1 /* ----------------------------------------------------------------------------
3 * (c) The GHC Team, 1998-2004
5 * Entry code for various built-in closure types.
7 * This file is written in a subset of C--, extended with various
8 * features specific to GHC. It is compiled by GHC directly. For the
9 * syntax of .cmm files, see the parser in ghc/compiler/cmm/CmmParse.y.
11 * --------------------------------------------------------------------------*/
15 /* ----------------------------------------------------------------------------
16 Support for the bytecode interpreter.
17 ------------------------------------------------------------------------- */
19 /* 9 bits of return code for constructors created by the interpreter. */
20 stg_interp_constr_entry
22 /* R1 points at the constructor */
23 jump %ENTRY_CODE(Sp(0));
26 /* Some info tables to be used when compiled code returns a value to
27 the interpreter, i.e. the interpreter pushes one of these onto the
28 stack before entering a value. What the code does is to
29 impedance-match the compiled return convention (in R1p/R1n/F1/D1 etc) to
30 the interpreter's convention (returned value is on top of stack),
31 and then cause the scheduler to enter the interpreter.
33 On entry, the stack (growing down) looks like this:
35 ptr to BCO holding return continuation
36 ptr to one of these info tables.
38 The info table code, both direct and vectored, must:
39 * push R1/F1/D1 on the stack, and its tag if necessary
40 * push the BCO (so it's now on the stack twice)
41 * Yield, ie, go to the scheduler.
43 Scheduler examines the t.o.s, discovers it is a BCO, and proceeds
44 directly to the bytecode interpreter. That pops the top element
45 (the BCO, containing the return continuation), and interprets it.
46 Net result: return continuation gets interpreted, with the
50 ptr to the info table just jumped thru
53 which is just what we want -- the "standard" return layout for the
56 Don't ask me how unboxed tuple returns are supposed to work. We
57 haven't got a good story about that yet.
60 INFO_TABLE_RET( stg_ctoi_R1p, RET_BCO)
64 Sp(0) = stg_enter_info;
65 jump stg_yield_to_interpreter;
69 * When the returned value is a pointer, but unlifted, in R1 ...
71 INFO_TABLE_RET( stg_ctoi_R1unpt, RET_BCO )
75 Sp(0) = stg_gc_unpt_r1_info;
76 jump stg_yield_to_interpreter;
80 * When the returned value is a non-pointer in R1 ...
82 INFO_TABLE_RET( stg_ctoi_R1n, RET_BCO )
86 Sp(0) = stg_gc_unbx_r1_info;
87 jump stg_yield_to_interpreter;
91 * When the returned value is in F1
93 INFO_TABLE_RET( stg_ctoi_F1, RET_BCO )
97 Sp(0) = stg_gc_f1_info;
98 jump stg_yield_to_interpreter;
102 * When the returned value is in D1
104 INFO_TABLE_RET( stg_ctoi_D1, RET_BCO )
106 Sp_adj(-1) - SIZEOF_DOUBLE;
107 D_[Sp + WDS(1)] = D1;
108 Sp(0) = stg_gc_d1_info;
109 jump stg_yield_to_interpreter;
113 * When the returned value is in L1
115 INFO_TABLE_RET( stg_ctoi_L1, RET_BCO )
118 L_[Sp + WDS(1)] = L1;
119 Sp(0) = stg_gc_l1_info;
120 jump stg_yield_to_interpreter;
124 * When the returned value is a void
126 INFO_TABLE_RET( stg_ctoi_V, RET_BCO )
129 Sp(0) = stg_gc_void_info;
130 jump stg_yield_to_interpreter;
134 * Dummy info table pushed on the top of the stack when the interpreter
135 * should apply the BCO on the stack to its arguments, also on the
138 INFO_TABLE_RET( stg_apply_interp, RET_BCO )
140 /* Just in case we end up in here... (we shouldn't) */
141 jump stg_yield_to_interpreter;
144 /* ----------------------------------------------------------------------------
146 ------------------------------------------------------------------------- */
148 INFO_TABLE_FUN( stg_BCO, 4, 0, BCO, "BCO", "BCO", ARG_BCO )
150 /* entering a BCO means "apply it", same as a function */
153 Sp(0) = stg_apply_interp_info;
154 jump stg_yield_to_interpreter;
157 /* ----------------------------------------------------------------------------
158 Info tables for indirections.
160 SPECIALISED INDIRECTIONS: we have a specialised indirection for direct returns,
161 so that we can avoid entering
162 the object when we know it points directly to a value. The update
163 code (Updates.cmm) updates objects with the appropriate kind of
164 indirection. We only do this for young-gen indirections.
