src/bytecode.c

   1 /* Execution of byte code produced by bytecomp.el.
   2    Copyright (C) 1985, 1986, 1987, 1988, 1993, 2000 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Emacs.
   5
   6 GNU Emacs is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Emacs is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Emacs; see the file COPYING.  If not, write to
  18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.
  20
  21 hacked on by jwz@lucid.com 17-jun-91
  22   o  added a compile-time switch to turn on simple sanity checking;
  23   o  put back the obsolete byte-codes for error-detection;
  24   o  added a new instruction, unbind_all, which I will use for
  25      tail-recursion elimination;
  26   o  made temp_output_buffer_show be called with the right number
  27      of args;
  28   o  made the new bytecodes be called with args in the right order;
  29   o  added metering support.
  30
  31 by Hallvard:
  32   o  added relative jump instructions;
  33   o  all conditionals now only do QUIT if they jump.
  34  */
  35
  36 #include <config.h>
  37 #include "lisp.h"
  38 #include "buffer.h"
  39 #include "charset.h"
  40 #include "syntax.h"
  41
  42 #ifdef CHECK_FRAME_FONT
  43 #include "frame.h"
  44 #include "xterm.h"
  45 #endif
  46
  47 /*
  48  * define BYTE_CODE_SAFE to enable some minor sanity checking (useful for
  49  * debugging the byte compiler...)
  50  *
  51  * define BYTE_CODE_METER to enable generation of a byte-op usage histogram.
  52  */
  53 /* #define BYTE_CODE_SAFE */
  54 /* #define BYTE_CODE_METER */
  55
  56 \f
  57 #ifdef BYTE_CODE_METER
  58
  59 Lisp_Object Vbyte_code_meter, Qbyte_code_meter;
  60 int byte_metering_on;
  61
  62 #define METER_2(code1, code2) \
  63   XFASTINT (XVECTOR (XVECTOR (Vbyte_code_meter)->contents[(code1)]) \
  64             ->contents[(code2)])
  65
  66 #define METER_1(code) METER_2 (0, (code))
  67
  68 #define METER_CODE(last_code, this_code)                        \
  69 {                                                               \
  70   if (byte_metering_on)                                         \
  71     {                                                           \
  72       if (METER_1 (this_code) != ((1<<VALBITS)-1))              \
  73         METER_1 (this_code)++;                                  \
  74       if (last_code                                             \
  75           && METER_2 (last_code, this_code) != ((1<<VALBITS)-1))\
  76         METER_2 (last_code, this_code)++;                       \
  77     }                                                           \
  78 }
  79
  80 #else /* no BYTE_CODE_METER */
  81
  82 #define METER_CODE(last_code, this_code)
  83
  84 #endif /* no BYTE_CODE_METER */
  85 \f
  86
  87 Lisp_Object Qbytecode;
  88
  89 /*  Byte codes: */
  90
  91 #define Bvarref 010
  92 #define Bvarset 020
  93 #define Bvarbind 030
  94 #define Bcall 040
  95 #define Bunbind 050
  96
  97 #define Bnth 070
  98 #define Bsymbolp 071
  99 #define Bconsp 072
 100 #define Bstringp 073
 101 #define Blistp 074
 102 #define Beq 075
 103 #define Bmemq 076
 104 #define Bnot 077
 105 #define Bcar 0100
 106 #define Bcdr 0101
 107 #define Bcons 0102
 108 #define Blist1 0103
 109 #define Blist2 0104
 110 #define Blist3 0105
 111 #define Blist4 0106
 112 #define Blength 0107
 113 #define Baref 0110
 114 #define Baset 0111
 115 #define Bsymbol_value 0112
 116 #define Bsymbol_function 0113
 117 #define Bset 0114
 118 #define Bfset 0115
 119 #define Bget 0116
 120 #define Bsubstring 0117
 121 #define Bconcat2 0120
 122 #define Bconcat3 0121
 123 #define Bconcat4 0122
 124 #define Bsub1 0123
 125 #define Badd1 0124
 126 #define Beqlsign 0125
 127 #define Bgtr 0126
 128 #define Blss 0127
 129 #define Bleq 0130
 130 #define Bgeq 0131
 131 #define Bdiff 0132
 132 #define Bnegate 0133
 133 #define Bplus 0134
 134 #define Bmax 0135
 135 #define Bmin 0136
 136 #define Bmult 0137
 137
 138 #define Bpoint 0140
 139 /* Was Bmark in v17.  */
 140 #define Bsave_current_buffer 0141
 141 #define Bgoto_char 0142
 142 #define Binsert 0143
 143 #define Bpoint_max 0144
 144 #define Bpoint_min 0145
 145 #define Bchar_after 0146
 146 #define Bfollowing_char 0147
 147 #define Bpreceding_char 0150
 148 #define Bcurrent_column 0151
 149 #define Bindent_to 0152
 150 #define Bscan_buffer 0153 /* No longer generated as of v18 */
 151 #define Beolp 0154
 152 #define Beobp 0155
 153 #define Bbolp 0156
 154 #define Bbobp 0157
 155 #define Bcurrent_buffer 0160
 156 #define Bset_buffer 0161
 157 #define Bsave_current_buffer_1 0162 /* Replacing Bsave_current_buffer.  */
 158 #define Bread_char 0162 /* No longer generated as of v19 */
 159 #define Bset_mark 0163 /* this loser is no longer generated as of v18 */
 160 #define Binteractive_p 0164 /* Needed since interactive-p takes unevalled args */
 161
 162 #define Bforward_char 0165
 163 #define Bforward_word 0166
 164 #define Bskip_chars_forward 0167
 165 #define Bskip_chars_backward 0170
 166 #define Bforward_line 0171
 167 #define Bchar_syntax 0172
 168 #define Bbuffer_substring 0173
 169 #define Bdelete_region 0174
 170 #define Bnarrow_to_region 0175
 171 #define Bwiden 0176
 172 #define Bend_of_line 0177
 173
 174 #define Bconstant2 0201
 175 #define Bgoto 0202
 176 #define Bgotoifnil 0203
 177 #define Bgotoifnonnil 0204
 178 #define Bgotoifnilelsepop 0205
 179 #define Bgotoifnonnilelsepop 0206
 180 #define Breturn 0207
 181 #define Bdiscard 0210
 182 #define Bdup 0211
 183
 184 #define Bsave_excursion 0212
 185 #define Bsave_window_excursion 0213
 186 #define Bsave_restriction 0214
 187 #define Bcatch 0215
 188
 189 #define Bunwind_protect 0216
 190 #define Bcondition_case 0217
 191 #define Btemp_output_buffer_setup 0220
 192 #define Btemp_output_buffer_show 0221
 193
 194 #define Bunbind_all 0222
 195
 196 #define Bset_marker 0223
 197 #define Bmatch_beginning 0224
 198 #define Bmatch_end 0225
 199 #define Bupcase 0226
 200 #define Bdowncase 0227
 201
 202 #define Bstringeqlsign 0230
 203 #define Bstringlss 0231
 204 #define Bequal 0232
 205 #define Bnthcdr 0233
 206 #define Belt 0234
 207 #define Bmember 0235
 208 #define Bassq 0236
 209 #define Bnreverse 0237
 210 #define Bsetcar 0240
 211 #define Bsetcdr 0241
 212 #define Bcar_safe 0242
 213 #define Bcdr_safe 0243
 214 #define Bnconc 0244
 215 #define Bquo 0245
 216 #define Brem 0246
 217 #define Bnumberp 0247
 218 #define Bintegerp 0250
 219
 220 #define BRgoto 0252
 221 #define BRgotoifnil 0253
 222 #define BRgotoifnonnil 0254
 223 #define BRgotoifnilelsepop 0255
 224 #define BRgotoifnonnilelsepop 0256
 225
 226 #define BlistN 0257
 227 #define BconcatN 0260
 228 #define BinsertN 0261
 229
 230 #define Bconstant 0300
 231 #define CONSTANTLIM 0100
 232
 233 \f
 234 /* Structure describing a value stack used during byte-code execution
 235    in Fbyte_code.  */
 236
 237 struct byte_stack
 238 {
 239   /* Program counter.  This points into the byte_string below
 240      and is relocated when that string is relocated.  */
 241   unsigned char *pc;
 242
 243   /* Top and bottom of stack.  The bottom points to an area of memory
 244      allocated with alloca in Fbyte_code.  */
 245   Lisp_Object *top, *bottom;
 246
 247   /* The string containing the byte-code, and its current address.
