 private ArrayList<Instruction> instructions = new ArrayList<Instruction>();
51 * @arg dock the dock at which to execute the instructions
52 * @arg friendlyName a descriptive string for debugging the compiler
53 * @arg prev a loop for which this is the successor loop (if any)
54 * @arg count the number of times to execute this loop; <tt>0</tt> means continue until torpedoed
56 public LoopFactory(Context ctx, Dock dock, int count) {
57 this(ctx, dock, count, count==0, dock.toString(), null);
59 public LoopFactory(Context ctx, Dock dock, int count, boolean torpedoable) {
60 this(ctx, dock, count, torpedoable, dock.toString(), null);
62 public LoopFactory(Context ctx, Dock dock, int count, String friendlyName) {
63 this(ctx, dock, count, count==0, friendlyName);
65 public LoopFactory(Context ctx, Dock dock, int count, boolean torpedoable, String friendlyName) {
66 this(ctx, dock, count, torpedoable, friendlyName, null);
68 private LoopFactory(Context ctx, Dock dock, int count, boolean torpedoable, String friendlyName, LoopFactory prev) {
72 if (count==0 && !torpedoable)
73 throw new RuntimeException("count==0 loops must be torpedoable");
74 this.torpedoable = torpedoable;
75 this.friendlyName = friendlyName;
76 ctx.loopFactories.add(this);
77 if (ctx.startupLoopFactories.get(dock) == null)
78 ctx.startupLoopFactories.put(dock, this);
80 if (prev.getNext() != null) throw new RuntimeException();
85 public LoopFactory makeNext(int new_count) { return makeNext(new_count, null); }
86 public LoopFactory makeNext(int new_count, String newFriendlyName) { return makeNext(new_count, new_count==0, newFriendlyName); }
87 public LoopFactory makeNext(int new_count, boolean newTorpedoable, String newFriendlyName) {
88 if (next != null) throw new RuntimeException("loop already has a successor");
89 return new LoopFactory(ctx, dock, new_count, newTorpedoable, newFriendlyName, this);
91 public LoopFactory getNext() { return next; }
92 private void setNext(LoopFactory next) {
93 if (this.next != null) throw new RuntimeException("attempt to setNext() twice");
98 // Building Loops //////////////////////////////////////////////////////////////////////////////
100 Predicate predicate = Predicate.Default;
101 boolean pending_interruptible = false;
102 boolean pending_recvToken = false;
103 boolean pending_recvOrCollect = false;
104 boolean pending_latchData = false;
105 boolean pending_latchPath = false;
106 boolean pending_sendToken = false;
107 Path pending_path = null;
109 void flush_pending() { flush_pending(false); }
110 void flush_pending(boolean pending_dataOut) {
111 if (!pending_recvToken &&
112 !pending_recvOrCollect &&
113 !pending_sendToken &&
115 if (pending_interruptible)
116 throw new RuntimeException("abortLoopIfTorpedoPresent() must be followed immediately by a Move");
118 instructions.add(new Move(dock,
121 pending_interruptible,
122 pending_path==null ? null : pending_path,
124 pending_recvOrCollect,
130 pending_interruptible = false;
131 pending_recvToken = false;
132 pending_recvOrCollect = false;
133 pending_latchData = false;
134 pending_latchPath = false;
135 pending_sendToken = false;
139 public void interruptibleNop() {
141 instructions.add(new Move(dock,
154 /** sets the predicate which will be applied to subsequent instructions, or null for the default predicate */
155 public void setPredicate(Predicate p) {
156 if (p==null) p = Predicate.Default;
157 if (predicate==p) return;
162 /** must be followed immediately by a move-based instruction */
163 public void abortLoopIfTorpedoPresent() {
166 throw new RuntimeException("invocation of abortLoopIfTorpedoPresent() in a non-torpedoable LoopFactory");
167 pending_interruptible = true;
171 public void recvToken() {
172 if (pending_recvToken || pending_recvOrCollect || pending_sendToken) flush_pending();
173 pending_recvToken = true;
176 /** [inboxes only] */
177 public void recv(boolean latchData, boolean latchPath) {
178 if (!dock.isInputDock()) throw new RuntimeException("recv() may only be used at input docks");
179 if (pending_recvOrCollect || pending_sendToken) flush_pending();
180 pending_recvOrCollect = true;
181 pending_latchData = latchData;
182 pending_latchPath = latchPath;
185 /** [outboxes only], will fuse with previous instruction if it was a recvToken() */
186 public void collect(boolean latchData, boolean latchPath) {
187 if (!dock.isOutputDock()) throw new RuntimeException("collect() may only be used at output docks");
188 if (pending_recvOrCollect || pending_sendToken) flush_pending();
189 pending_recvOrCollect = true;
190 pending_latchData = latchData;
191 pending_latchPath = latchPath;
194 /** [either], will fuse with previous instruction if it was a recvToken(), recv(), or collect() */
195 public void sendToken(Destination dest) { sendToken(dest, null); }
196 public void sendToken(Destination dest, BitVector signal) {
197 if (pending_sendToken) flush_pending();
198 pending_path = dock.getPath(dest, signal);
199 pending_sendToken = true;
202 /** [inboxes only], will fuse with previous instruction if it was a sendToken() */
203 public void deliver() {
204 if (!dock.isInputDock()) throw new RuntimeException("deliver() may only be used at input docks");
208 /** [inboxes only], will fuse with previous instruction if it was a sendToken() */
209 public void flush() {
210 if (!dock.isInputDock()) throw new RuntimeException("flush() may only be used at input docks");
212 instructions.add(new Instruction.Flush(dock, count!=1, predicate));
215 /** [outboxes only], will fuse with previous instruction if it was a sendToken() */
216 public void sendWord(Destination dest) { sendWord(dest, null); }
217 public void sendWord(Destination dest, BitVector signal) {
218 if (!dock.isOutputDock()) throw new RuntimeException("sendWord() may only be used at output docks");
219 if (pending_sendToken) flush_pending();
220 pending_path = dock.getPath(dest, signal);
224 /** sets the data latch to a literal value */
225 public void literal(BitVector literal) {
226 // FIXME: code duplication here
227 // FIXME: be more intelligent here to avoid shifts if possible?