165 ------------------------------------------------------------------------- */
167 INFO_TABLE(stg_IND,1,0,IND,"IND","IND")
169 TICK_ENT_DYN_IND(); /* tick */
170 R1 = StgInd_indirectee(R1);
175 INFO_TABLE(stg_IND_direct,1,0,IND,"IND","IND")
177 TICK_ENT_DYN_IND(); /* tick */
178 R1 = StgInd_indirectee(R1);
180 jump %ENTRY_CODE(Sp(0));
183 INFO_TABLE(stg_IND_STATIC,1,0,IND_STATIC,"IND_STATIC","IND_STATIC")
185 TICK_ENT_STATIC_IND(); /* tick */
186 R1 = StgInd_indirectee(R1);
191 INFO_TABLE(stg_IND_PERM,1,0,IND_PERM,"IND_PERM","IND_PERM")
193 /* Don't add INDs to granularity cost */
195 /* Don't: TICK_ENT_STATIC_IND(Node); for ticky-ticky; this ind is
196 here only to help profiling */
198 #if defined(TICKY_TICKY) && !defined(PROFILING)
199 /* TICKY_TICKY && !PROFILING means PERM_IND *replaces* an IND, rather than
206 /* Enter PAP cost centre */
207 ENTER_CCS_PAP_CL(R1);
209 /* For ticky-ticky, change the perm_ind to a normal ind on first
210 * entry, so the number of ent_perm_inds is the number of *thunks*
211 * entered again, not the number of subsequent entries.
213 * Since this screws up cost centres, we die if profiling and
214 * ticky_ticky are on at the same time. KSW 1999-01.
218 # error Profiling and ticky-ticky do not mix at present!
219 # endif /* PROFILING */
220 StgHeader_info(R1) = stg_IND_info;
221 #endif /* TICKY_TICKY */
223 R1 = StgInd_indirectee(R1);
225 #if defined(TICKY_TICKY) && !defined(PROFILING)
233 INFO_TABLE(stg_IND_OLDGEN,1,0,IND_OLDGEN,"IND_OLDGEN","IND_OLDGEN")
235 TICK_ENT_STATIC_IND(); /* tick */
236 R1 = StgInd_indirectee(R1);
241 INFO_TABLE(stg_IND_OLDGEN_PERM,1,0,IND_OLDGEN_PERM,"IND_OLDGEN_PERM","IND_OLDGEN_PERM")
243 /* Don't: TICK_ENT_STATIC_IND(Node); for ticky-ticky;
244 this ind is here only to help profiling */
246 #if defined(TICKY_TICKY) && !defined(PROFILING)
247 /* TICKY_TICKY && !PROFILING means PERM_IND *replaces* an IND,
248 rather than being extra */
249 TICK_ENT_PERM_IND(); /* tick */
254 /* Enter PAP cost centre -- lexical scoping only */
255 ENTER_CCS_PAP_CL(R1);
257 /* see comment in IND_PERM */
260 # error Profiling and ticky-ticky do not mix at present!
261 # endif /* PROFILING */
262 StgHeader_info(R1) = stg_IND_OLDGEN_info;
263 #endif /* TICKY_TICKY */
265 R1 = StgInd_indirectee(R1);
271 /* ----------------------------------------------------------------------------
274 Entering a black hole normally causes a cyclic data dependency, but
275 in the concurrent world, black holes are synchronization points,
276 and they are turned into blocking queues when there are threads
277 waiting for the evaluation of the closure to finish.
278 ------------------------------------------------------------------------- */
280 /* Note: a BLACKHOLE must be big enough to be
281 * overwritten with an indirection/evacuee/catch. Thus we claim it
282 * has 1 non-pointer word of payload.
