src/bytecode.c

   1 /* Execution of byte code produced by bytecomp.el.
   2    Copyright (C) 1985-1988, 1993, 2000-2011 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 3 of the License, or
   9 (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 /*
  20 hacked on by jwz@lucid.com 17-jun-91
  21   o  added a compile-time switch to turn on simple sanity checking;
  22   o  put back the obsolete byte-codes for error-detection;
  23   o  added a new instruction, unbind_all, which I will use for
  24      tail-recursion elimination;
  25   o  made temp_output_buffer_show be called with the right number
  26      of args;
  27   o  made the new bytecodes be called with args in the right order;
  28   o  added metering support.
  29
  30 by Hallvard:
  31   o  added relative jump instructions;
  32   o  all conditionals now only do QUIT if they jump.
  33  */
  34
  35 #include <config.h>
  36 #include <setjmp.h>
  37 #include "lisp.h"
  38 #include "buffer.h"
  39 #include "character.h"
  40 #include "syntax.h"
  41 #include "window.h"
  42
  43 #ifdef CHECK_FRAME_FONT
  44 #include "frame.h"
  45 #include "xterm.h"
  46 #endif
  47
  48 /*
  49  * define BYTE_CODE_SAFE to enable some minor sanity checking (useful for
  50  * debugging the byte compiler...)
  51  *
  52  * define BYTE_CODE_METER to enable generation of a byte-op usage histogram.
  53  */
  54 /* #define BYTE_CODE_SAFE */
  55 /* #define BYTE_CODE_METER */
  56
  57 \f
  58 #ifdef BYTE_CODE_METER
  59
  60 Lisp_Object Qbyte_code_meter;
  61 #define METER_2(code1, code2) \
  62   XFASTINT (XVECTOR (XVECTOR (Vbyte_code_meter)->contents[(code1)]) \
  63             ->contents[(code2)])
  64
  65 #define METER_1(code) METER_2 (0, (code))
  66
  67 #define METER_CODE(last_code, this_code)                                \
  68 {                                                                       \
  69   if (byte_metering_on)                                                 \
  70     {                                                                   \
  71       if (METER_1 (this_code) < MOST_POSITIVE_FIXNUM)                   \
  72         METER_1 (this_code)++;                                          \
  73       if (last_code                                                     \
  74           && METER_2 (last_code, this_code) < MOST_POSITIVE_FIXNUM)     \
  75         METER_2 (last_code, this_code)++;                               \
  76     }                                                                   \
  77 }
  78
  79 #endif /* BYTE_CODE_METER */
  80 \f
  81
  82 Lisp_Object Qbytecode;
  83 extern Lisp_Object Qand_optional, Qand_rest;
  84
  85 /*  Byte codes: */
  86
  87 #define Bstack_ref 0 /* Actually, Bstack_ref+0 is not implemented: use dup.  */
  88 #define Bvarref 010
  89 #define Bvarset 020
  90 #define Bvarbind 030
  91 #define Bcall 040
  92 #define Bunbind 050
  93
  94 #define Bnth 070
  95 #define Bsymbolp 071
  96 #define Bconsp 072
  97 #define Bstringp 073
  98 #define Blistp 074
  99 #define Beq 075
 100 #define Bmemq 076
 101 #define Bnot 077
 102 #define Bcar 0100
 103 #define Bcdr 0101
 104 #define Bcons 0102
 105 #define Blist1 0103
 106 #define Blist2 0104
 107 #define Blist3 0105
 108 #define Blist4 0106
 109 #define Blength 0107
 110 #define Baref 0110
 111 #define Baset 0111
 112 #define Bsymbol_value 0112
 113 #define Bsymbol_function 0113
 114 #define Bset 0114
 115 #define Bfset 0115
 116 #define Bget 0116
 117 #define Bsubstring 0117
 118 #define Bconcat2 0120
 119 #define Bconcat3 0121
 120 #define Bconcat4 0122
 121 #define Bsub1 0123
 122 #define Badd1 0124
 123 #define Beqlsign 0125
 124 #define Bgtr 0126
 125 #define Blss 0127
 126 #define Bleq 0130
 127 #define Bgeq 0131
 128 #define Bdiff 0132
 129 #define Bnegate 0133
 130 #define Bplus 0134
 131 #define Bmax 0135
 132 #define Bmin 0136
 133 #define Bmult 0137
 134
 135 #define Bpoint 0140
 136 /* Was Bmark in v17.  */
 137 #define Bsave_current_buffer 0141 /* Obsolete.  */
 138 #define Bgoto_char 0142
 139 #define Binsert 0143
 140 #define Bpoint_max 0144
 141 #define Bpoint_min 0145
 142 #define Bchar_after 0146
 143 #define Bfollowing_char 0147
 144 #define Bpreceding_char 0150
 145 #define Bcurrent_column 0151
 146 #define Bindent_to 0152
 147 #ifdef BYTE_CODE_SAFE
 148 #define Bscan_buffer 0153 /* No longer generated as of v18 */
 149 #endif
 150 #define Beolp 0154
 151 #define Beobp 0155
 152 #define Bbolp 0156
 153 #define Bbobp 0157
 154 #define Bcurrent_buffer 0160
 155 #define Bset_buffer 0161
 156 #define Bsave_current_buffer_1 0162 /* Replacing Bsave_current_buffer.  */
 157 #if 0
 158 #define Bread_char 0162 /* No longer generated as of v19 */
 159 #endif
 160 #ifdef BYTE_CODE_SAFE
 161 #define Bset_mark 0163 /* this loser is no longer generated as of v18 */
 162 #endif
 163 #define Binteractive_p 0164 /* Obsolete since Emacs-24.1.  */
 164
 165 #define Bforward_char 0165
 166 #define Bforward_word 0166
 167 #define Bskip_chars_forward 0167
 168 #define Bskip_chars_backward 0170
 169 #define Bforward_line 0171
 170 #define Bchar_syntax 0172
 171 #define Bbuffer_substring 0173
 172 #define Bdelete_region 0174
 173 #define Bnarrow_to_region 0175
 174 #define Bwiden 0176
 175 #define Bend_of_line 0177
 176
 177 #define Bconstant2 0201
 178 #define Bgoto 0202
 179 #define Bgotoifnil 0203
 180 #define Bgotoifnonnil 0204
 181 #define Bgotoifnilelsepop 0205
 182 #define Bgotoifnonnilelsepop 0206
 183 #define Breturn 0207
 184 #define Bdiscard 0210
 185 #define Bdup 0211
 186
 187 #define Bsave_excursion 0212
 188 #define Bsave_window_excursion 0213 /* Obsolete since Emacs-24.1.  */
 189 #define Bsave_restriction 0214
 190 #define Bcatch 0215
 191
 192 #define Bunwind_protect 0216
 193 #define Bcondition_case 0217
 194 #define Btemp_output_buffer_setup 0220 /* Obsolete since Emacs-24.1.  */
 195 #define Btemp_output_buffer_show 0221  /* Obsolete since Emacs-24.1.  */
 196
 197 #define Bunbind_all 0222        /* Obsolete.  Never used.  */
 198
 199 #define Bset_marker 0223
 200 #define Bmatch_beginning 0224
 201 #define Bmatch_end 0225
 202 #define Bupcase 0226
 203 #define Bdowncase 0227
 204
 205 #define Bstringeqlsign 0230
 206 #define Bstringlss 0231
 207 #define Bequal 0232
 208 #define Bnthcdr 0233
 209 #define Belt 0234
 210 #define Bmember 0235
 211 #define Bassq 0236
 212 #define Bnreverse 0237
 213 #define Bsetcar 0240
 214 #define Bsetcdr 0241
 215 #define Bcar_safe 0242
 216 #define Bcdr_safe 0243
 217 #define Bnconc 0244
 218 #define Bquo 0245
 219 #define Brem 0246
 220 #define Bnumberp 0247
 221 #define Bintegerp 0250
 222
 223 #define BRgoto 0252
 224 #define BRgotoifnil 0253
 225 #define BRgotoifnonnil 0254
 226 #define BRgotoifnilelsepop 0255
 227 #define BRgotoifnonnilelsepop 0256
 228
 229 #define BlistN 0257
 230 #define BconcatN 0260
 231 #define BinsertN 0261
 232
 233 /* Bstack_ref is code 0.  */
 234 #define Bstack_set  0262
 235 #define Bstack_set2 0263
 236 #define BdiscardN   0266
 237
 238 #define Bconstant 0300
 239
 240 /* Whether to maintain a `top' and `bottom' field in the stack frame.  */
 241 #define BYTE_MAINTAIN_TOP (BYTE_CODE_SAFE || BYTE_MARK_STACK)
 242 \f
 243 /* Structure describing a value stack used during byte-code execution
 244    in Fbyte_code.  */
 245
 246 struct byte_stack
 247 {
 248   /* Program counter.  This points into the byte_string below
 249      and is relocated when that string is relocated.  */
 250   const unsigned char *pc;
 251
 252   /* Top and bottom of stack.  The bottom points to an area of memory
 253      allocated with alloca in Fbyte_code.  */
 254 #if BYTE_MAINTAIN_TOP
 255   Lisp_Object *top, *bottom;
 256 #endif
 257
 258   /* The string containing the byte-code, and its current address.