 248      Storing this here protects it from GC because mark_byte_stack
 249      marks it.  */
 250   Lisp_Object byte_string;
 251   unsigned char *byte_string_start;
 252
 253   /* The vector of constants used during byte-code execution.  Storing
 254      this here protects it from GC because mark_byte_stack marks it.  */
 255   Lisp_Object constants;
 256
 257   /* Next entry in byte_stack_list.  */
 258   struct byte_stack *next;
 259 };
 260
 261 /* A list of currently active byte-code execution value stacks.
 262    Fbyte_code adds an entry to the head of this list before it starts
 263    processing byte-code, and it removed the entry again when it is
 264    done.  Signalling an error truncates the list analoguous to
 265    gcprolist.  */
 266
 267 struct byte_stack *byte_stack_list;
 268
 269 \f
 270 /* Mark objects on byte_stack_list.  Called during GC.  */
 271
 272 void
 273 mark_byte_stack ()
 274 {
 275   struct byte_stack *stack;
 276   Lisp_Object *obj;
 277
 278   for (stack = byte_stack_list; stack; stack = stack->next)
 279     {
 280       /* If STACK->top is null here, this means there's an opcode in
 281          Fbyte_code that wasn't expected to GC, but did.  To find out
 282          which opcode this is, record the value of `stack', and walk
 283          up the stack in a debugger, stopping in frames of Fbyte_code.
 284          The culprit is found in the frame of Fbyte_code where the
 285          address of its local variable `stack' is equal to the
 286          recorded value of `stack' here.  */
 287       if (!stack->top)
 288         abort ();
 289
 290       for (obj = stack->bottom; obj <= stack->top; ++obj)
 291         if (!XMARKBIT (*obj))
 292           {
 293             mark_object (obj);
 294             XMARK (*obj);
 295           }
 296
 297       if (!XMARKBIT (stack->byte_string))
 298         {
 299           mark_object (&stack->byte_string);
 300           XMARK (stack->byte_string);
 301         }
 302
 303       if (!XMARKBIT (stack->constants))
 304         {
 305           mark_object (&stack->constants);
 306           XMARK (stack->constants);
 307         }
 308     }
 309 }
 310
 311
 312 /* Unmark objects in the stacks on byte_stack_list.  Relocate program
 313    counters.  Called when GC has completed.  */
 314
 315 void
 316 unmark_byte_stack ()
 317 {
 318   struct byte_stack *stack;
 319   Lisp_Object *obj;
 320
 321   for (stack = byte_stack_list; stack; stack = stack->next)
 322     {
 323       for (obj = stack->bottom; obj <= stack->top; ++obj)
 324         XUNMARK (*obj);
 325
 326       XUNMARK (stack->byte_string);
 327       XUNMARK (stack->constants);
 328
 329       if (stack->byte_string_start != XSTRING (stack->byte_string)->data)
 330         {
 331           int offset = stack->pc - stack->byte_string_start;
 332           stack->byte_string_start = XSTRING (stack->byte_string)->data;
 333           stack->pc = stack->byte_string_start + offset;
 334         }
 335     }
 336 }
 337
 338 \f
 339 /* Fetch the next byte from the bytecode stream */
 340
 341 #define FETCH *stack.pc++
 342
 343 /* Fetch two bytes from the bytecode stream and make a 16-bit number
 344    out of them */
 345
 346 #define FETCH2 (op = FETCH, op + (FETCH << 8))
 347
 348 /* Push x onto the execution stack.  This used to be #define PUSH(x)
 349    (*++stackp = (x)) This oddity is necessary because Alliant can't be
 350    bothered to compile the preincrement operator properly, as of 4/91.
 351    -JimB */
 352
 353 #define PUSH(x) (top++, *top = (x))
 354
 355 /* Pop a value off the execution stack.  */
 356
 357 #define POP (*top--)
 358
 359 /* Discard n values from the execution stack.  */
 360
 361 #define DISCARD(n) (top -= (n))
 362
 363 /* Get the value which is at the top of the execution stack, but don't
 364    pop it. */
 365
 366 #define TOP (*top)
 367
 368 /* Actions that must be performed before and after calling a function
 369    that might GC.  */
 370
 371 #define BEFORE_POTENTIAL_GC()   stack.top = top
 372 #define AFTER_POTENTIAL_GC()    stack.top = NULL
 373
 374 /* Garbage collect if we have consed enough since the last time.
 375    We do this at every branch, to avoid loops that never GC.  */
 376
 377 #define MAYBE_GC()                              \
 378   if (consing_since_gc > gc_cons_threshold)     \
 379     {                                           \
 380       BEFORE_POTENTIAL_GC ();                   \
 381       Fgarbage_collect ();                      \
 382       AFTER_POTENTIAL_GC ();                    \
 383     }                                           \
 384   else
 385
 386 /* Check for jumping out of range.  */
 387
 388 #ifdef BYTE_CODE_SAFE
 389
 390 #define CHECK_RANGE(ARG) \
 391   if (ARG >= bytestr_length) abort ()
 392
 393 #else /* not BYTE_CODE_SAFE */
 394
 395 #define CHECK_RANGE(ARG)