284 INFO_TABLE(stg_BLACKHOLE,0,1,BLACKHOLE,"BLACKHOLE","BLACKHOLE")
287 /* Before overwriting TSO_LINK */
288 STGCALL3(GranSimBlock,CurrentTSO,CurrentProc,(StgClosure *)R1 /*Node*/);
294 // foreign "C" debugBelch("BLACKHOLE entry\n");
297 /* Actually this is not necessary because R1 is about to be destroyed. */
300 #if defined(THREADED_RTS)
301 foreign "C" ACQUIRE_LOCK(sched_mutex "ptr");
302 // released in stg_block_blackhole_finally
305 /* Put ourselves on the blackhole queue */
306 StgTSO_link(CurrentTSO) = W_[blackhole_queue];
307 W_[blackhole_queue] = CurrentTSO;
309 /* jot down why and on what closure we are blocked */
310 StgTSO_why_blocked(CurrentTSO) = BlockedOnBlackHole::I16;
311 StgTSO_block_info(CurrentTSO) = R1;
313 jump stg_block_blackhole;
316 #if defined(PAR) || defined(GRAN)
318 INFO_TABLE(stg_RBH,1,1,RBH,"RBH","RBH")
321 /* mainly statistics gathering for GranSim simulation */
322 STGCALL3(GranSimBlock,CurrentTSO,CurrentProc,(StgClosure *)R1 /*Node*/);
325 /* exactly the same as a BLACKHOLE_BQ_entry -- HWL */
326 /* Put ourselves on the blocking queue for this black hole */
327 TSO_link(CurrentTSO) = StgBlockingQueue_blocking_queue(R1);
328 StgBlockingQueue_blocking_queue(R1) = CurrentTSO;
329 /* jot down why and on what closure we are blocked */
330 TSO_why_blocked(CurrentTSO) = BlockedOnBlackHole::I16;
331 TSO_block_info(CurrentTSO) = R1;
333 /* PAR: dumping of event now done in blockThread -- HWL */
335 /* stg_gen_block is too heavyweight, use a specialised one */
339 INFO_TABLE(stg_RBH_Save_0,0,2,CONSTR,"RBH_Save_0","RBH_Save_0")
340 { foreign "C" barf("RBH_Save_0 object entered!"); }
342 INFO_TABLE(stg_RBH_Save_1,1,1,CONSTR,"RBH_Save_1","RBH_Save_1");
343 { foreign "C" barf("RBH_Save_1 object entered!"); }
345 INFO_TABLE(stg_RBH_Save_2,2,0,CONSTR,"RBH_Save_2","RBH_Save_2");
346 { foreign "C" barf("RBH_Save_2 object entered!"); }
348 #endif /* defined(PAR) || defined(GRAN) */
350 /* identical to BLACKHOLEs except for the infotag */
351 INFO_TABLE(stg_CAF_BLACKHOLE,0,1,CAF_BLACKHOLE,"CAF_BLACKHOLE","CAF_BLACKHOLE")
354 /* mainly statistics gathering for GranSim simulation */
355 STGCALL3(GranSimBlock,CurrentTSO,CurrentProc,(StgClosure *)R1 /*Node*/);
361 #if defined(THREADED_RTS)
362 // foreign "C" debugBelch("BLACKHOLE entry\n");
365 #if defined(THREADED_RTS)
366 foreign "C" ACQUIRE_LOCK(sched_mutex "ptr");
367 // released in stg_block_blackhole_finally
370 /* Put ourselves on the blackhole queue */
371 StgTSO_link(CurrentTSO) = W_[blackhole_queue];
372 W_[blackhole_queue] = CurrentTSO;
374 /* jot down why and on what closure we are blocked */
375 StgTSO_why_blocked(CurrentTSO) = BlockedOnBlackHole::I16;
376 StgTSO_block_info(CurrentTSO) = R1;
378 jump stg_block_blackhole;
381 #ifdef EAGER_BLACKHOLING
382 INFO_TABLE(stg_SE_BLACKHOLE,0,1,SE_BLACKHOLE,"SE_BLACKHOLE","SE_BLACKHOLE")
383 { foreign "C" barf("SE_BLACKHOLE object entered!"); }
385 INFO_TABLE(stg_SE_CAF_BLACKHOLE,0,1,SE_CAF_BLACKHOLE,"SE_CAF_BLACKHOLE","SE_CAF_BLACKHOLE")
386 { foreign "C" barf("SE_CAF_BLACKHOLE object entered!"); }