 259      Storing this here protects it from GC because mark_byte_stack
 260      marks it.  */
 261   Lisp_Object byte_string;
 262   const unsigned char *byte_string_start;
 263
 264   /* The vector of constants used during byte-code execution.  Storing
 265      this here protects it from GC because mark_byte_stack marks it.  */
 266   Lisp_Object constants;
 267
 268   /* Next entry in byte_stack_list.  */
 269   struct byte_stack *next;
 270 };
 271
 272 /* A list of currently active byte-code execution value stacks.
 273    Fbyte_code adds an entry to the head of this list before it starts
 274    processing byte-code, and it removed the entry again when it is
 275    done.  Signalling an error truncates the list analoguous to
 276    gcprolist.  */
 277
 278 struct byte_stack *byte_stack_list;
 279
 280 \f
 281 /* Mark objects on byte_stack_list.  Called during GC.  */
 282
 283 #if BYTE_MARK_STACK
 284 void
 285 mark_byte_stack (void)
 286 {
 287   struct byte_stack *stack;
 288   Lisp_Object *obj;
 289
 290   for (stack = byte_stack_list; stack; stack = stack->next)
 291     {
 292       /* If STACK->top is null here, this means there's an opcode in
 293          Fbyte_code that wasn't expected to GC, but did.  To find out
 294          which opcode this is, record the value of `stack', and walk
 295          up the stack in a debugger, stopping in frames of Fbyte_code.
 296          The culprit is found in the frame of Fbyte_code where the
 297          address of its local variable `stack' is equal to the
 298          recorded value of `stack' here.  */
 299       eassert (stack->top);
 300
 301       for (obj = stack->bottom; obj <= stack->top; ++obj)
 302         mark_object (*obj);
 303
 304       mark_object (stack->byte_string);
 305       mark_object (stack->constants);
 306     }
 307 }
 308 #endif
 309
 310 /* Unmark objects in the stacks on byte_stack_list.  Relocate program
 311    counters.  Called when GC has completed.  */
 312
 313 void
 314 unmark_byte_stack (void)
 315 {
 316   struct byte_stack *stack;
 317
 318   for (stack = byte_stack_list; stack; stack = stack->next)
 319     {
 320       if (stack->byte_string_start != SDATA (stack->byte_string))
 321         {
 322           int offset = stack->pc - stack->byte_string_start;
 323           stack->byte_string_start = SDATA (stack->byte_string);
 324           stack->pc = stack->byte_string_start + offset;
 325         }
 326     }
 327 }
 328
 329 \f
 330 /* Fetch the next byte from the bytecode stream */
 331
 332 #define FETCH *stack.pc++
 333
 334 /* Fetch two bytes from the bytecode stream and make a 16-bit number
 335    out of them */
 336
 337 #define FETCH2 (op = FETCH, op + (FETCH << 8))
 338
 339 /* Push x onto the execution stack.  This used to be #define PUSH(x)
 340    (*++stackp = (x)) This oddity is necessary because Alliant can't be
 341    bothered to compile the preincrement operator properly, as of 4/91.
 342    -JimB */
 343
 344 #define PUSH(x) (top++, *top = (x))
 345
 346 /* Pop a value off the execution stack.  */
 347
 348 #define POP (*top--)
 349
 350 /* Discard n values from the execution stack.  */
 351
 352 #define DISCARD(n) (top -= (n))
 353
 354 /* Get the value which is at the top of the execution stack, but don't
 355    pop it. */
 356
 357 #define TOP (*top)
 358
 359 /* Actions that must be performed before and after calling a function
 360    that might GC.  */
 361
 362 #if !BYTE_MAINTAIN_TOP
 363 #define BEFORE_POTENTIAL_GC()   ((void)0)
 364 #define AFTER_POTENTIAL_GC()    ((void)0)
 365 #else
 366 #define BEFORE_POTENTIAL_GC()   stack.top = top
 367 #define AFTER_POTENTIAL_GC()    stack.top = NULL
 368 #endif
 369
 370 /* Garbage collect if we have consed enough since the last time.
 371    We do this at every branch, to avoid loops that never GC.  */
 372
 373 #define MAYBE_GC()                                      \
 374  do {                                                   \
 375   if (consing_since_gc > gc_cons_threshold              \
 376       && consing_since_gc > gc_relative_threshold)      \
 377     {                                                   \
 378       BEFORE_POTENTIAL_GC ();                           \
 379       Fgarbage_collect ();                              \
 380       AFTER_POTENTIAL_GC ();                            \
 381     }                                                   \
 382  } while (0)
 383
 384 /* Check for jumping out of range.  */
 385
 386 #ifdef BYTE_CODE_SAFE
 387
 388 #define CHECK_RANGE(ARG) \
 389   if (ARG >= bytestr_length) abort ()
 390
 391 #else /* not BYTE_CODE_SAFE */
 392
 393 #define CHECK_RANGE(ARG)
 394
 395 #endif /* not BYTE_CODE_SAFE */
 396
 397 /* A version of the QUIT macro which makes sure that the stack top is
 398    set before signaling `quit'.  */
 399
 400 #define BYTE_CODE_QUIT                                  \
 401   do {                                                  \
 402     if (!NILP (Vquit_flag) && NILP (Vinhibit_quit))     \
 403       {                                                 \
 404         Lisp_Object flag = Vquit_flag;                  \
 405         Vquit_flag = Qnil;                              \
 406         BEFORE_POTENTIAL_GC ();                         \
 407         if (EQ (Vthrow_on_input, flag))                 \
 408           Fthrow (Vthrow_on_input, Qt);                 \
 409         Fsignal (Qquit, Qnil);                          \
 410         AFTER_POTENTIAL_GC ();                          \
 411       }                                                 \
 412     ELSE_PENDING_SIGNALS                                \
 413   } while (0)
 414
 415
 416 DEFUN ("byte-code", Fbyte_code, Sbyte_code, 3, 3, 0,
 417        doc: /* Function used internally in byte-compiled code.
 418 The first argument, BYTESTR, is a string of byte code;
 419 the second, VECTOR, a vector of constants;
 420 the third, MAXDEPTH, the maximum stack depth used in this function.