 396
 397 #endif /* not BYTE_CODE_SAFE */
 398
 399
 400 DEFUN ("byte-code", Fbyte_code, Sbyte_code, 3, 3, 0,
 401   "Function used internally in byte-compiled code.\n\
 402 The first argument, BYTESTR, is a string of byte code;\n\
 403 the second, VECTOR, a vector of constants;\n\
 404 the third, MAXDEPTH, the maximum stack depth used in this function.\n\
 405 If the third argument is incorrect, Emacs may crash.")
 406   (bytestr, vector, maxdepth)
 407      Lisp_Object bytestr, vector, maxdepth;
 408 {
 409   int count = specpdl_ptr - specpdl;
 410 #ifdef BYTE_CODE_METER
 411   int this_op = 0;
 412   int prev_op;
 413 #endif
 414   int op;
 415   /* Lisp_Object v1, v2; */
 416   Lisp_Object *vectorp;
 417 #ifdef BYTE_CODE_SAFE
 418   int const_length = XVECTOR (vector)->size;
 419   Lisp_Object *stacke;
 420 #endif
 421   int bytestr_length;
 422   struct byte_stack stack;
 423   Lisp_Object *top;
 424   Lisp_Object result;
 425
 426 #ifdef CHECK_FRAME_FONT
 427  {
 428    struct frame *f = SELECTED_FRAME ();
 429    if (FRAME_X_P (f)
 430        && FRAME_FONT (f)->direction != 0
 431        && FRAME_FONT (f)->direction != 1)
 432      abort ();
 433  }
 434 #endif
 435
 436   CHECK_STRING (bytestr, 0);
 437   if (!VECTORP (vector))
 438     vector = wrong_type_argument (Qvectorp, vector);
 439   CHECK_NUMBER (maxdepth, 2);
 440
 441   if (STRING_MULTIBYTE (bytestr))
 442     /* BYTESTR must have been produced by Emacs 20.2 or the earlier
 443        because they produced a raw 8-bit string for byte-code and now
 444        such a byte-code string is loaded as multibyte while raw 8-bit
 445        characters converted to multibyte form.  Thus, now we must
 446        convert them back to the original unibyte form.  */
 447     bytestr = Fstring_as_unibyte (bytestr);
 448
 449   bytestr_length = STRING_BYTES (XSTRING (bytestr));
 450   vectorp = XVECTOR (vector)->contents;
 451
 452   stack.byte_string = bytestr;
 453   stack.pc = stack.byte_string_start = XSTRING (bytestr)->data;
 454   stack.constants = vector;
 455   stack.bottom = (Lisp_Object *) alloca (XFASTINT (maxdepth)
 456                                          * sizeof (Lisp_Object));
 457   top = stack.bottom - 1;
 458   stack.top = NULL;
 459   stack.next = byte_stack_list;
 460   byte_stack_list = &stack;
 461
 462 #ifdef BYTE_CODE_SAFE
 463   stacke = stack.bottom - 1 + XFASTINT (maxdepth);
 464 #endif
 465
 466   while (1)
 467     {
 468 #ifdef BYTE_CODE_SAFE
 469       if (top > stacke)
 470         abort ();
 471       else if (top < stack.bottom - 1)
 472         abort ();
 473 #endif
 474
 475 #ifdef BYTE_CODE_METER
 476       prev_op = this_op;
 477       this_op = op = FETCH;
 478       METER_CODE (prev_op, op);
 479 #else
 480       op = FETCH;
 481 #endif
 482
 483       switch (op)
 484         {
 485         case Bvarref + 7:
 486           op = FETCH2;
 487           goto varref;
 488
 489         case Bvarref:
 490         case Bvarref + 1:
 491         case Bvarref + 2:
 492         case Bvarref + 3:
 493         case Bvarref + 4:
 494         case Bvarref + 5:
 495           op = op - Bvarref;
 496           goto varref;
 497
 498         /* This seems to be the most frequently executed byte-code
 499            among the Bvarref's, so avoid a goto here.  */
 500         case Bvarref+6:
 501           op = FETCH;
 502         varref:
 503           {
 504             Lisp_Object v1, v2;
 505
 506             v1 = vectorp[op];
 507             if (SYMBOLP (v1))
 508               {
 509                 v2 = XSYMBOL (v1)->value;
 510                 if (MISCP (v2) || EQ (v2, Qunbound))
 511                   {
 512                     BEFORE_POTENTIAL_GC ();
 513                     v2 = Fsymbol_value (v1);
 514                     AFTER_POTENTIAL_GC ();
 515                   }
 516               }
 517             else
 518               {
 519                 BEFORE_POTENTIAL_GC ();
 520                 v2 = Fsymbol_value (v1);
 521                 AFTER_POTENTIAL_GC ();
 522               }
 523             PUSH (v2);
 524             break;
 525           }
 526
 527         case Bgotoifnil:
 528           MAYBE_GC ();
 529           op = FETCH2;
 530           if (NILP (POP))
 531             {
 532               QUIT;
 533               CHECK_RANGE (op);
 534               stack.pc = stack.byte_string_start + op;
 535             }
 536           break;
 537
 538         case Bcar:
 539           {
 540             Lisp_Object v1;
 541             v1 = TOP;
 542             if (CONSP (v1))
 543               TOP = XCAR (v1);
 544             else if (NILP (v1))
 545               TOP = Qnil;
 546             else
 547               {
 548                 BEFORE_POTENTIAL_GC ();
 549                 Fcar (wrong_type_argument (Qlistp, v1));
 550                 AFTER_POTENTIAL_GC ();
 551               }
 552             break;
 553           }
 554
 555         case Beq:
 556           {
 557             Lisp_Object v1;
 558             v1 = POP;
 559             TOP = EQ (v1, TOP) ? Qt : Qnil;
 560             break;
 561           }
 562
 563         case Bmemq:
 564           {
 565             Lisp_Object v1;
 566             BEFORE_POTENTIAL_GC ();
 567             v1 = POP;
 568             TOP = Fmemq (TOP, v1);
 569             AFTER_POTENTIAL_GC ();
 570             break;
 571           }
 572
 573         case Bcdr:
 574           {
 575             Lisp_Object v1;
 576             v1 = TOP;
 577             if (CONSP (v1))
 578               TOP = XCDR (v1);
 579             else if (NILP (v1))
 580               TOP = Qnil;
 581             else
 582               {
 583                 BEFORE_POTENTIAL_GC ();
 584                 Fcdr (wrong_type_argument (Qlistp, v1));
 585                 AFTER_POTENTIAL_GC ();
 586               }
 587             break;
 588           }
 589
 590         case Bvarset:
 591         case Bvarset+1:
 592         case Bvarset+2:
 593         case Bvarset+3:
 594         case Bvarset+4:
 595         case Bvarset+5:
 596           op -= Bvarset;
 597           goto varset;
 598
 599         case Bvarset+7:
 600           op = FETCH2;
 601           goto varset;
 602
 603         case Bvarset+6:
 604           op = FETCH;
 605         varset:
 606           {
 607             Lisp_Object sym, val;
 608
 609             sym = vectorp[op];
 610             val = TOP;
 611
 612             /* Inline the most common case.  */
 613             if (SYMBOLP (sym)
 614                 && !EQ (val, Qunbound)
 615                 && !MISCP (XSYMBOL (sym)->value)
 616                 /* I think this should either be checked in the byte