389 /* ----------------------------------------------------------------------------
390 Whiteholes are used for the "locked" state of a closure (see lockClosure())
392 The closure type is BLAKCHOLE, just because we need a valid closure type
394 ------------------------------------------------------------------------- */
396 INFO_TABLE(stg_WHITEHOLE, 0,0, BLACKHOLE, "WHITEHOLE", "WHITEHOLE")
397 { foreign "C" barf("WHITEHOLE object entered!"); }
399 /* ----------------------------------------------------------------------------
400 Some static info tables for things that don't get entered, and
401 therefore don't need entry code (i.e. boxed but unpointed objects)
402 NON_ENTERABLE_ENTRY_CODE now defined at the beginning of the file
403 ------------------------------------------------------------------------- */
405 INFO_TABLE(stg_TSO, 0,0,TSO, "TSO", "TSO")
406 { foreign "C" barf("TSO object entered!"); }
408 /* ----------------------------------------------------------------------------
409 Evacuees are left behind by the garbage collector. Any attempt to enter
411 ------------------------------------------------------------------------- */
413 INFO_TABLE(stg_EVACUATED,1,0,EVACUATED,"EVACUATED","EVACUATED")
414 { foreign "C" barf("EVACUATED object entered!"); }
416 /* ----------------------------------------------------------------------------
419 Live weak pointers have a special closure type. Dead ones are just
420 nullary constructors (although they live on the heap - we overwrite
421 live weak pointers with dead ones).
422 ------------------------------------------------------------------------- */
424 INFO_TABLE(stg_WEAK,0,4,WEAK,"WEAK","WEAK")
425 { foreign "C" barf("WEAK object entered!"); }
428 * It's important when turning an existing WEAK into a DEAD_WEAK
429 * (which is what finalizeWeak# does) that we don't lose the link
430 * field and break the linked list of weak pointers. Hence, we give
431 * DEAD_WEAK 4 non-pointer fields, the same as WEAK.
433 INFO_TABLE_CONSTR(stg_DEAD_WEAK,0,4,0,CONSTR,"DEAD_WEAK","DEAD_WEAK")
434 { foreign "C" barf("DEAD_WEAK object entered!"); }
436 /* ----------------------------------------------------------------------------
439 This is a static nullary constructor (like []) that we use to mark an empty
440 finalizer in a weak pointer object.
441 ------------------------------------------------------------------------- */
443 INFO_TABLE_CONSTR(stg_NO_FINALIZER,0,0,0,CONSTR_NOCAF_STATIC,"NO_FINALIZER","NO_FINALIZER")
444 { foreign "C" barf("NO_FINALIZER object entered!"); }
446 CLOSURE(stg_NO_FINALIZER_closure,stg_NO_FINALIZER);
448 /* ----------------------------------------------------------------------------
449 Stable Names are unlifted too.
450 ------------------------------------------------------------------------- */
452 INFO_TABLE(stg_STABLE_NAME,0,1,STABLE_NAME,"STABLE_NAME","STABLE_NAME")
453 { foreign "C" barf("STABLE_NAME object entered!"); }
455 /* ----------------------------------------------------------------------------
458 There are two kinds of these: full and empty. We need an info table
459 and entry code for each type.