 421 If the third argument is incorrect, Emacs may crash.  */)
 422   (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth)
 423 {
 424   return exec_byte_code (bytestr, vector, maxdepth, Qnil, 0, NULL);
 425 }
 426
 427 /* Execute the byte-code in BYTESTR.  VECTOR is the constant vector, and
 428    MAXDEPTH is the maximum stack depth used (if MAXDEPTH is incorrect,
 429    emacs may crash!).  If ARGS_TEMPLATE is non-nil, it should be a lisp
 430    argument list (including &rest, &optional, etc.), and ARGS, of size
 431    NARGS, should be a vector of the actual arguments.  The arguments in
 432    ARGS are pushed on the stack according to ARGS_TEMPLATE before
 433    executing BYTESTR.  */
 434
 435 Lisp_Object
 436 exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
 437                 Lisp_Object args_template, int nargs, Lisp_Object *args)
 438 {
 439   int count = SPECPDL_INDEX ();
 440 #ifdef BYTE_CODE_METER
 441   int this_op = 0;
 442   int prev_op;
 443 #endif
 444   int op;
 445   /* Lisp_Object v1, v2; */
 446   Lisp_Object *vectorp;
 447 #ifdef BYTE_CODE_SAFE
 448   int const_length = XVECTOR (vector)->size;
 449   Lisp_Object *stacke;
 450   int bytestr_length;
 451 #endif
 452   struct byte_stack stack;
 453   Lisp_Object *top;
 454   Lisp_Object result;
 455
 456 #if 0 /* CHECK_FRAME_FONT */
 457  {
 458    struct frame *f = SELECTED_FRAME ();
 459    if (FRAME_X_P (f)
 460        && FRAME_FONT (f)->direction != 0
 461        && FRAME_FONT (f)->direction != 1)
 462      abort ();
 463  }
 464 #endif
 465
 466   CHECK_STRING (bytestr);
 467   CHECK_VECTOR (vector);
 468   CHECK_NUMBER (maxdepth);
 469
 470   if (STRING_MULTIBYTE (bytestr))
 471     /* BYTESTR must have been produced by Emacs 20.2 or the earlier
 472        because they produced a raw 8-bit string for byte-code and now
 473        such a byte-code string is loaded as multibyte while raw 8-bit
 474        characters converted to multibyte form.  Thus, now we must
 475        convert them back to the originally intended unibyte form.  */
 476     bytestr = Fstring_as_unibyte (bytestr);
 477
 478 #ifdef BYTE_CODE_SAFE
 479   bytestr_length = SBYTES (bytestr);
 480 #endif
 481   vectorp = XVECTOR (vector)->contents;
 482
 483   stack.byte_string = bytestr;
 484   stack.pc = stack.byte_string_start = SDATA (bytestr);
 485   stack.constants = vector;
 486   top = (Lisp_Object *) alloca (XFASTINT (maxdepth)
 487                                          * sizeof (Lisp_Object));
 488 #if BYTE_MAINTAIN_TOP
 489   stack.bottom = top;
 490   stack.top = NULL;
 491 #endif
 492   top -= 1;
 493   stack.next = byte_stack_list;
 494   byte_stack_list = &stack;
 495
 496 #ifdef BYTE_CODE_SAFE
 497   stacke = stack.bottom - 1 + XFASTINT (maxdepth);
 498 #endif
 499
 500   if (INTEGERP (args_template))
 501     {
 502       int at = XINT (args_template);
 503       int rest = at & 128;
 504       int mandatory = at & 127;
 505       int nonrest = at >> 8;
 506       eassert (mandatory <= nonrest);
 507       if (nargs <= nonrest)
 508         {
 509           int i;
 510           for (i = 0 ; i < nargs; i++, args++)
 511             PUSH (*args);
 512           if (nargs < mandatory)
 513             /* Too few arguments.  */
 514             Fsignal (Qwrong_number_of_arguments,
 515                      Fcons (Fcons (make_number (mandatory),
 516                                    rest ? Qand_rest : make_number (nonrest)),
 517                             Fcons (make_number (nargs), Qnil)));
 518           else
 519             {
 520               for (; i < nonrest; i++)
 521                 PUSH (Qnil);
 522               if (rest)
 523                 PUSH (Qnil);
 524             }
 525         }
 526       else if (rest)
 527         {
 528           int i;
 529           for (i = 0 ; i < nonrest; i++, args++)
 530             PUSH (*args);
 531           PUSH (Flist (nargs - nonrest, args));
 532         }
 533       else
 534         /* Too many arguments.  */
 535         Fsignal (Qwrong_number_of_arguments,
 536                  Fcons (Fcons (make_number (mandatory),
 537                                make_number (nonrest)),
 538                         Fcons (make_number (nargs), Qnil)));
 539     }
 540   else if (! NILP (args_template))
 541     /* We should push some arguments on the stack.  */
 542     {
 543       error ("Unknown args template!");
 544     }
 545
 546   while (1)
 547     {
 548 #ifdef BYTE_CODE_SAFE
 549       if (top > stacke)
 550         abort ();
 551       else if (top < stack.bottom - 1)
 552         abort ();
 553 #endif
 554
 555 #ifdef BYTE_CODE_METER
 556       prev_op = this_op;
 557       this_op = op = FETCH;
 558       METER_CODE (prev_op, op);
 559 #else
 560       op = FETCH;
 561 #endif
 562
 563       switch (op)
 564         {
 565         case Bvarref + 7:
 566           op = FETCH2;
 567           goto varref;
 568
 569         case Bvarref:
 570         case Bvarref + 1:
 571         case Bvarref + 2:
 572         case Bvarref + 3:
 573         case Bvarref + 4:
 574         case Bvarref + 5:
 575           op = op - Bvarref;
 576           goto varref;
 577
 578         /* This seems to be the most frequently executed byte-code
 579            among the Bvarref's, so avoid a goto here.  */
 580         case Bvarref+6:
 581           op = FETCH;
 582         varref:
 583           {
 584             Lisp_Object v1, v2;
 585
 586             v1 = vectorp[op];
 587             if (SYMBOLP (v1))
 588               {
 589                 if (XSYMBOL (v1)->redirect != SYMBOL_PLAINVAL
 590                     || (v2 = SYMBOL_VAL (XSYMBOL (v1)),
 591                         EQ (v2, Qunbound)))
 592                   {
 593                     BEFORE_POTENTIAL_GC ();
 594                     v2 = Fsymbol_value (v1);
 595                     AFTER_POTENTIAL_GC ();
 596                   }
 597               }
 598             else
 599               {
 600                 BEFORE_POTENTIAL_GC ();
 601                 v2 = Fsymbol_value (v1);
 602                 AFTER_POTENTIAL_GC ();
 603               }
 604             PUSH (v2);
 605             break;
 606           }
 607
 608         case Bgotoifnil:
 609           {
 610             Lisp_Object v1;
 611             MAYBE_GC ();
 612             op = FETCH2;
 613             v1 = POP;
 614             if (NILP (v1))
 615               {
 616                 BYTE_CODE_QUIT;
 617                 CHECK_RANGE (op);
 618                 stack.pc = stack.byte_string_start + op;
 619               }
 620             break;
 621           }
 622
 623         case Bcar:
 624           {
 625             Lisp_Object v1;
 626             v1 = TOP;
 627             if (CONSP (v1))
 628               TOP = XCAR (v1);
 629             else if (NILP (v1))
 630               TOP = Qnil;
 631             else
 632               {
 633                 BEFORE_POTENTIAL_GC ();
 634                 wrong_type_argument (Qlistp, v1);
 635                 AFTER_POTENTIAL_GC ();
 636               }
 637             break;
 638           }
 639
 640         case Beq:
