libguile/tags.h

   1 /* classes: h_files */
   2
   3 #ifndef TAGSH
   4 #define TAGSH
   5 /* Copyright (C) 1995, 96, 97, 98, 99, 2000 Free Software Foundation, Inc.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2, or (at your option)
  10  * any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this software; see the file COPYING.  If not, write to
  19  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  20  * Boston, MA 02111-1307 USA
  21  *
  22  * As a special exception, the Free Software Foundation gives permission
  23  * for additional uses of the text contained in its release of GUILE.
  24  *
  25  * The exception is that, if you link the GUILE library with other files
  26  * to produce an executable, this does not by itself cause the
  27  * resulting executable to be covered by the GNU General Public License.
  28  * Your use of that executable is in no way restricted on account of
  29  * linking the GUILE library code into it.
  30  *
  31  * This exception does not however invalidate any other reasons why
  32  * the executable file might be covered by the GNU General Public License.
  33  *
  34  * This exception applies only to the code released by the
  35  * Free Software Foundation under the name GUILE.  If you copy
  36  * code from other Free Software Foundation releases into a copy of
  37  * GUILE, as the General Public License permits, the exception does
  38  * not apply to the code that you add in this way.  To avoid misleading
  39  * anyone as to the status of such modified files, you must delete
  40  * this exception notice from them.
  41  *
  42  * If you write modifications of your own for GUILE, it is your choice
  43  * whether to permit this exception to apply to your modifications.
  44  * If you do not wish that, delete this exception notice.  */
  45
  46 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
  47    gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
  48
  49 \f
  50
  51 /** This file defines the format of SCM values and cons pairs.
  52  ** It is here that tag bits are assigned for various purposes.
  53  **/
  54
  55 \f
  56
  57
  58 /* In the beginning was the Word:
  59  */
  60 typedef long scm_bits_t;
  61 /*
  62   But as external interface, we use void*, which will be checked more strictly for
  63   dubious conversions.
  64  */
  65 #define SCM_VOIDP_TEST
  66 #ifndef SCM_VOIDP_TEST
  67 typedef scm_bits_t  SCM;
  68 #define SCM_UNPACK(x) (x)
  69 #define SCM_PACK(x) (x)
  70 #else
  71 typedef void * SCM;
  72 #define SCM_UNPACK(x) ((scm_bits_t) (x))
  73 #define SCM_PACK(x) ((SCM) (x))
  74 #endif
  75
  76 /* SCM_UNPACK_CAR is a convenience for treating the CAR of X as a word */
  77 #define SCM_UNPACK_CAR(x) SCM_UNPACK (SCM_CAR (x))
  78
  79
  80 /* Cray machines have pointers that are incremented once for each word,
  81  * rather than each byte, the 3 most significant bits encode the byte
  82  * within the word.  The following macros deal with this by storing the
  83  * native Cray pointers like the ones that looks like scm expects.  This
  84  * is done for any pointers that might appear in the car of a scm_cell, pointers
  85  * to scm_vector elts, functions, &c are not munged.
  86  */
  87 #ifdef _UNICOS
  88 # define SCM2PTR(x) ((int) (x) >> 3)
  89 # define PTR2SCM(x) (((SCM) (x)) << 3)
  90 # define SCM_POINTERS_MUNGED
  91 #else
  92 # define SCM2PTR(x) (x)
  93 # define PTR2SCM(x) ((SCM) (x))
  94 #endif /* def _UNICOS */
  95
  96 \f
  97 /* SCM variables can contain:
  98  *
  99  * Non-objects -- meaning that the tag-related macros don't apply to them
 100  * in the usual way.
 101  *
 102  * Immediates -- meaning that the variable contains an entire Scheme object.
 103  *
 104  * Non-immediates -- meaning that the variable holds a (possibly
 105  * tagged) pointer into the cons pair heap.
 106  *
 107  * Non-objects are distinguished from other values by careful coding
 108  * only (i.e., programmers must keep track of any SCM variables they
 109  * create that don't contain ordinary scheme values).
 110  *
 111  * All immediates and non-immediates must have a 0 in bit 0.  Only
 112  * non-object values can have a 1 in bit 0.  In some cases, bit 0 of a
 113  * word in the heap is used for the GC tag so during garbage
 114  * collection, that bit might be 1 even in an immediate or
 115  * non-immediate value.  In other cases, bit 0 of a word in the heap
 116  * is used to tag a pointer to a GLOC (VM global variable address) or
 117  * the header of a struct.  But whenever an SCM variable holds a
 118  * normal Scheme value, bit 0 is 0.
 119  *
 120  * Immediates and non-immediates are distinguished by bits two and four.
 121  * Immediate values must have a 1 in at least one of those bits.  Does
 122  * this (or any other detail of tagging) seem arbitrary?  Try changing it!
 123  * (Not always impossible but it is fair to say that many details of tags
 124  * are mutually dependent).  */
 125
 126 #define SCM_IMP(x)              (6 & SCM_UNPACK (x))
 127 #define SCM_NIMP(x)             (!SCM_IMP (x))
 128
 129 /* Here is a summary of tagging in SCM values as they might occur in
 130  * SCM variables or in the heap.
 131  *
 132  * low bits    meaning
 133  *
 134  *
 135  * 0            Most objects except...
 136  * 1            ...glocs and structs (this tag valid only in a SCM_CAR or
 137  *              in the header of a struct's data).
 138  *
 139  * 00           heap addresses and many immediates (not integers)
 140  * 01           glocs/structs, some tc7_ codes
 141  * 10           immediate integers
 142  * 11           various tc7_ codes including, tc16_ codes.