460 ------------------------------------------------------------------------- */
462 INFO_TABLE(stg_FULL_MVAR,3,0,MVAR,"MVAR","MVAR")
463 { foreign "C" barf("FULL_MVAR object entered!"); }
465 INFO_TABLE(stg_EMPTY_MVAR,3,0,MVAR,"MVAR","MVAR")
466 { foreign "C" barf("EMPTY_MVAR object entered!"); }
468 /* -----------------------------------------------------------------------------
470 -------------------------------------------------------------------------- */
472 INFO_TABLE(stg_TVAR, 0, 0, TVAR, "TVAR", "TVAR")
473 { foreign "C" barf("TVAR object entered!"); }
475 INFO_TABLE(stg_TVAR_WATCH_QUEUE, 0, 0, TVAR_WATCH_QUEUE, "TVAR_WATCH_QUEUE", "TVAR_WATCH_QUEUE")
476 { foreign "C" barf("TVAR_WATCH_QUEUE object entered!"); }
478 INFO_TABLE(stg_ATOMIC_INVARIANT, 0, 0, ATOMIC_INVARIANT, "ATOMIC_INVARIANT", "ATOMIC_INVARIANT")
479 { foreign "C" barf("ATOMIC_INVARIANT object entered!"); }
481 INFO_TABLE(stg_INVARIANT_CHECK_QUEUE, 0, 0, INVARIANT_CHECK_QUEUE, "INVARIANT_CHECK_QUEUE", "INVARIANT_CHECK_QUEUE")
482 { foreign "C" barf("INVARIANT_CHECK_QUEUE object entered!"); }
484 INFO_TABLE(stg_TREC_CHUNK, 0, 0, TREC_CHUNK, "TREC_CHUNK", "TREC_CHUNK")
485 { foreign "C" barf("TREC_CHUNK object entered!"); }
487 INFO_TABLE(stg_TREC_HEADER, 0, 0, TREC_HEADER, "TREC_HEADER", "TREC_HEADER")
488 { foreign "C" barf("TREC_HEADER object entered!"); }
490 INFO_TABLE_CONSTR(stg_END_STM_WATCH_QUEUE,0,0,0,CONSTR_NOCAF_STATIC,"END_STM_WATCH_QUEUE","END_STM_WATCH_QUEUE")
491 { foreign "C" barf("END_STM_WATCH_QUEUE object entered!"); }
493 INFO_TABLE_CONSTR(stg_END_INVARIANT_CHECK_QUEUE,0,0,0,CONSTR_NOCAF_STATIC,"END_INVARIANT_CHECK_QUEUE","END_INVARIANT_CHECK_QUEUE")
494 { foreign "C" barf("END_INVARIANT_CHECK_QUEUE object entered!"); }
496 INFO_TABLE_CONSTR(stg_END_STM_CHUNK_LIST,0,0,0,CONSTR_NOCAF_STATIC,"END_STM_CHUNK_LIST","END_STM_CHUNK_LIST")
497 { foreign "C" barf("END_STM_CHUNK_LIST object entered!"); }
499 INFO_TABLE_CONSTR(stg_NO_TREC,0,0,0,CONSTR_NOCAF_STATIC,"NO_TREC","NO_TREC")
500 { foreign "C" barf("NO_TREC object entered!"); }
502 CLOSURE(stg_END_STM_WATCH_QUEUE_closure,stg_END_STM_WATCH_QUEUE);
504 CLOSURE(stg_END_INVARIANT_CHECK_QUEUE_closure,stg_END_INVARIANT_CHECK_QUEUE);
506 CLOSURE(stg_END_STM_CHUNK_LIST_closure,stg_END_STM_CHUNK_LIST);
508 CLOSURE(stg_NO_TREC_closure,stg_NO_TREC);
510 /* ----------------------------------------------------------------------------
513 This is a static nullary constructor (like []) that we use to mark the
514 end of a linked TSO queue.
515 ------------------------------------------------------------------------- */
517 INFO_TABLE_CONSTR(stg_END_TSO_QUEUE,0,0,0,CONSTR_NOCAF_STATIC,"END_TSO_QUEUE","END_TSO_QUEUE")
518 { foreign "C" barf("END_TSO_QUEUE object entered!"); }
520 CLOSURE(stg_END_TSO_QUEUE_closure,stg_END_TSO_QUEUE);
522 /* ----------------------------------------------------------------------------
524 ------------------------------------------------------------------------- */
526 INFO_TABLE_CONSTR(stg_END_EXCEPTION_LIST,0,0,0,CONSTR_NOCAF_STATIC,"END_EXCEPTION_LIST","END_EXCEPTION_LIST")
527 { foreign "C" barf("END_EXCEPTION_LIST object entered!"); }
529 CLOSURE(stg_END_EXCEPTION_LIST_closure,stg_END_EXCEPTION_LIST);
531 INFO_TABLE(stg_EXCEPTION_CONS,1,1,CONSTR,"EXCEPTION_CONS","EXCEPTION_CONS")
532 { foreign "C" barf("EXCEPTION_CONS object entered!"); }
534 /* ----------------------------------------------------------------------------
537 These come in two basic flavours: arrays of data (StgArrWords) and arrays of
538 pointers (StgArrPtrs). They all have a similar layout:
540 ___________________________
541 | Info | No. of | data....