 641           {
 642             Lisp_Object v1;
 643             v1 = POP;
 644             TOP = EQ (v1, TOP) ? Qt : Qnil;
 645             break;
 646           }
 647
 648         case Bmemq:
 649           {
 650             Lisp_Object v1;
 651             BEFORE_POTENTIAL_GC ();
 652             v1 = POP;
 653             TOP = Fmemq (TOP, v1);
 654             AFTER_POTENTIAL_GC ();
 655             break;
 656           }
 657
 658         case Bcdr:
 659           {
 660             Lisp_Object v1;
 661             v1 = TOP;
 662             if (CONSP (v1))
 663               TOP = XCDR (v1);
 664             else if (NILP (v1))
 665               TOP = Qnil;
 666             else
 667               {
 668                 BEFORE_POTENTIAL_GC ();
 669                 wrong_type_argument (Qlistp, v1);
 670                 AFTER_POTENTIAL_GC ();
 671               }
 672             break;
 673             break;
 674           }
 675
 676         case Bvarset:
 677         case Bvarset+1:
 678         case Bvarset+2:
 679         case Bvarset+3:
 680         case Bvarset+4:
 681         case Bvarset+5:
 682           op -= Bvarset;
 683           goto varset;
 684
 685         case Bvarset+7:
 686           op = FETCH2;
 687           goto varset;
 688
 689         case Bvarset+6:
 690           op = FETCH;
 691         varset:
 692           {
 693             Lisp_Object sym, val;
 694
 695             sym = vectorp[op];
 696             val = TOP;
 697
 698             /* Inline the most common case.  */
 699             if (SYMBOLP (sym)
 700                 && !EQ (val, Qunbound)
 701                 && !XSYMBOL (sym)->redirect
 702                 && !SYMBOL_CONSTANT_P (sym))
 703               XSYMBOL (sym)->val.value = val;
 704             else
 705               {
 706                 BEFORE_POTENTIAL_GC ();
 707                 set_internal (sym, val, Qnil, 0);
 708                 AFTER_POTENTIAL_GC ();
 709               }
 710           }
 711           (void) POP;
 712           break;
 713
 714         case Bdup:
 715           {
 716             Lisp_Object v1;
 717             v1 = TOP;
 718             PUSH (v1);
 719             break;
 720           }
 721
 722         /* ------------------ */
 723
 724         case Bvarbind+6:
 725           op = FETCH;
 726           goto varbind;
 727
 728         case Bvarbind+7:
 729           op = FETCH2;
 730           goto varbind;
 731
 732         case Bvarbind:
 733         case Bvarbind+1:
 734         case Bvarbind+2:
 735         case Bvarbind+3:
 736         case Bvarbind+4:
 737         case Bvarbind+5:
 738           op -= Bvarbind;
 739         varbind:
 740           /* Specbind can signal and thus GC.  */
 741           BEFORE_POTENTIAL_GC ();
 742           specbind (vectorp[op], POP);
 743           AFTER_POTENTIAL_GC ();
 744           break;
 745
 746         case Bcall+6:
 747           op = FETCH;
 748           goto docall;
 749
 750         case Bcall+7:
 751           op = FETCH2;
 752           goto docall;
 753
 754         case Bcall:
 755         case Bcall+1:
 756         case Bcall+2:
 757         case Bcall+3:
 758         case Bcall+4:
 759         case Bcall+5:
 760           op -= Bcall;
 761         docall:
 762           {
 763             BEFORE_POTENTIAL_GC ();
 764             DISCARD (op);
 765 #ifdef BYTE_CODE_METER
 766             if (byte_metering_on && SYMBOLP (TOP))
 767               {
 768                 Lisp_Object v1, v2;
 769
 770                 v1 = TOP;
 771                 v2 = Fget (v1, Qbyte_code_meter);
 772                 if (INTEGERP (v2)
 773                     && XINT (v2) < MOST_POSITIVE_FIXNUM)
 774                   {
 775                     XSETINT (v2, XINT (v2) + 1);
 776                     Fput (v1, Qbyte_code_meter, v2);
 777                   }
 778               }
 779 #endif
 780             TOP = Ffuncall (op + 1, &TOP);
 781             AFTER_POTENTIAL_GC ();
 782             break;
 783           }
 784
 785         case Bunbind+6:
 786           op = FETCH;
 787           goto dounbind;
 788
 789         case Bunbind+7:
 790           op = FETCH2;
 791           goto dounbind;
 792
 793         case Bunbind:
 794         case Bunbind+1:
 795         case Bunbind+2:
 796         case Bunbind+3:
 797         case Bunbind+4:
 798         case Bunbind+5:
 799           op -= Bunbind;
 800         dounbind:
 801           BEFORE_POTENTIAL_GC ();
 802           unbind_to (SPECPDL_INDEX () - op, Qnil);
 803           AFTER_POTENTIAL_GC ();
 804           break;
 805
 806         case Bunbind_all:       /* Obsolete.  Never used.  */
 807           /* To unbind back to the beginning of this frame.  Not used yet,
 808              but will be needed for tail-recursion elimination.  */
 809           BEFORE_POTENTIAL_GC ();
 810           unbind_to (count, Qnil);
 811           AFTER_POTENTIAL_GC ();
 812           break;
 813
 814         case Bgoto:
 815           MAYBE_GC ();
 816           BYTE_CODE_QUIT;
 817           op = FETCH2;    /* pc = FETCH2 loses since FETCH2 contains pc++ */
 818           CHECK_RANGE (op);
 819           stack.pc = stack.byte_string_start + op;
 820           break;
 821
 822         case Bgotoifnonnil:
 823           {
 824             Lisp_Object v1;
 825             MAYBE_GC ();
 826             op = FETCH2;
 827             v1 = POP;
 828             if (!NILP (v1))
 829               {
 830                 BYTE_CODE_QUIT;
 831                 CHECK_RANGE (op);
 832                 stack.pc = stack.byte_string_start + op;
 833               }
 834             break;
 835           }
 836
 837         case Bgotoifnilelsepop:
 838           MAYBE_GC ();
 839           op = FETCH2;
 840           if (NILP (TOP))
 841             {
 842               BYTE_CODE_QUIT;
 843               CHECK_RANGE (op);
 844               stack.pc = stack.byte_string_start + op;
 845             }
 846           else DISCARD (1);
 847           break;
 848
 849         case Bgotoifnonnilelsepop:
 850           MAYBE_GC ();
 851           op = FETCH2;
 852           if (!NILP (TOP))
 853             {
 854               BYTE_CODE_QUIT;
 855               CHECK_RANGE (op);
 856               stack.pc = stack.byte_string_start + op;
 857             }
 858           else DISCARD (1);
 859           break;
 860
 861         case BRgoto:
 862           MAYBE_GC ();
 863           BYTE_CODE_QUIT;
 864           stack.pc += (int) *stack.pc - 127;
 865           break;
 866
 867         case BRgotoifnil:
 868           {
 869             Lisp_Object v1;
 870             MAYBE_GC ();
 871             v1 = POP;
 872             if (NILP (v1))
 873               {
 874                 BYTE_CODE_QUIT;
 875                 stack.pc += (int) *stack.pc - 128;
 876               }
 877             stack.pc++;
 878             break;
 879           }
 880
 881         case BRgotoifnonnil:
 882           {
 883             Lisp_Object v1;
 884             MAYBE_GC ();
 885             v1 = POP;
 886             if (!NILP (v1))
 887               {
 888                 BYTE_CODE_QUIT;
