31  * Opcodes are accumulated with specific methods. A control-flow stack
60 		cfPtr = -1;  in WordBuilder()
69 	 * Build the word. The control-flow stack must be empty. A 'ret'
74 		if (cfPtr != -1) {  in Build()
75 			throw new Exception("control-flow stack is not empty");  in Build()
77 		if (jumpToLast || code[code.Count - 1].MayFallThrough) {  in Build()
86 	void Add(Opcode op)  in Add()  method in WordBuilder
88 		Add(op, null);  in Add()
91 	void Add(Opcode op, string refName)  in Add()  method in WordBuilder
93 		code.Add(op);  in Add()
94 		toResolve.Add(refName);  in Add()
99 	 * Rotate the control-flow stack at depth 'depth'.
103 		int x = cfStack[cfPtr - depth];  in CSRoll()
104 		Array.Copy(cfStack, cfPtr - (depth - 1),  in CSRoll()
105 			cfStack, cfPtr - depth, depth);  in CSRoll()
110 	 * Make a copy of the control-flow element at depth 'depth', and
111 	 * push it on top of the control-flow stack.
115 		int x = cfStack[cfPtr - depth];  in CSPick()
132 		return cfStack[cfPtr --];  in CSPop()
136 	 * Push an origin on the control-flow stack, corresponding to the
137 	 * next opcode to add.
145 	 * Push a destination on the control-flow stack, corresponding to
146 	 * the next opcode to add.
150 		CSPush(-code.Count - 1);  in CSPushDest()
154 	 * Pop an origin from the control-flow stack. An exception is
167 	 * Pop a destination from the control-flow stack. An exception is
176 		return -x - 1;  in CSPopDest()
180 	 * Add a "push literal" opcode.
184 		Add(new OpcodeConst(v));  in Literal()
191 	 *  - If the target is '>' followed by a local variable name, then
194 	 *  - Otherwise, if the target is a local variable name, then a
197 	 *  - Otherwise, a call to the named word is added. The target name
198 	 *    will be resolved later on (typically, when the word containing
215 				Add(new OpcodePutLocal(lnum));  in Call()
217 				Add(new OpcodeGetLocal(lnum));  in Call()
220 			Add(new OpcodeCall(), target);  in Call()
225 	 * Add a "call" opcode to the designated word.
229 		Add(new OpcodeCall(wtarget), null);  in CallExt()
233 	 * Add a "call" opcode to a word which is not currently resolved.
238 		Add(new OpcodeCall(), target);  in CallExt()
242 	 * Add a "get local" opcode; the provided local name must already
249 			Add(new OpcodeGetLocal(lnum));  in GetLocal()
256 	 * Add a "put local" opcode; the provided local name must already
263 			Add(new OpcodePutLocal(lnum));  in PutLocal()
282 	 * Add a "call" opcode whose target is an XT value (which may be
288 			Add(new OpcodeCall(), xt.Name);  in Call()
290 			Add(new OpcodeCall(xt.Target));  in Call()
295 	 * Add a "ret" opcode.
299 		Add(new OpcodeRet());  in Ret()
303 	 * Add a forward unconditional jump. The new opcode address is
304 	 * pushed on the control-flow stack as an origin.
309 		Add(new OpcodeJumpUncond());  in Ahead()
313 	 * Add a forward conditional jump, which will be taken at runtime
314 	 * if the top-of-stack value is 'true'. The new opcode address is
315 	 * pushed on the control-flow stack as an origin.
320 		Add(new OpcodeJumpIf());  in AheadIf()
324 	 * Add a forward conditional jump, which will be taken at runtime
325 	 * if the top-of-stack value is 'false'. The new opcode address is
326 	 * pushed on the control-flow stack as an origin.
331 		Add(new OpcodeJumpIfNot());  in AheadIfNot()
336 	 * The top of control-flow stack is popped and must be an origin.
341 		code[x].ResolveJump(code.Count - x - 1);  in Then()
346 	 * Push the current code address on the control-flow stack as a
355 	 * Add a backward unconditional jump. The jump target is popped
356 	 * from the control-flow stack as a destination.
361 		Add(new OpcodeJumpUncond(x - code.Count - 1));  in Again()
365 	 * Add a backward conditional jump, which will be taken at runtime
366 	 * if the top-of-stack value is 'true'. The jump target is popped
367 	 * from the control-flow stack as a destination.
372 		Add(new OpcodeJumpIf(x - code.Count - 1));  in AgainIf()
376 	 * Add a backward conditional jump, which will be taken at runtime
377 	 * if the top-of-stack value is 'false'. The jump target is popped
378 	 * from the control-flow stack as a destination.
383 		Add(new OpcodeJumpIfNot(x - code.Count - 1));  in AgainIfNot()