229 while(counter < dock.getShip().getFleet().getWordWidth()) counter += ctx.fleet.getShiftWidth();
231 BitVector temp = new BitVector(dock.getShip().getFleet().getShiftWidth());
232 for(int i=counter-1; i>=counter-ctx.fleet.getShiftWidth(); i--)
233 if (i<literal.length())
234 temp.set(i-(counter-ctx.fleet.getShiftWidth()), literal.get(i));
235 instructions.add(new Shift(dock, count!=1, predicate, temp));
236 counter -= ctx.fleet.getShiftWidth();
240 /** sets the data latch to a literal value */
241 public void literal(long literal) {
243 if (((FleetTwoFleet)ctx.fleet).isSmallEnoughToFit(literal)) {
244 instructions.add(new Instruction.Set(dock, count!=1, predicate, SetDest.DataLatch, literal));
248 while(counter < dock.getShip().getFleet().getWordWidth()) { extra++; counter += ctx.fleet.getShiftWidth(); }
249 warn("literal " + literal + " requires " + extra + " instructions");
251 instructions.add(new Shift(dock, count!=1, predicate,
252 new BitVector(dock.getShip().getFleet().getWordWidth())
253 .set(getField(counter-1, counter-ctx.fleet.getShiftWidth(), literal))));
254 counter -= ctx.fleet.getShiftWidth();
259 /** sets the flags */
260 public void setFlags(Instruction.Set.FlagFunction newFlagA, Instruction.Set.FlagFunction newFlagB) {
262 instructions.add(new Instruction.Set(dock,
269 // FIXME: what if we're using an ILC-loop?
270 /** abort the loop immediately (if predicate is met) and invoke the successor loop */
271 public void abort() {
273 instructions.add(new Instruction.Set(dock,
276 SetDest.OuterLoopCounter,
280 public void abortAndInvoke(LoopFactory lf) {
281 throw new RuntimeException("not implemented");
284 // Emitting Code //////////////////////////////////////////////////////////////////////////////
288 // FEATURE: find loops of 1 instruction, use ILC
289 // FEATURE: find sequences of >2 adjacent identical instructions, replace with use of ILC
290 // FEATURE: after optimizing, find single-instruction loops, replace with use of ILC
291 // FEATURE: consider doing loop unrolling if two copies of the loop fit in the instruction buffer...
292 // FEATURE: clever instruction re-oredering?
296 * The code emitted by this method makes the following assumptions:
298 * - The instructions emitted are dispatched in order
299 * - At the time of dispatch, the dock must be pre-quiescent.
302 public void emit(ArrayList<Instruction> ic) {
306 // FIXME: if this loop is a count==1 loop, we can emit the successor loop along with it...
308 // the number of instructions after and including the first blocking instruction
309 int numInstructionsNotIncludingNonblockingPrefix = 0;
311 boolean blockingInstructionEncountered = false;
313 // Set the OLC (it might previously have been zero)
314 ic.add(new Set(dock, false, Predicate.IgnoreFlagD, SetDest.OuterLoopCounter, count==0 ? 1 : count));
316 ic.add(new Instruction.Head(dock));
319 for(Instruction i : instructions) {
320 if (i instanceof Move && (((Move)i).tokenIn || ((Move)i).dataIn))
321 blockingInstructionEncountered = true;
322 if (blockingInstructionEncountered)
323 numInstructionsNotIncludingNonblockingPrefix++;
329 if (!instructionFifoSizeCheckDisabled &&
330 numInstructionsNotIncludingNonblockingPrefix > dock.getInstructionFifoSize())
331 throw new RuntimeException("instruction sequence is too long for instruction fifo at " + dock);
334 ic.add(new Instruction.Set(dock, true, Predicate.Default, SetDest.OuterLoopCounter, SetSource.Decrement));
335 if (blockingInstructionEncountered)
336 numInstructionsNotIncludingNonblockingPrefix++;
341 ic.add(new Instruction.Abort(dock, Predicate.FlagD));
343 if (ctx.autoflush && !"Debug".equals(dock.getShip().getType()) && next==null) {
344 if (dock.isInputDock())
345 ic.add(new Instruction.Flush(dock, true, Predicate.FlagD));
348 // FIXME: need to somehow deal with count!=0 loops that are
349 // torpedoable; they need to wait for a torpedo to arrive
350 // after exhausting their count.
353 ic.add(new Instruction.Tail(dock));
354 if (!instructionFifoSizeCheckDisabled &&
355 loopSize > dock.getInstructionFifoSize())
356 throw new RuntimeException("instruction loop is too long for instruction fifo");
360 if (count != 1) throw new RuntimeException("no support for successor loops when count!=1 yet");
361 // FIXME: must include check based on reduced FIFO capacity
362 // FIXME: review this
367 void warn(String warning) {
368 System.err.println("warning: " + warning);
371 // Helpers //////////////////////////////////////////////////////////////////////////////
373 public void recvWord() { recv(true, false); }
374 public void recvPath() { recv(false, true); }
375 public void recvPacket() { recv(true, true); }
376 public void collectWord() { collect(true, false); }
377 public void collectPath() { collect(false, true); }
378 public void collectPacket() { collect(true, true); }