 889                 stack.pc += (int) *stack.pc - 128;
 890               }
 891             stack.pc++;
 892             break;
 893           }
 894
 895         case BRgotoifnilelsepop:
 896           MAYBE_GC ();
 897           op = *stack.pc++;
 898           if (NILP (TOP))
 899             {
 900               BYTE_CODE_QUIT;
 901               stack.pc += op - 128;
 902             }
 903           else DISCARD (1);
 904           break;
 905
 906         case BRgotoifnonnilelsepop:
 907           MAYBE_GC ();
 908           op = *stack.pc++;
 909           if (!NILP (TOP))
 910             {
 911               BYTE_CODE_QUIT;
 912               stack.pc += op - 128;
 913             }
 914           else DISCARD (1);
 915           break;
 916
 917         case Breturn:
 918           result = POP;
 919           goto exit;
 920
 921         case Bdiscard:
 922           DISCARD (1);
 923           break;
 924
 925         case Bconstant2:
 926           PUSH (vectorp[FETCH2]);
 927           break;
 928
 929         case Bsave_excursion:
 930           record_unwind_protect (save_excursion_restore,
 931                                  save_excursion_save ());
 932           break;
 933
 934         case Bsave_current_buffer: /* Obsolete since ??.  */
 935         case Bsave_current_buffer_1:
 936           record_unwind_protect (set_buffer_if_live, Fcurrent_buffer ());
 937           break;
 938
 939         case Bsave_window_excursion: /* Obsolete since 24.1.  */
 940           {
 941             register int count1 = SPECPDL_INDEX ();
 942             record_unwind_protect (Fset_window_configuration,
 943                                    Fcurrent_window_configuration (Qnil));
 944             BEFORE_POTENTIAL_GC ();
 945             TOP = Fprogn (TOP);
 946             unbind_to (count1, TOP);
 947             AFTER_POTENTIAL_GC ();
 948             break;
 949           }
 950
 951         case Bsave_restriction:
 952           record_unwind_protect (save_restriction_restore,
 953                                  save_restriction_save ());
 954           break;
 955
 956         case Bcatch:            /* FIXME: ill-suited for lexbind */
 957           {
 958             Lisp_Object v1;
 959             BEFORE_POTENTIAL_GC ();
 960             v1 = POP;
 961             TOP = internal_catch (TOP, eval_sub, v1);
 962             AFTER_POTENTIAL_GC ();
 963             break;
 964           }
 965
 966         case Bunwind_protect:   /* FIXME: avoid closure for lexbind */
 967           record_unwind_protect (Fprogn, POP);
 968           break;
 969
 970         case Bcondition_case:   /* FIXME: ill-suited for lexbind */
 971           {
 972             Lisp_Object handlers, body;
 973             handlers = POP;
 974             body = POP;
 975             BEFORE_POTENTIAL_GC ();
 976             TOP = internal_lisp_condition_case (TOP, body, handlers);
 977             AFTER_POTENTIAL_GC ();
 978             break;
 979           }
 980
 981         case Btemp_output_buffer_setup: /* Obsolete since 24.1.  */
 982           BEFORE_POTENTIAL_GC ();
 983           CHECK_STRING (TOP);
 984           temp_output_buffer_setup (SSDATA (TOP));
 985           AFTER_POTENTIAL_GC ();
 986           TOP = Vstandard_output;
 987           break;
 988
 989         case Btemp_output_buffer_show: /* Obsolete since 24.1.  */
 990           {
 991             Lisp_Object v1;
 992             BEFORE_POTENTIAL_GC ();
 993             v1 = POP;
 994             temp_output_buffer_show (TOP);
 995             TOP = v1;
 996             /* pop binding of standard-output */
 997             unbind_to (SPECPDL_INDEX () - 1, Qnil);
 998             AFTER_POTENTIAL_GC ();
 999             break;
1000           }
1001
1002         case Bnth:
1003           {
1004             Lisp_Object v1, v2;
1005             BEFORE_POTENTIAL_GC ();
1006             v1 = POP;
1007             v2 = TOP;
1008             CHECK_NUMBER (v2);
1009             op = XINT (v2);
1010             immediate_quit = 1;
1011             while (--op >= 0 && CONSP (v1))
1012               v1 = XCDR (v1);
1013             immediate_quit = 0;
1014             TOP = CAR (v1);
1015             AFTER_POTENTIAL_GC ();
1016             break;
1017           }
1018
1019         case Bsymbolp:
1020           TOP = SYMBOLP (TOP) ? Qt : Qnil;
1021           break;
1022
1023         case Bconsp:
1024           TOP = CONSP (TOP) ? Qt : Qnil;
1025           break;
1026
1027         case Bstringp:
1028           TOP = STRINGP (TOP) ? Qt : Qnil;
1029           break;
1030
1031         case Blistp:
1032           TOP = CONSP (TOP) || NILP (TOP) ? Qt : Qnil;
1033           break;
1034
1035         case Bnot:
1036           TOP = NILP (TOP) ? Qt : Qnil;
1037           break;
1038
1039         case Bcons:
1040           {
1041             Lisp_Object v1;
1042             v1 = POP;
1043             TOP = Fcons (TOP, v1);
1044             break;
1045           }
1046
1047         case Blist1:
1048           TOP = Fcons (TOP, Qnil);
1049           break;
1050
1051         case Blist2:
1052           {
1053             Lisp_Object v1;
1054             v1 = POP;
1055             TOP = Fcons (TOP, Fcons (v1, Qnil));
1056             break;
1057           }
1058
1059         case Blist3:
1060           DISCARD (2);
1061           TOP = Flist (3, &TOP);
1062           break;
1063
1064         case Blist4:
1065           DISCARD (3);
1066           TOP = Flist (4, &TOP);
1067           break;
1068
1069         case BlistN:
1070           op = FETCH;
1071           DISCARD (op - 1);
1072           TOP = Flist (op, &TOP);
1073           break;
1074
1075         case Blength:
1076           BEFORE_POTENTIAL_GC ();
1077           TOP = Flength (TOP);
1078           AFTER_POTENTIAL_GC ();
1079           break;
1080
1081         case Baref:
1082           {
1083             Lisp_Object v1;
1084             BEFORE_POTENTIAL_GC ();
1085             v1 = POP;
1086             TOP = Faref (TOP, v1);
1087             AFTER_POTENTIAL_GC ();
1088             break;
1089           }
1090
1091         case Baset:
1092           {
1093             Lisp_Object v1, v2;
1094             BEFORE_POTENTIAL_GC ();
1095             v2 = POP; v1 = POP;
1096             TOP = Faset (TOP, v1, v2);
1097             AFTER_POTENTIAL_GC ();
1098             break;
1099           }
1100
1101         case Bsymbol_value:
1102           BEFORE_POTENTIAL_GC ();
1103           TOP = Fsymbol_value (TOP);
1104           AFTER_POTENTIAL_GC ();
1105           break;
1106
1107         case Bsymbol_function:
1108           BEFORE_POTENTIAL_GC ();
1109           TOP = Fsymbol_function (TOP);
1110           AFTER_POTENTIAL_GC ();
1111           break;
1112
1113         case Bset:
1114           {
1115             Lisp_Object v1;
1116             BEFORE_POTENTIAL_GC ();
1117             v1 = POP;
1118             TOP = Fset (TOP, v1);
1119             AFTER_POTENTIAL_GC ();
1120             break;
1121           }
1122
1123         case Bfset:
1124           {
1125             Lisp_Object v1;
1126             BEFORE_POTENTIAL_GC ();
1127             v1 = POP;