 617                    compiler, or there should be a flag indicating that
 618                    a symbol might be constant in Lisp_Symbol, instead
 619                    of checking this here over and over again. --gerd.  */
 620                 && !EQ (sym, Qnil)
 621                 && !EQ (sym, Qt)
 622                 && !(XSYMBOL (sym)->name->data[0] == ':'
 623                      && EQ (XSYMBOL (sym)->obarray, initial_obarray)
 624                      && !EQ (val, sym)))
 625               XSYMBOL (sym)->value = val;
 626             else
 627               {
 628                 BEFORE_POTENTIAL_GC ();
 629                 set_internal (sym, val, current_buffer, 0);
 630                 AFTER_POTENTIAL_GC ();
 631               }
 632           }
 633           POP;
 634           break;
 635
 636         case Bdup:
 637           {
 638             Lisp_Object v1;
 639             v1 = TOP;
 640             PUSH (v1);
 641             break;
 642           }
 643
 644         /* ------------------ */
 645
 646         case Bvarbind+6:
 647           op = FETCH;
 648           goto varbind;
 649
 650         case Bvarbind+7:
 651           op = FETCH2;
 652           goto varbind;
 653
 654         case Bvarbind:
 655         case Bvarbind+1:
 656         case Bvarbind+2:
 657         case Bvarbind+3:
 658         case Bvarbind+4:
 659         case Bvarbind+5:
 660           op -= Bvarbind;
 661         varbind:
 662           /* Specbind can signal and thus GC.  */
 663           BEFORE_POTENTIAL_GC ();
 664           specbind (vectorp[op], POP);
 665           AFTER_POTENTIAL_GC ();
 666           break;
 667
 668         case Bcall+6:
 669           op = FETCH;
 670           goto docall;
 671
 672         case Bcall+7:
 673           op = FETCH2;
 674           goto docall;
 675
 676         case Bcall:
 677         case Bcall+1:
 678         case Bcall+2:
 679         case Bcall+3:
 680         case Bcall+4:
 681         case Bcall+5:
 682           op -= Bcall;
 683         docall:
 684           {
 685             BEFORE_POTENTIAL_GC ();
 686             DISCARD (op);
 687 #ifdef BYTE_CODE_METER
 688             if (byte_metering_on && SYMBOLP (TOP))
 689               {
 690                 Lisp_Object v1, v2;
 691
 692                 v1 = TOP;
 693                 v2 = Fget (v1, Qbyte_code_meter);
 694                 if (INTEGERP (v2)
 695                     && XINT (v2) != ((1<<VALBITS)-1))
 696                   {
 697                     XSETINT (v2, XINT (v2) + 1);
 698                     Fput (v1, Qbyte_code_meter, v2);
 699                   }
 700               }
 701 #endif
 702             TOP = Ffuncall (op + 1, &TOP);
 703             AFTER_POTENTIAL_GC ();
 704             break;
 705           }
 706
 707         case Bunbind+6:
 708           op = FETCH;
 709           goto dounbind;
 710
 711         case Bunbind+7:
 712           op = FETCH2;
 713           goto dounbind;
 714
 715         case Bunbind:
 716         case Bunbind+1:
 717         case Bunbind+2:
 718         case Bunbind+3:
 719         case Bunbind+4:
 720         case Bunbind+5:
 721           op -= Bunbind;
 722         dounbind:
 723           BEFORE_POTENTIAL_GC ();
 724           unbind_to (specpdl_ptr - specpdl - op, Qnil);
 725           AFTER_POTENTIAL_GC ();
 726           break;
 727
 728         case Bunbind_all:
 729           /* To unbind back to the beginning of this frame.  Not used yet,
 730              but will be needed for tail-recursion elimination.  */
 731           BEFORE_POTENTIAL_GC ();
 732           unbind_to (count, Qnil);
 733           AFTER_POTENTIAL_GC ();
 734           break;
 735
 736         case Bgoto:
 737           MAYBE_GC ();
 738           QUIT;
 739           op = FETCH2;    /* pc = FETCH2 loses since FETCH2 contains pc++ */
 740           CHECK_RANGE (op);
 741           stack.pc = stack.byte_string_start + op;
 742           break;
 743
 744         case Bgotoifnonnil:
 745           MAYBE_GC ();
 746           op = FETCH2;
 747           if (!NILP (POP))
 748             {
 749               QUIT;
 750               CHECK_RANGE (op);
 751               stack.pc = stack.byte_string_start + op;
 752             }
 753           break;
 754
 755         case Bgotoifnilelsepop:
 756           MAYBE_GC ();
 757           op = FETCH2;
 758           if (NILP (TOP))
 759             {
 760               QUIT;
 761               CHECK_RANGE (op);
 762               stack.pc = stack.byte_string_start + op;
 763             }
 764           else DISCARD (1);
 765           break;
 766
 767         case Bgotoifnonnilelsepop:
 768           MAYBE_GC ();
 769           op = FETCH2;
 770           if (!NILP (TOP))
 771             {
 772               QUIT;
 773               CHECK_RANGE (op);
 774               stack.pc = stack.byte_string_start + op;
 775             }
 776           else DISCARD (1);
 777           break;
 778
 779         case BRgoto:
 780           MAYBE_GC ();
 781           QUIT;
 782           stack.pc += (int) *stack.pc - 127;
 783           break;
 784
 785         case BRgotoifnil:
 786           MAYBE_GC ();
 787           if (NILP (POP))
 788             {
 789               QUIT;
 790               stack.pc += (int) *stack.pc - 128;
 791             }
 792           stack.pc++;
 793           break;
 794
 795         case BRgotoifnonnil:
 796           MAYBE_GC ();
 797           if (!NILP (POP))
 798             {
 799               QUIT;
 800               stack.pc += (int) *stack.pc - 128;
 801             }
 802           stack.pc++;
 803           break;
 804
 805         case BRgotoifnilelsepop:
 806           MAYBE_GC ();
 807           op = *stack.pc++;
 808           if (NILP (TOP))
 809             {
 810               QUIT;
 811               stack.pc += op - 128;
 812             }
 813           else DISCARD (1);
 814           break;
 815
 816         case BRgotoifnonnilelsepop:
 817           MAYBE_GC ();
 818           op = *stack.pc++;
 819           if (!NILP (TOP))
 820             {
 821               QUIT;
 822               stack.pc += op - 128;
 823             }
 824           else DISCARD (1);
 825           break;
 826
 827         case Breturn:
 828           result = POP;
 829           goto exit;
 830
 831         case Bdiscard:
 832           DISCARD (1);
 833           break;
 834
 835         case Bconstant2:
 836           PUSH (vectorp[FETCH2]);
 837           break;
 838
 839         case Bsave_excursion:
 840           record_unwind_protect (save_excursion_restore,
 841                                  save_excursion_save ());
 842           break;
 843
 844         case Bsave_current_buffer:
