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