1128             TOP = Ffset (TOP, v1);
1129             AFTER_POTENTIAL_GC ();
1130             break;
1131           }
1132
1133         case Bget:
1134           {
1135             Lisp_Object v1;
1136             BEFORE_POTENTIAL_GC ();
1137             v1 = POP;
1138             TOP = Fget (TOP, v1);
1139             AFTER_POTENTIAL_GC ();
1140             break;
1141           }
1142
1143         case Bsubstring:
1144           {
1145             Lisp_Object v1, v2;
1146             BEFORE_POTENTIAL_GC ();
1147             v2 = POP; v1 = POP;
1148             TOP = Fsubstring (TOP, v1, v2);
1149             AFTER_POTENTIAL_GC ();
1150             break;
1151           }
1152
1153         case Bconcat2:
1154           BEFORE_POTENTIAL_GC ();
1155           DISCARD (1);
1156           TOP = Fconcat (2, &TOP);
1157           AFTER_POTENTIAL_GC ();
1158           break;
1159
1160         case Bconcat3:
1161           BEFORE_POTENTIAL_GC ();
1162           DISCARD (2);
1163           TOP = Fconcat (3, &TOP);
1164           AFTER_POTENTIAL_GC ();
1165           break;
1166
1167         case Bconcat4:
1168           BEFORE_POTENTIAL_GC ();
1169           DISCARD (3);
1170           TOP = Fconcat (4, &TOP);
1171           AFTER_POTENTIAL_GC ();
1172           break;
1173
1174         case BconcatN:
1175           op = FETCH;
1176           BEFORE_POTENTIAL_GC ();
1177           DISCARD (op - 1);
1178           TOP = Fconcat (op, &TOP);
1179           AFTER_POTENTIAL_GC ();
1180           break;
1181
1182         case Bsub1:
1183           {
1184             Lisp_Object v1;
1185             v1 = TOP;
1186             if (INTEGERP (v1))
1187               {
1188                 XSETINT (v1, XINT (v1) - 1);
1189                 TOP = v1;
1190               }
1191             else
1192               {
1193                 BEFORE_POTENTIAL_GC ();
1194                 TOP = Fsub1 (v1);
1195                 AFTER_POTENTIAL_GC ();
1196               }
1197             break;
1198           }
1199
1200         case Badd1:
1201           {
1202             Lisp_Object v1;
1203             v1 = TOP;
1204             if (INTEGERP (v1))
1205               {
1206                 XSETINT (v1, XINT (v1) + 1);
1207                 TOP = v1;
1208               }
1209             else
1210               {
1211                 BEFORE_POTENTIAL_GC ();
1212                 TOP = Fadd1 (v1);
1213                 AFTER_POTENTIAL_GC ();
1214               }
1215             break;
1216           }
1217
1218         case Beqlsign:
1219           {
1220             Lisp_Object v1, v2;
1221             BEFORE_POTENTIAL_GC ();
1222             v2 = POP; v1 = TOP;
1223             CHECK_NUMBER_OR_FLOAT_COERCE_MARKER (v1);
1224             CHECK_NUMBER_OR_FLOAT_COERCE_MARKER (v2);
1225             AFTER_POTENTIAL_GC ();
1226             if (FLOATP (v1) || FLOATP (v2))
1227               {
1228                 double f1, f2;
1229
1230                 f1 = (FLOATP (v1) ? XFLOAT_DATA (v1) : XINT (v1));
1231                 f2 = (FLOATP (v2) ? XFLOAT_DATA (v2) : XINT (v2));
1232                 TOP = (f1 == f2 ? Qt : Qnil);
1233               }
1234             else
1235               TOP = (XINT (v1) == XINT (v2) ? Qt : Qnil);
1236             break;
1237           }
1238
1239         case Bgtr:
1240           {
1241             Lisp_Object v1;
1242             BEFORE_POTENTIAL_GC ();
1243             v1 = POP;
1244             TOP = Fgtr (TOP, v1);
1245             AFTER_POTENTIAL_GC ();
1246             break;
1247           }
1248
1249         case Blss:
1250           {
1251             Lisp_Object v1;
1252             BEFORE_POTENTIAL_GC ();
1253             v1 = POP;
1254             TOP = Flss (TOP, v1);
1255             AFTER_POTENTIAL_GC ();
1256             break;
1257           }
1258
1259         case Bleq:
1260           {
1261             Lisp_Object v1;
1262             BEFORE_POTENTIAL_GC ();
1263             v1 = POP;
1264             TOP = Fleq (TOP, v1);
1265             AFTER_POTENTIAL_GC ();
1266             break;
1267           }
1268
1269         case Bgeq:
1270           {
1271             Lisp_Object v1;
1272             BEFORE_POTENTIAL_GC ();
1273             v1 = POP;
1274             TOP = Fgeq (TOP, v1);
1275             AFTER_POTENTIAL_GC ();
1276             break;
1277           }
1278
1279         case Bdiff:
1280           BEFORE_POTENTIAL_GC ();
1281           DISCARD (1);
1282           TOP = Fminus (2, &TOP);
1283           AFTER_POTENTIAL_GC ();
1284           break;
1285
1286         case Bnegate:
1287           {
1288             Lisp_Object v1;
1289             v1 = TOP;
1290             if (INTEGERP (v1))
1291               {
1292                 XSETINT (v1, - XINT (v1));
1293                 TOP = v1;
1294               }
1295             else
1296               {
1297                 BEFORE_POTENTIAL_GC ();
1298                 TOP = Fminus (1, &TOP);
1299                 AFTER_POTENTIAL_GC ();
1300               }
1301             break;
1302           }
1303
1304         case Bplus:
1305           BEFORE_POTENTIAL_GC ();
1306           DISCARD (1);
1307           TOP = Fplus (2, &TOP);
1308           AFTER_POTENTIAL_GC ();
1309           break;
1310
1311         case Bmax:
1312           BEFORE_POTENTIAL_GC ();
1313           DISCARD (1);
1314           TOP = Fmax (2, &TOP);
1315           AFTER_POTENTIAL_GC ();
1316           break;
1317
1318         case Bmin:
1319           BEFORE_POTENTIAL_GC ();
1320           DISCARD (1);
1321           TOP = Fmin (2, &TOP);
1322           AFTER_POTENTIAL_GC ();
1323           break;
1324
1325         case Bmult:
1326           BEFORE_POTENTIAL_GC ();
1327           DISCARD (1);
1328           TOP = Ftimes (2, &TOP);
1329           AFTER_POTENTIAL_GC ();
1330           break;
1331
1332         case Bquo:
1333           BEFORE_POTENTIAL_GC ();
1334           DISCARD (1);
1335           TOP = Fquo (2, &TOP);
1336           AFTER_POTENTIAL_GC ();
1337           break;
1338
1339         case Brem:
1340           {
1341             Lisp_Object v1;
1342             BEFORE_POTENTIAL_GC ();
1343             v1 = POP;
1344             TOP = Frem (TOP, v1);
1345             AFTER_POTENTIAL_GC ();
1346             break;
1347           }
1348
1349         case Bpoint:
1350           {
1351             Lisp_Object v1;
1352             XSETFASTINT (v1, PT);
1353             PUSH (v1);
1354             break;
1355           }
1356
1357         case Bgoto_char:
1358           BEFORE_POTENTIAL_GC ();
1359           TOP = Fgoto_char (TOP);
1360           AFTER_POTENTIAL_GC ();
1361           break;
1362
1363         case Binsert:
1364           BEFORE_POTENTIAL_GC ();
1365           TOP = Finsert (1, &TOP);
1366           AFTER_POTENTIAL_GC ();
1367           break;
1368
1369         case BinsertN:
1370           op = FETCH;
1371           BEFORE_POTENTIAL_GC ();
1372           DISCARD (op - 1);
1373           TOP = Finsert (op, &TOP);
1374           AFTER_POTENTIAL_GC ();
1375           break;
1376
1377         case Bpoint_max:
1378           {
1379             Lisp_Object v1;