543 ---------------------------
545 These are *unpointed* objects: i.e. they cannot be entered.
547 ------------------------------------------------------------------------- */
549 INFO_TABLE(stg_ARR_WORDS, 0, 0, ARR_WORDS, "ARR_WORDS", "ARR_WORDS")
550 { foreign "C" barf("ARR_WORDS object entered!"); }
552 INFO_TABLE(stg_MUT_ARR_PTRS_CLEAN, 0, 0, MUT_ARR_PTRS_CLEAN, "MUT_ARR_PTRS_CLEAN", "MUT_ARR_PTRS_CLEAN")
553 { foreign "C" barf("MUT_ARR_PTRS_CLEAN object entered!"); }
555 INFO_TABLE(stg_MUT_ARR_PTRS_DIRTY, 0, 0, MUT_ARR_PTRS_DIRTY, "MUT_ARR_PTRS_DIRTY", "MUT_ARR_PTRS_DIRTY")
556 { foreign "C" barf("MUT_ARR_PTRS_DIRTY object entered!"); }
558 INFO_TABLE(stg_MUT_ARR_PTRS_FROZEN, 0, 0, MUT_ARR_PTRS_FROZEN, "MUT_ARR_PTRS_FROZEN", "MUT_ARR_PTRS_FROZEN")
559 { foreign "C" barf("MUT_ARR_PTRS_FROZEN object entered!"); }
561 INFO_TABLE(stg_MUT_ARR_PTRS_FROZEN0, 0, 0, MUT_ARR_PTRS_FROZEN0, "MUT_ARR_PTRS_FROZEN0", "MUT_ARR_PTRS_FROZEN0")
562 { foreign "C" barf("MUT_ARR_PTRS_FROZEN0 object entered!"); }
564 /* ----------------------------------------------------------------------------
566 ------------------------------------------------------------------------- */
568 INFO_TABLE(stg_MUT_VAR_CLEAN, 1, 0, MUT_VAR_CLEAN, "MUT_VAR_CLEAN", "MUT_VAR_CLEAN")
569 { foreign "C" barf("MUT_VAR_CLEAN object entered!"); }
570 INFO_TABLE(stg_MUT_VAR_DIRTY, 1, 0, MUT_VAR_DIRTY, "MUT_VAR_DIRTY", "MUT_VAR_DIRTY")
571 { foreign "C" barf("MUT_VAR_DIRTY object entered!"); }
573 /* ----------------------------------------------------------------------------
576 Entering this closure will just return to the address on the top of the
577 stack. Useful for getting a thread in a canonical form where we can
578 just enter the top stack word to start the thread. (see deleteThread)
579 * ------------------------------------------------------------------------- */
581 INFO_TABLE( stg_dummy_ret, 0, 0, CONSTR_NOCAF_STATIC, "DUMMY_RET", "DUMMY_RET")
583 jump %ENTRY_CODE(Sp(0));
585 CLOSURE(stg_dummy_ret_closure,stg_dummy_ret);
587 /* ----------------------------------------------------------------------------
588 CHARLIKE and INTLIKE closures.
590 These are static representations of Chars and small Ints, so that
591 we can remove dynamic Chars and Ints during garbage collection and
592 replace them with references to the static objects.
593 ------------------------------------------------------------------------- */
595 #if defined(ENABLE_WIN32_DLL_SUPPORT)
597 * When sticking the RTS in a DLL, we delay populating the
598 * Charlike and Intlike tables until load-time, which is only
599 * when we've got the real addresses to the C# and I# closures.
602 static INFO_TBL_CONST StgInfoTable czh_static_info;
603 static INFO_TBL_CONST StgInfoTable izh_static_info;
604 #define Char_hash_static_info czh_static_info
605 #define Int_hash_static_info izh_static_info
607 #define Char_hash_static_info base_GHCziBase_Czh_static
608 #define Int_hash_static_info base_GHCziBase_Izh_static
612 #define CHARLIKE_HDR(n) CLOSURE(Char_hash_static_info, n)
613 #define INTLIKE_HDR(n) CLOSURE(Int_hash_static_info, n)
615 /* put these in the *data* section, since the garbage collector relies
616 * on the fact that static closures live in the data section.
619 /* end the name with _closure, to convince the mangler this is a closure */
622 stg_CHARLIKE_closure:
883 INTLIKE_HDR(-16) /* MIN_INTLIKE == -16 */
915 INTLIKE_HDR(16) /* MAX_INTLIKE == 16 */