 845         case Bsave_current_buffer_1:
 846           record_unwind_protect (set_buffer_if_live, Fcurrent_buffer ());
 847           break;
 848
 849         case Bsave_window_excursion:
 850           BEFORE_POTENTIAL_GC ();
 851           TOP = Fsave_window_excursion (TOP);
 852           AFTER_POTENTIAL_GC ();
 853           break;
 854
 855         case Bsave_restriction:
 856           record_unwind_protect (save_restriction_restore,
 857                                  save_restriction_save ());
 858           break;
 859
 860         case Bcatch:
 861           {
 862             Lisp_Object v1;
 863             BEFORE_POTENTIAL_GC ();
 864             v1 = POP;
 865             TOP = internal_catch (TOP, Feval, v1);
 866             AFTER_POTENTIAL_GC ();
 867             break;
 868           }
 869
 870         case Bunwind_protect:
 871           /* The function record_unwind_protect can GC.  */
 872           BEFORE_POTENTIAL_GC ();
 873           record_unwind_protect (0, POP);
 874           AFTER_POTENTIAL_GC ();
 875           (specpdl_ptr - 1)->symbol = Qnil;
 876           break;
 877
 878         case Bcondition_case:
 879           {
 880             Lisp_Object v1;
 881             v1 = POP;
 882             v1 = Fcons (POP, v1);
 883             BEFORE_POTENTIAL_GC ();
 884             TOP = Fcondition_case (Fcons (TOP, v1));
 885             AFTER_POTENTIAL_GC ();
 886             break;
 887           }
 888
 889         case Btemp_output_buffer_setup:
 890           BEFORE_POTENTIAL_GC ();
 891           temp_output_buffer_setup (XSTRING (TOP)->data);
 892           AFTER_POTENTIAL_GC ();
 893           TOP = Vstandard_output;
 894           break;
 895
 896         case Btemp_output_buffer_show:
 897           {
 898             Lisp_Object v1;
 899             BEFORE_POTENTIAL_GC ();
 900             v1 = POP;
 901             temp_output_buffer_show (TOP);
 902             TOP = v1;
 903             /* pop binding of standard-output */
 904             unbind_to (specpdl_ptr - specpdl - 1, Qnil);
 905             AFTER_POTENTIAL_GC ();
 906             break;
 907           }
 908
 909         case Bnth:
 910           {
 911             Lisp_Object v1, v2;
 912             BEFORE_POTENTIAL_GC ();
 913             v1 = POP;
 914             v2 = TOP;
 915             CHECK_NUMBER (v2, 0);
 916             AFTER_POTENTIAL_GC ();
 917             op = XINT (v2);
 918             immediate_quit = 1;
 919             while (--op >= 0)
 920               {
 921                 if (CONSP (v1))
 922                   v1 = XCDR (v1);
 923                 else if (!NILP (v1))
 924                   {
 925                     immediate_quit = 0;
 926                     BEFORE_POTENTIAL_GC ();
 927                     v1 = wrong_type_argument (Qlistp, v1);
 928                     AFTER_POTENTIAL_GC ();
 929                     immediate_quit = 1;
 930                     op++;
 931                   }
 932               }
 933             immediate_quit = 0;
 934             if (CONSP (v1))
 935               TOP = XCAR (v1);
 936             else if (NILP (v1))
 937               TOP = Qnil;
 938             else
 939               {
 940                 BEFORE_POTENTIAL_GC ();
 941                 Fcar (wrong_type_argument (Qlistp, v1));
 942                 AFTER_POTENTIAL_GC ();
 943               }
 944             break;
 945           }
 946
 947         case Bsymbolp:
 948           TOP = SYMBOLP (TOP) ? Qt : Qnil;
 949           break;
 950
 951         case Bconsp:
 952           TOP = CONSP (TOP) ? Qt : Qnil;
 953           break;
 954
 955         case Bstringp:
 956           TOP = STRINGP (TOP) ? Qt : Qnil;
 957           break;
 958
 959         case Blistp:
 960           TOP = CONSP (TOP) || NILP (TOP) ? Qt : Qnil;
 961           break;
 962
 963         case Bnot:
 964           TOP = NILP (TOP) ? Qt : Qnil;
 965           break;
 966
 967         case Bcons:
 968           {
 969             Lisp_Object v1;
 970             v1 = POP;
 971             TOP = Fcons (TOP, v1);
 972             break;
 973           }
 974
 975         case Blist1:
 976           TOP = Fcons (TOP, Qnil);
 977           break;
 978
 979         case Blist2:
 980           {
 981             Lisp_Object v1;
 982             v1 = POP;
 983             TOP = Fcons (TOP, Fcons (v1, Qnil));
 984             break;
 985           }
 986
 987         case Blist3:
 988           DISCARD (2);
 989           TOP = Flist (3, &TOP);
 990           break;
 991
 992         case Blist4:
 993           DISCARD (3);
 994           TOP = Flist (4, &TOP);
 995           break;
 996
 997         case BlistN:
 998           op = FETCH;
 999           DISCARD (op - 1);
1000           TOP = Flist (op, &TOP);
1001           break;
1002
1003         case Blength:
1004           BEFORE_POTENTIAL_GC ();
1005           TOP = Flength (TOP);
1006           AFTER_POTENTIAL_GC ();
1007           break;
1008
1009         case Baref:
1010           {
1011             Lisp_Object v1;
1012             BEFORE_POTENTIAL_GC ();
1013             v1 = POP;
1014             TOP = Faref (TOP, v1);
1015             AFTER_POTENTIAL_GC ();
1016             break;
1017           }
1018
1019         case Baset:
1020           {
1021             Lisp_Object v1, v2;
1022             BEFORE_POTENTIAL_GC ();
1023             v2 = POP; v1 = POP;
1024             TOP = Faset (TOP, v1, v2);
1025             AFTER_POTENTIAL_GC ();
1026             break;
1027           }
1028
1029         case Bsymbol_value:
1030           BEFORE_POTENTIAL_GC ();
1031           TOP = Fsymbol_value (TOP);
1032           AFTER_POTENTIAL_GC ();
1033           break;
1034
1035         case Bsymbol_function:
1036           BEFORE_POTENTIAL_GC ();
1037           TOP = Fsymbol_function (TOP);
1038           AFTER_POTENTIAL_GC ();
1039           break;
1040
1041         case Bset:
1042           {
1043             Lisp_Object v1;
1044             BEFORE_POTENTIAL_GC ();
1045             v1 = POP;
1046             TOP = Fset (TOP, v1);
1047             AFTER_POTENTIAL_GC ();
1048             break;
1049           }
1050
1051         case Bfset:
1052           {
1053             Lisp_Object v1;
1054             BEFORE_POTENTIAL_GC ();
1055             v1 = POP;
1056             TOP = Ffset (TOP, v1);
1057             AFTER_POTENTIAL_GC ();
1058             break;
1059           }
1060
1061         case Bget:
1062           {
1063             Lisp_Object v1;
1064             BEFORE_POTENTIAL_GC ();
1065             v1 = POP;
1066             TOP = Fget (TOP, v1);
1067             AFTER_POTENTIAL_GC ();
1068             break;
1069           }
1070