1380             XSETFASTINT (v1, ZV);
1381             PUSH (v1);
1382             break;
1383           }
1384
1385         case Bpoint_min:
1386           {
1387             Lisp_Object v1;
1388             XSETFASTINT (v1, BEGV);
1389             PUSH (v1);
1390             break;
1391           }
1392
1393         case Bchar_after:
1394           BEFORE_POTENTIAL_GC ();
1395           TOP = Fchar_after (TOP);
1396           AFTER_POTENTIAL_GC ();
1397           break;
1398
1399         case Bfollowing_char:
1400           {
1401             Lisp_Object v1;
1402             BEFORE_POTENTIAL_GC ();
1403             v1 = Ffollowing_char ();
1404             AFTER_POTENTIAL_GC ();
1405             PUSH (v1);
1406             break;
1407           }
1408
1409         case Bpreceding_char:
1410           {
1411             Lisp_Object v1;
1412             BEFORE_POTENTIAL_GC ();
1413             v1 = Fprevious_char ();
1414             AFTER_POTENTIAL_GC ();
1415             PUSH (v1);
1416             break;
1417           }
1418
1419         case Bcurrent_column:
1420           {
1421             Lisp_Object v1;
1422             BEFORE_POTENTIAL_GC ();
1423             XSETFASTINT (v1, current_column ());
1424             AFTER_POTENTIAL_GC ();
1425             PUSH (v1);
1426             break;
1427           }
1428
1429         case Bindent_to:
1430           BEFORE_POTENTIAL_GC ();
1431           TOP = Findent_to (TOP, Qnil);
1432           AFTER_POTENTIAL_GC ();
1433           break;
1434
1435         case Beolp:
1436           PUSH (Feolp ());
1437           break;
1438
1439         case Beobp:
1440           PUSH (Feobp ());
1441           break;
1442
1443         case Bbolp:
1444           PUSH (Fbolp ());
1445           break;
1446
1447         case Bbobp:
1448           PUSH (Fbobp ());
1449           break;
1450
1451         case Bcurrent_buffer:
1452           PUSH (Fcurrent_buffer ());
1453           break;
1454
1455         case Bset_buffer:
1456           BEFORE_POTENTIAL_GC ();
1457           TOP = Fset_buffer (TOP);
1458           AFTER_POTENTIAL_GC ();
1459           break;
1460
1461         case Binteractive_p:    /* Obsolete since 24.1.  */
1462           PUSH (Finteractive_p ());
1463           break;
1464
1465         case Bforward_char:
1466           BEFORE_POTENTIAL_GC ();
1467           TOP = Fforward_char (TOP);
1468           AFTER_POTENTIAL_GC ();
1469           break;
1470
1471         case Bforward_word:
1472           BEFORE_POTENTIAL_GC ();
1473           TOP = Fforward_word (TOP);
1474           AFTER_POTENTIAL_GC ();
1475           break;
1476
1477         case Bskip_chars_forward:
1478           {
1479             Lisp_Object v1;
1480             BEFORE_POTENTIAL_GC ();
1481             v1 = POP;
1482             TOP = Fskip_chars_forward (TOP, v1);
1483             AFTER_POTENTIAL_GC ();
1484             break;
1485           }
1486
1487         case Bskip_chars_backward:
1488           {
1489             Lisp_Object v1;
1490             BEFORE_POTENTIAL_GC ();
1491             v1 = POP;
1492             TOP = Fskip_chars_backward (TOP, v1);
1493             AFTER_POTENTIAL_GC ();
1494             break;
1495           }
1496
1497         case Bforward_line:
1498           BEFORE_POTENTIAL_GC ();
1499           TOP = Fforward_line (TOP);
1500           AFTER_POTENTIAL_GC ();
1501           break;
1502
1503         case Bchar_syntax:
1504           {
1505             int c;
1506
1507             BEFORE_POTENTIAL_GC ();
1508             CHECK_CHARACTER (TOP);
1509             AFTER_POTENTIAL_GC ();
1510             c = XFASTINT (TOP);
1511             if (NILP (BVAR (current_buffer, enable_multibyte_characters)))
1512               MAKE_CHAR_MULTIBYTE (c);
1513             XSETFASTINT (TOP, syntax_code_spec[(int) SYNTAX (c)]);
1514           }
1515           break;
1516
1517         case Bbuffer_substring:
1518           {
1519             Lisp_Object v1;
1520             BEFORE_POTENTIAL_GC ();
1521             v1 = POP;
1522             TOP = Fbuffer_substring (TOP, v1);
1523             AFTER_POTENTIAL_GC ();
1524             break;
1525           }
1526
1527         case Bdelete_region:
1528           {
1529             Lisp_Object v1;
1530             BEFORE_POTENTIAL_GC ();
1531             v1 = POP;
1532             TOP = Fdelete_region (TOP, v1);
1533             AFTER_POTENTIAL_GC ();
1534             break;
1535           }
1536
1537         case Bnarrow_to_region:
1538           {
1539             Lisp_Object v1;
1540             BEFORE_POTENTIAL_GC ();
1541             v1 = POP;
1542             TOP = Fnarrow_to_region (TOP, v1);
1543             AFTER_POTENTIAL_GC ();
1544             break;
1545           }
1546
1547         case Bwiden:
1548           BEFORE_POTENTIAL_GC ();
1549           PUSH (Fwiden ());
1550           AFTER_POTENTIAL_GC ();
1551           break;
1552
1553         case Bend_of_line:
1554           BEFORE_POTENTIAL_GC ();
1555           TOP = Fend_of_line (TOP);
1556           AFTER_POTENTIAL_GC ();
1557           break;
1558
1559         case Bset_marker:
1560           {
1561             Lisp_Object v1, v2;
1562             BEFORE_POTENTIAL_GC ();
1563             v1 = POP;
1564             v2 = POP;
1565             TOP = Fset_marker (TOP, v2, v1);
1566             AFTER_POTENTIAL_GC ();
1567             break;
1568           }
1569
1570         case Bmatch_beginning:
1571           BEFORE_POTENTIAL_GC ();
1572           TOP = Fmatch_beginning (TOP);
1573           AFTER_POTENTIAL_GC ();
1574           break;
1575
1576         case Bmatch_end:
1577           BEFORE_POTENTIAL_GC ();
1578           TOP = Fmatch_end (TOP);
1579           AFTER_POTENTIAL_GC ();
1580           break;
1581
1582         case Bupcase:
1583           BEFORE_POTENTIAL_GC ();
1584           TOP = Fupcase (TOP);
1585           AFTER_POTENTIAL_GC ();
1586           break;
1587
1588         case Bdowncase:
1589           BEFORE_POTENTIAL_GC ();
1590           TOP = Fdowncase (TOP);
1591           AFTER_POTENTIAL_GC ();
1592         break;
1593
1594         case Bstringeqlsign:
1595           {
1596             Lisp_Object v1;
1597             BEFORE_POTENTIAL_GC ();
1598             v1 = POP;
1599             TOP = Fstring_equal (TOP, v1);
1600             AFTER_POTENTIAL_GC ();
1601             break;
1602           }
1603
1604         case Bstringlss:
1605           {
1606             Lisp_Object v1;
1607             BEFORE_POTENTIAL_GC ();
1608             v1 = POP;
1609             TOP = Fstring_lessp (TOP, v1);
1610             AFTER_POTENTIAL_GC ();
1611             break;
1612           }
1613
1614         case Bequal:
1615           {
1616             Lisp_Object v1;
1617             v1 = POP;
1618             TOP = Fequal (TOP, v1);
1619             break;
1620           }
1621
1622         case Bnthcdr:
1623           {
1624             Lisp_Object v1;
1625             BEFORE_POTENTIAL_GC ();
1626             v1 = POP;
1627             TOP = Fnthcdr (TOP, v1);
1628             AFTER_POTENTIAL_GC ();
1629             break;
1630           }
1631
1632         case Belt:
1633           {