1071         case Bsubstring:
1072           {
1073             Lisp_Object v1, v2;
1074             BEFORE_POTENTIAL_GC ();
1075             v2 = POP; v1 = POP;
1076             TOP = Fsubstring (TOP, v1, v2);
1077             AFTER_POTENTIAL_GC ();
1078             break;
1079           }
1080
1081         case Bconcat2:
1082           BEFORE_POTENTIAL_GC ();
1083           DISCARD (1);
1084           TOP = Fconcat (2, &TOP);
1085           AFTER_POTENTIAL_GC ();
1086           break;
1087
1088         case Bconcat3:
1089           BEFORE_POTENTIAL_GC ();
1090           DISCARD (2);
1091           TOP = Fconcat (3, &TOP);
1092           AFTER_POTENTIAL_GC ();
1093           break;
1094
1095         case Bconcat4:
1096           BEFORE_POTENTIAL_GC ();
1097           DISCARD (3);
1098           TOP = Fconcat (4, &TOP);
1099           AFTER_POTENTIAL_GC ();
1100           break;
1101
1102         case BconcatN:
1103           op = FETCH;
1104           BEFORE_POTENTIAL_GC ();
1105           DISCARD (op - 1);
1106           TOP = Fconcat (op, &TOP);
1107           AFTER_POTENTIAL_GC ();
1108           break;
1109
1110         case Bsub1:
1111           {
1112             Lisp_Object v1;
1113             v1 = TOP;
1114             if (INTEGERP (v1))
1115               {
1116                 XSETINT (v1, XINT (v1) - 1);
1117                 TOP = v1;
1118               }
1119             else
1120               TOP = Fsub1 (v1);
1121             break;
1122           }
1123
1124         case Badd1:
1125           {
1126             Lisp_Object v1;
1127             v1 = TOP;
1128             if (INTEGERP (v1))
1129               {
1130                 XSETINT (v1, XINT (v1) + 1);
1131                 TOP = v1;
1132               }
1133             else
1134               {
1135                 BEFORE_POTENTIAL_GC ();
1136                 TOP = Fadd1 (v1);
1137                 AFTER_POTENTIAL_GC ();
1138               }
1139             break;
1140           }
1141
1142         case Beqlsign:
1143           {
1144             Lisp_Object v1, v2;
1145             BEFORE_POTENTIAL_GC ();
1146             v2 = POP; v1 = TOP;
1147             CHECK_NUMBER_OR_FLOAT_COERCE_MARKER (v1, 0);
1148             CHECK_NUMBER_OR_FLOAT_COERCE_MARKER (v2, 0);
1149             AFTER_POTENTIAL_GC ();
1150             if (FLOATP (v1) || FLOATP (v2))
1151               {
1152                 double f1, f2;
1153
1154                 f1 = (FLOATP (v1) ? XFLOAT_DATA (v1) : XINT (v1));
1155                 f2 = (FLOATP (v2) ? XFLOAT_DATA (v2) : XINT (v2));
1156                 TOP = (f1 == f2 ? Qt : Qnil);
1157               }
1158             else
1159               TOP = (XINT (v1) == XINT (v2) ? Qt : Qnil);
1160             break;
1161           }
1162
1163         case Bgtr:
1164           {
1165             Lisp_Object v1;
1166             BEFORE_POTENTIAL_GC ();
1167             v1 = POP;
1168             TOP = Fgtr (TOP, v1);
1169             AFTER_POTENTIAL_GC ();
1170             break;
1171           }
1172
1173         case Blss:
1174           {
1175             Lisp_Object v1;
1176             BEFORE_POTENTIAL_GC ();
1177             v1 = POP;
1178             TOP = Flss (TOP, v1);
1179             AFTER_POTENTIAL_GC ();
1180             break;
1181           }
1182
1183         case Bleq:
1184           {
1185             Lisp_Object v1;
1186             BEFORE_POTENTIAL_GC ();
1187             v1 = POP;
1188             TOP = Fleq (TOP, v1);
1189             AFTER_POTENTIAL_GC ();
1190             break;
1191           }
1192
1193         case Bgeq:
1194           {
1195             Lisp_Object v1;
1196             BEFORE_POTENTIAL_GC ();
1197             v1 = POP;
1198             TOP = Fgeq (TOP, v1);
1199             AFTER_POTENTIAL_GC ();
1200             break;
1201           }
1202
1203         case Bdiff:
1204           BEFORE_POTENTIAL_GC ();
1205           DISCARD (1);
1206           TOP = Fminus (2, &TOP);
1207           AFTER_POTENTIAL_GC ();
1208           break;
1209
1210         case Bnegate:
1211           {
1212             Lisp_Object v1;
1213             v1 = TOP;
1214             if (INTEGERP (v1))
1215               {
1216                 XSETINT (v1, - XINT (v1));
1217                 TOP = v1;
1218               }
1219             else
1220               {
1221                 BEFORE_POTENTIAL_GC ();
1222                 TOP = Fminus (1, &TOP);
1223                 AFTER_POTENTIAL_GC ();
1224               }
1225             break;
1226           }
1227
1228         case Bplus:
1229           BEFORE_POTENTIAL_GC ();
1230           DISCARD (1);
1231           TOP = Fplus (2, &TOP);
1232           AFTER_POTENTIAL_GC ();
1233           break;
1234
1235         case Bmax:
1236           BEFORE_POTENTIAL_GC ();
1237           DISCARD (1);
1238           TOP = Fmax (2, &TOP);
1239           AFTER_POTENTIAL_GC ();
1240           break;
1241
1242         case Bmin:
1243           BEFORE_POTENTIAL_GC ();
1244           DISCARD (1);
1245           TOP = Fmin (2, &TOP);
1246           AFTER_POTENTIAL_GC ();
1247           break;
1248
1249         case Bmult:
1250           BEFORE_POTENTIAL_GC ();
1251           DISCARD (1);
1252           TOP = Ftimes (2, &TOP);
1253           AFTER_POTENTIAL_GC ();
1254           break;
1255
1256         case Bquo:
1257           BEFORE_POTENTIAL_GC ();
1258           DISCARD (1);
1259           TOP = Fquo (2, &TOP);
1260           AFTER_POTENTIAL_GC ();
1261           break;
1262
1263         case Brem:
1264           {
1265             Lisp_Object v1;
1266             BEFORE_POTENTIAL_GC ();
1267             v1 = POP;
1268             TOP = Frem (TOP, v1);
1269             AFTER_POTENTIAL_GC ();
1270             break;
1271           }
1272
1273         case Bpoint:
1274           {
1275             Lisp_Object v1;
1276             XSETFASTINT (v1, PT);
1277             PUSH (v1);
1278             break;
1279           }
1280
1281         case Bgoto_char:
1282           BEFORE_POTENTIAL_GC ();
1283           TOP = Fgoto_char (TOP);
1284           AFTER_POTENTIAL_GC ();
1285           break;
1286
1287         case Binsert:
1288           BEFORE_POTENTIAL_GC ();
1289           TOP = Finsert (1, &TOP);
1290           AFTER_POTENTIAL_GC ();
1291           break;
1292
1293         case BinsertN:
1294           op = FETCH;
1295           BEFORE_POTENTIAL_GC ();
1296           DISCARD (op - 1);
1297           TOP = Finsert (op, &TOP);
1298           AFTER_POTENTIAL_GC ();
1299           break;
1300
1301         case Bpoint_max:
1302           {
1303             Lisp_Object v1;
1304             XSETFASTINT (v1, ZV);
1305             PUSH (v1);
1306             break;
1307           }
1308
1309         case Bpoint_min:
1310           {
1311             Lisp_Object v1;
1312             XSETFASTINT (v1, BEGV);
1313             PUSH (v1);
1314             break;
1315           }
1316
1317         case Bchar_after:
1318           BEFORE_POTENTIAL_GC ();
1319           TOP = Fchar_after (TOP);
1320           AFTER_POTENTIAL_GC ();
1321           break;
1322
1323         case Bfollowing_char:
1324           {
1325             Lisp_Object v1;
1326             BEFORE_POTENTIAL_GC ();
1327             v1 = Ffollowing_char ();
1328             AFTER_POTENTIAL_GC ();
1329             PUSH (v1);
1330             break;
1331           }
1332
1333         case Bpreceding_char:
1334           {
1335             Lisp_Object v1;
1336             BEFORE_POTENTIAL_GC ();
1337             v1 = Fprevious_char ();
1338             AFTER_POTENTIAL_GC ();
1339             PUSH (v1);
1340             break;
1341           }
1342
1343         case Bcurrent_column:
1344           {
1345             Lisp_Object v1;
1346             BEFORE_POTENTIAL_GC ();
1347             XSETFASTINT (v1, current_column ());
1348             AFTER_POTENTIAL_GC ();
1349             PUSH (v1);
1350             break;
1351           }
1352
1353         case Bindent_to:
1354           BEFORE_POTENTIAL_GC ();
1355           TOP = Findent_to (TOP, Qnil);
1356           AFTER_POTENTIAL_GC ();
1357           break;
1358
1359         case Beolp:
1360           PUSH (Feolp ());
1361           break;
1362
1363         case Beobp:
1364           PUSH (Feobp ());
1365           break;
1366
1367         case Bbolp:
1368           PUSH (Fbolp ());
1369           break;
1370
1371         case Bbobp:
1372           PUSH (Fbobp ());
1373           break;
1374
1375         case Bcurrent_buffer:
1376           PUSH (Fcurrent_buffer ());
1377           break;
1378
1379         case Bset_buffer:
1380           BEFORE_POTENTIAL_GC ();
1381           TOP = Fset_buffer (TOP);
1382           AFTER_POTENTIAL_GC ();
1383           break;
1384
1385         case Binteractive_p:
1386           PUSH (Finteractive_p ());
1387           break;
1388
1389         case Bforward_char:
1390           BEFORE_POTENTIAL_GC ();
1391           TOP = Fforward_char (TOP);
1392           AFTER_POTENTIAL_GC ();
1393           break;
1394
1395         case Bforward_word:
1396           BEFORE_POTENTIAL_GC ();
1397           TOP = Fforward_word (TOP);
1398           AFTER_POTENTIAL_GC ();
1399           break;
1400
1401         case Bskip_chars_forward:
1402           {
1403             Lisp_Object v1;
1404             BEFORE_POTENTIAL_GC ();
1405             v1 = POP;
1406             TOP = Fskip_chars_forward (TOP, v1);
1407             AFTER_POTENTIAL_GC ();
1408             break;
1409           }
1410
1411         case Bskip_chars_backward:
1412           {
1413             Lisp_Object v1;
1414             BEFORE_POTENTIAL_GC ();
1415             v1 = POP;
1416             TOP = Fskip_chars_backward (TOP, v1);
1417             AFTER_POTENTIAL_GC ();
1418             break;
1419           }
1420
1421         case Bforward_line:
1422           BEFORE_POTENTIAL_GC ();
1423           TOP = Fforward_line (TOP);
1424           AFTER_POTENTIAL_GC ();
1425           break;
1426
1427         case Bchar_syntax:
1428           BEFORE_POTENTIAL_GC ();
1429           CHECK_NUMBER (TOP, 0);
1430           AFTER_POTENTIAL_GC ();
1431           XSETFASTINT (TOP, syntax_code_spec[(int) SYNTAX (XINT (TOP))]);
1432           break;
1433
1434         case Bbuffer_substring:
1435           {
1436             Lisp_Object v1;
1437             BEFORE_POTENTIAL_GC ();
1438             v1 = POP;
1439             TOP = Fbuffer_substring (TOP, v1);
1440             AFTER_POTENTIAL_GC ();
1441             break;
1442           }
1443
1444         case Bdelete_region:
1445           {
1446             Lisp_Object v1;
1447             BEFORE_POTENTIAL_GC ();
1448             v1 = POP;
1449             TOP = Fdelete_region (TOP, v1);
1450             AFTER_POTENTIAL_GC ();
1451             break;
1452           }
1453
1454         case Bnarrow_to_region:
1455           {
1456             Lisp_Object v1;
1457             BEFORE_POTENTIAL_GC ();
1458             v1 = POP;
1459             TOP = Fnarrow_to_region (TOP, v1);
1460             AFTER_POTENTIAL_GC ();
1461             break;
1462           }
1463
1464         case Bwiden:
1465           BEFORE_POTENTIAL_GC ();
1466           PUSH (Fwiden ());
1467           AFTER_POTENTIAL_GC ();
1468           break;
1469
1470         case Bend_of_line:
1471           BEFORE_POTENTIAL_GC ();
1472           TOP = Fend_of_line (TOP);
1473           AFTER_POTENTIAL_GC ();
1474           break;
1475
1476         case Bset_marker:
1477           {
1478             Lisp_Object v1, v2;
1479             BEFORE_POTENTIAL_GC ();
1480             v1 = POP;
1481             v2 = POP;
1482             TOP = Fset_marker (TOP, v2, v1);
1483             AFTER_POTENTIAL_GC ();
1484             break;
1485           }
1486
1487         case Bmatch_beginning:
1488           BEFORE_POTENTIAL_GC ();
1489           TOP = Fmatch_beginning (TOP);
1490           AFTER_POTENTIAL_GC ();
1491           break;
1492
1493         case Bmatch_end:
1494           BEFORE_POTENTIAL_GC ();
1495           TOP = Fmatch_end (TOP);
1496           AFTER_POTENTIAL_GC ();
1497           break;
1498
1499         case Bupcase:
1500           BEFORE_POTENTIAL_GC ();
1501           TOP = Fupcase (TOP);
1502           AFTER_POTENTIAL_GC ();
1503           break;
1504
1505         case Bdowncase:
1506           BEFORE_POTENTIAL_GC ();
1507           TOP = Fdowncase (TOP);
1508           AFTER_POTENTIAL_GC ();
1509         break;
1510
1511         case Bstringeqlsign:
1512           {
1513             Lisp_Object v1;
1514             BEFORE_POTENTIAL_GC ();
1515             v1 = POP;
1516             TOP = Fstring_equal (TOP, v1);
1517             AFTER_POTENTIAL_GC ();
1518             break;
1519           }
1520
1521         case Bstringlss:
1522           {
1523             Lisp_Object v1;
1524             BEFORE_POTENTIAL_GC ();
1525             v1 = POP;
1526             TOP = Fstring_lessp (TOP, v1);
1527             AFTER_POTENTIAL_GC ();
1528             break;
1529           }
1530
1531         case Bequal:
1532           {
1533             Lisp_Object v1;
1534             v1 = POP;
1535             TOP = Fequal (TOP, v1);
1536             break;
1537           }
1538
1539         case Bnthcdr:
1540           {
1541             Lisp_Object v1;
1542             BEFORE_POTENTIAL_GC ();
1543             v1 = POP;
1544             TOP = Fnthcdr (TOP, v1);
1545             AFTER_POTENTIAL_GC ();