1634             Lisp_Object v1, v2;
1635             if (CONSP (TOP))
1636               {
1637                 /* Exchange args and then do nth.  */
1638                 BEFORE_POTENTIAL_GC ();
1639                 v2 = POP;
1640                 v1 = TOP;
1641                 CHECK_NUMBER (v2);
1642                 AFTER_POTENTIAL_GC ();
1643                 op = XINT (v2);
1644                 immediate_quit = 1;
1645                 while (--op >= 0 && CONSP (v1))
1646                   v1 = XCDR (v1);
1647                 immediate_quit = 0;
1648                 TOP = CAR (v1);
1649               }
1650             else
1651               {
1652                 BEFORE_POTENTIAL_GC ();
1653                 v1 = POP;
1654                 TOP = Felt (TOP, v1);
1655                 AFTER_POTENTIAL_GC ();
1656               }
1657             break;
1658           }
1659
1660         case Bmember:
1661           {
1662             Lisp_Object v1;
1663             BEFORE_POTENTIAL_GC ();
1664             v1 = POP;
1665             TOP = Fmember (TOP, v1);
1666             AFTER_POTENTIAL_GC ();
1667             break;
1668           }
1669
1670         case Bassq:
1671           {
1672             Lisp_Object v1;
1673             BEFORE_POTENTIAL_GC ();
1674             v1 = POP;
1675             TOP = Fassq (TOP, v1);
1676             AFTER_POTENTIAL_GC ();
1677             break;
1678           }
1679
1680         case Bnreverse:
1681           BEFORE_POTENTIAL_GC ();
1682           TOP = Fnreverse (TOP);
1683           AFTER_POTENTIAL_GC ();
1684           break;
1685
1686         case Bsetcar:
1687           {
1688             Lisp_Object v1;
1689             BEFORE_POTENTIAL_GC ();
1690             v1 = POP;
1691             TOP = Fsetcar (TOP, v1);
1692             AFTER_POTENTIAL_GC ();
1693             break;
1694           }
1695
1696         case Bsetcdr:
1697           {
1698             Lisp_Object v1;
1699             BEFORE_POTENTIAL_GC ();
1700             v1 = POP;
1701             TOP = Fsetcdr (TOP, v1);
1702             AFTER_POTENTIAL_GC ();
1703             break;
1704           }
1705
1706         case Bcar_safe:
1707           {
1708             Lisp_Object v1;
1709             v1 = TOP;
1710             TOP = CAR_SAFE (v1);
1711             break;
1712           }
1713
1714         case Bcdr_safe:
1715           {
1716             Lisp_Object v1;
1717             v1 = TOP;
1718             TOP = CDR_SAFE (v1);
1719             break;
1720           }
1721
1722         case Bnconc:
1723           BEFORE_POTENTIAL_GC ();
1724           DISCARD (1);
1725           TOP = Fnconc (2, &TOP);
1726           AFTER_POTENTIAL_GC ();
1727           break;
1728
1729         case Bnumberp:
1730           TOP = (NUMBERP (TOP) ? Qt : Qnil);
1731           break;
1732
1733         case Bintegerp:
1734           TOP = INTEGERP (TOP) ? Qt : Qnil;
1735           break;
1736
1737 #ifdef BYTE_CODE_SAFE
1738         case Bset_mark:
1739           BEFORE_POTENTIAL_GC ();
1740           error ("set-mark is an obsolete bytecode");
1741           AFTER_POTENTIAL_GC ();
1742           break;
1743         case Bscan_buffer:
1744           BEFORE_POTENTIAL_GC ();
1745           error ("scan-buffer is an obsolete bytecode");
1746           AFTER_POTENTIAL_GC ();
1747           break;
1748 #endif
1749
1750         case 0:
1751           /* Actually this is Bstack_ref with offset 0, but we use Bdup
1752              for that instead.  */
1753           /* case Bstack_ref: */
1754           abort ();
1755
1756           /* Handy byte-codes for lexical binding.  */
1757         case Bstack_ref+1:
1758         case Bstack_ref+2:
1759         case Bstack_ref+3:
1760         case Bstack_ref+4:
1761         case Bstack_ref+5:
1762           {
1763             Lisp_Object *ptr = top - (op - Bstack_ref);
1764             PUSH (*ptr);
1765             break;
1766           }
1767         case Bstack_ref+6:
1768           {
1769             Lisp_Object *ptr = top - (FETCH);
1770             PUSH (*ptr);
1771             break;
1772           }
1773         case Bstack_ref+7:
1774           {
1775             Lisp_Object *ptr = top - (FETCH2);
1776             PUSH (*ptr);
1777             break;
1778           }
1779           /* stack-set-0 = discard; stack-set-1 = discard-1-preserve-tos.  */
1780         case Bstack_set:
1781           {
1782             Lisp_Object *ptr = top - (FETCH);
1783             *ptr = POP;
1784             break;
1785           }
1786         case Bstack_set2:
1787           {
1788             Lisp_Object *ptr = top - (FETCH2);
1789             *ptr = POP;
1790             break;
1791           }
1792         case BdiscardN:
1793           op = FETCH;
1794           if (op & 0x80)
1795             {
1796               op &= 0x7F;
1797               top[-op] = TOP;
1798             }
1799           DISCARD (op);
1800           break;
1801
1802         case 255:
1803         default:
1804 #ifdef BYTE_CODE_SAFE
1805           if (op < Bconstant)
1806             {
1807               abort ();
1808             }
1809           if ((op -= Bconstant) >= const_length)
1810             {
1811               abort ();
1812             }
1813           PUSH (vectorp[op]);
1814 #else
1815           PUSH (vectorp[op - Bconstant]);
1816 #endif
1817         }
1818     }
1819
1820  exit:
1821
1822   byte_stack_list = byte_stack_list->next;
1823
1824   /* Binds and unbinds are supposed to be compiled balanced.  */
1825   if (SPECPDL_INDEX () != count)
1826 #ifdef BYTE_CODE_SAFE
1827     error ("binding stack not balanced (serious byte compiler bug)");
1828 #else
1829     abort ();
1830 #endif
1831
1832   return result;
1833 }
1834
1835 void
1836 syms_of_bytecode (void)
1837 {
1838   Qbytecode = intern_c_string ("byte-code");
1839   staticpro (&Qbytecode);
1840
1841   defsubr (&Sbyte_code);
1842
1843 #ifdef BYTE_CODE_METER
1844
1845   DEFVAR_LISP ("byte-code-meter", Vbyte_code_meter,
1846                doc: /* A vector of vectors which holds a histogram of byte-code usage.
1847 \(aref (aref byte-code-meter 0) CODE) indicates how many times the byte
1848 opcode CODE has been executed.
1849 \(aref (aref byte-code-meter CODE1) CODE2), where CODE1 is not 0,
1850 indicates how many times the byte opcodes CODE1 and CODE2 have been
1851 executed in succession.  */);
1852
1853   DEFVAR_BOOL ("byte-metering-on", byte_metering_on,
1854                doc: /* If non-nil, keep profiling information on byte code usage.
1855 The variable byte-code-meter indicates how often each byte opcode is used.
1856 If a symbol has a property named `byte-code-meter' whose value is an
1857 integer, it is incremented each time that symbol's function is called.  */);
1858
1859   byte_metering_on = 0;
1860   Vbyte_code_meter = Fmake_vector (make_number (256), make_number (0));
1861   Qbyte_code_meter = intern_c_string ("byte-code-meter");
1862   staticpro (&Qbyte_code_meter);
1863   {
1864     int i = 256;
1865     while (i--)
1866       XVECTOR (Vbyte_code_meter)->contents[i] =
1867         Fmake_vector (make_number (256), make_number (0));
1868   }
1869 #endif
1870 }