1546             break;
1547           }
1548
1549         case Belt:
1550           {
1551             Lisp_Object v1, v2;
1552             if (CONSP (TOP))
1553               {
1554                 /* Exchange args and then do nth.  */
1555                 BEFORE_POTENTIAL_GC ();
1556                 v2 = POP;
1557                 v1 = TOP;
1558                 CHECK_NUMBER (v2, 0);
1559                 AFTER_POTENTIAL_GC ();
1560                 op = XINT (v2);
1561                 immediate_quit = 1;
1562                 while (--op >= 0)
1563                   {
1564                     if (CONSP (v1))
1565                       v1 = XCDR (v1);
1566                     else if (!NILP (v1))
1567                       {
1568                         immediate_quit = 0;
1569                         BEFORE_POTENTIAL_GC ();
1570                         v1 = wrong_type_argument (Qlistp, v1);
1571                         AFTER_POTENTIAL_GC ();
1572                         immediate_quit = 1;
1573                         op++;
1574                       }
1575                   }
1576                 immediate_quit = 0;
1577                 if (CONSP (v1))
1578                   TOP = XCAR (v1);
1579                 else if (NILP (v1))
1580                   TOP = Qnil;
1581                 else
1582                   {
1583                     BEFORE_POTENTIAL_GC ();
1584                     Fcar (wrong_type_argument (Qlistp, v1));
1585                     AFTER_POTENTIAL_GC ();
1586                   }
1587               }
1588             else
1589               {
1590                 BEFORE_POTENTIAL_GC ();
1591                 v1 = POP;
1592                 TOP = Felt (TOP, v1);
1593                 AFTER_POTENTIAL_GC ();
1594               }
1595             break;
1596           }
1597
1598         case Bmember:
1599           {
1600             Lisp_Object v1;
1601             BEFORE_POTENTIAL_GC ();
1602             v1 = POP;
1603             TOP = Fmember (TOP, v1);
1604             AFTER_POTENTIAL_GC ();
1605             break;
1606           }
1607
1608         case Bassq:
1609           {
1610             Lisp_Object v1;
1611             BEFORE_POTENTIAL_GC ();
1612             v1 = POP;
1613             TOP = Fassq (TOP, v1);
1614             AFTER_POTENTIAL_GC ();
1615             break;
1616           }
1617
1618         case Bnreverse:
1619           BEFORE_POTENTIAL_GC ();
1620           TOP = Fnreverse (TOP);
1621           AFTER_POTENTIAL_GC ();
1622           break;
1623
1624         case Bsetcar:
1625           {
1626             Lisp_Object v1;
1627             BEFORE_POTENTIAL_GC ();
1628             v1 = POP;
1629             TOP = Fsetcar (TOP, v1);
1630             AFTER_POTENTIAL_GC ();
1631             break;
1632           }
1633
1634         case Bsetcdr:
1635           {
1636             Lisp_Object v1;
1637             BEFORE_POTENTIAL_GC ();
1638             v1 = POP;
1639             TOP = Fsetcdr (TOP, v1);
1640             AFTER_POTENTIAL_GC ();
1641             break;
1642           }
1643
1644         case Bcar_safe:
1645           {
1646             Lisp_Object v1;
1647             v1 = TOP;
1648             if (CONSP (v1))
1649               TOP = XCAR (v1);
1650             else
1651               TOP = Qnil;
1652             break;
1653           }
1654
1655         case Bcdr_safe:
1656           {
1657             Lisp_Object v1;
1658             v1 = TOP;
1659             if (CONSP (v1))
1660               TOP = XCDR (v1);
1661             else
1662               TOP = Qnil;
1663             break;
1664           }
1665
1666         case Bnconc:
1667           BEFORE_POTENTIAL_GC ();
1668           DISCARD (1);
1669           TOP = Fnconc (2, &TOP);
1670           AFTER_POTENTIAL_GC ();
1671           break;
1672
1673         case Bnumberp:
1674           TOP = (NUMBERP (TOP) ? Qt : Qnil);
1675           break;
1676
1677         case Bintegerp:
1678           TOP = INTEGERP (TOP) ? Qt : Qnil;
1679           break;
1680
1681 #ifdef BYTE_CODE_SAFE
1682         case Bset_mark:
1683           BEFORE_POTENTIAL_GC ();
1684           error ("set-mark is an obsolete bytecode");
1685           AFTER_POTENTIAL_GC ();
1686           break;
1687         case Bscan_buffer:
1688           BEFORE_POTENTIAL_GC ();
1689           error ("scan-buffer is an obsolete bytecode");
1690           AFTER_POTENTIAL_GC ();
1691           break;
1692 #endif
1693
1694         case 0:
1695           abort ();
1696
1697         case 255:
1698         default:
1699 #ifdef BYTE_CODE_SAFE
1700           if (op < Bconstant)
1701             {
1702               abort ();
1703             }
1704           if ((op -= Bconstant) >= const_length)
1705             {
1706               abort ();
1707             }
1708           PUSH (vectorp[op]);
1709 #else
1710           PUSH (vectorp[op - Bconstant]);
1711 #endif
1712         }
1713     }
1714
1715  exit:
1716
1717   byte_stack_list = byte_stack_list->next;
1718
1719   /* Binds and unbinds are supposed to be compiled balanced.  */
1720   if (specpdl_ptr - specpdl != count)
1721 #ifdef BYTE_CODE_SAFE
1722     error ("binding stack not balanced (serious byte compiler bug)");
1723 #else
1724     abort ();
1725 #endif
1726
1727   return result;
1728 }
1729
1730 void
1731 syms_of_bytecode ()
1732 {
1733   Qbytecode = intern ("byte-code");
1734   staticpro (&Qbytecode);
1735
1736   defsubr (&Sbyte_code);
1737
1738 #ifdef BYTE_CODE_METER
1739
1740   DEFVAR_LISP ("byte-code-meter", &Vbyte_code_meter,
1741    "A vector of vectors which holds a histogram of byte-code usage.\n\
1742 (aref (aref byte-code-meter 0) CODE) indicates how many times the byte\n\
1743 opcode CODE has been executed.\n\
1744 (aref (aref byte-code-meter CODE1) CODE2), where CODE1 is not 0,\n\
1745 indicates how many times the byte opcodes CODE1 and CODE2 have been\n\
1746 executed in succession.");
1747   DEFVAR_BOOL ("byte-metering-on", &byte_metering_on,
1748    "If non-nil, keep profiling information on byte code usage.\n\
1749 The variable byte-code-meter indicates how often each byte opcode is used.\n\
1750 If a symbol has a property named `byte-code-meter' whose value is an\n\
1751 integer, it is incremented each time that symbol's function is called.");
1752
1753   byte_metering_on = 0;
1754   Vbyte_code_meter = Fmake_vector (make_number (256), make_number (0));
1755   Qbyte_code_meter = intern ("byte-code-meter");
1756   staticpro (&Qbyte_code_meter);
1757   {
1758     int i = 256;
1759     while (i--)
1760       XVECTOR (Vbyte_code_meter)->contents[i] =
1761         Fmake_vector (make_number (256), make_number (0));
1762   }
1763 #endif
1764 }