 143  *
 144  *
 145  * 000          heap address
 146  * 001          glocs/structs
 147  * 010          integer
 148  * 011          closure
 149  * 100          immediates
 150  * 101          tc7_
 151  * 110          integer
 152  * 111          tc7_
 153  *
 154  *
 155  * 100 --- IMMEDIATES
 156  *
 157  * Looking at the seven final bits of an immediate:
 158  *
 159  * 0000-100     short instruction
 160  * 0001-100     short instruction
 161  * 0010-100     short instruction
 162  * 0011-100     short instruction
 163  * 0100-100     short instruction
 164  * 0101-100     short instruction
 165  * 0110-100     various immediates and long instructions
 166  * 0111-100     short instruction
 167  * 1000-100     short instruction
 168  * 1001-100     short instruction
 169  * 1010-100     short instruction
 170  * 1011-100     short instruction
 171  * 1100-100     short instruction
 172  * 1101-100     short instruction
 173  * 1110-100     immediate characters
 174  * 1111-100     ilocs
 175  *
 176  * Some of the 0110100 immediates are long instructions (they dispatch
 177  * in two steps compared to one step for a short instruction).
 178  * The two steps are, (1) dispatch on 7 bits to the long instruction
 179  * handler, (2) dispatch on 7 additional bits.
 180  *
 181  * One way to think of it is that there are 128 short instructions,
 182  * with the 13 immediates above being some of the most interesting.
 183  *
 184  * Also noteworthy are the groups of 16 7-bit instructions implied by
 185  * some of the 3-bit tags.   For example, closure references consist
 186  * of an 8-bit aligned address tagged with 011.  There are 16 identical 7-bit
 187  * instructions, all ending 011, which are invoked by evaluating closures.
 188  *
 189  * In other words, if you hand the evaluator a closure, the evaluator
 190  * treats the closure as a graph of virtual machine instructions.
 191  * A closure is a pair with a pointer to the body of the procedure
 192  * in the CDR and a pointer to the environment of the closure in the CAR.
 193  * The environment pointer is tagged 011 which implies that the least
 194  * significant 7 bits of the environment pointer also happen to be
 195  * a virtual machine instruction we could call "SELF" (for self-evaluating
 196  * object).
 197  *
 198  * A less trivial example are the 16 instructions ending 000.  If those
 199  * bits tag the CAR of a pair, then evidently the pair is an ordinary
 200  * cons pair and should be evaluated as a procedure application.  The sixteen,
 201  * 7-bit 000 instructions are all "NORMAL-APPLY"  (Things get trickier.
 202  * For example, if the CAR of a procedure application is a symbol, the NORMAL-APPLY
 203  * instruction will, as a side effect, overwrite that CAR with a new instruction
 204  * that contains a cached address for the variable named by the symbol.)
 205  *
 206  * Here is a summary of tags in the CAR of a non-immediate:
 207  *
 208  *   HEAP CELL: G=gc_mark; 1 during mark, 0 other times.
 209  *
 210  * cons    ..........SCM car..............0  ...........SCM cdr.............G
 211  * gloc    ..........SCM vcell..........001  ...........SCM cdr.............G
 212  * struct  ..........void * type........001  ...........void * data.........G
 213  * closure ..........SCM code...........011  ...........SCM env.............G
 214  * tc7     .........long length....Gxxxx1S1  ..........void *data............
 215  *
 216  *
 217  *
 218  * 101 & 111 --- tc7_ types
 219  *
 220  *              tc7_tags are 7 bit tags ending in 1x1.  These tags
 221  *              occur only in the CAR of heap cells, and have the
 222  *              handy property that all bits of the CAR above the
 223  *              bottom eight can be used to store a length, thus
 224  *              saving a word in the body itself.  Thus, we use them
 225  *              for strings, symbols, and vectors (among other
 226  *              things).
 227  *
 228  *              SCM_LENGTH returns the bits in "length" (see the diagram).
 229  *              SCM_CHARS returns the data cast to "char *"
 230  *              SCM_CDR returns the data cast to "SCM"
 231  *              TYP7(X) returns bits 0...6 of SCM_CAR (X)
 232  *
 233  *              For the interpretation of SCM_LENGTH and SCM_CHARS
 234  *              that applies to a particular type, see the header file
 235  *              for that type.
 236  *
 237  *              Sometimes we choose the bottom seven bits carefully,
 238  *              so that the 2-valued bit (called S bit) can be masked
 239  *              off to reveal a common type.
 240  *
 241  *              TYP7S(X) returns TYP7, but masking out the option bit S.
 242  *
 243  *              For example, all strings have 0010 in the 'xxxx' bits
 244  *              in the diagram above, the S bit says whether it's a
 245  *              substring.
 246  *
 247  *              for example:
 248  *                                                      S
 249  *                      scm_tc7_string          = G0010101
 250  *                      scm_tc7_substring       = G0010111
 251  *
 252  *              TYP7S turns both string tags into tc7_string; thus,
 253  *              testing TYP7S against tc7_string is a quick way to
 254  *              test for any kind of string, shared or unshared.
 255  *
 256  *              Some TC7 types are subdivided into 256 subtypes giving
 257  *              rise to the macros:
 258  *
 259  *              TYP16
 260  *              TYP16S
 261  *              GCTYP16
 262  *
 263  *              TYP16S functions similarly wrt to TYP16 as TYP7S to TYP7,
 264  *              but a different option bit is used (bit 2 for TYP7S,
 265  *              bit 8 for TYP16S).
 266  * */
 267
 268
 269
 270 \f
 271 /* {Non-immediate values.}
 272  *
 273  * If X is non-immediate, it is necessary to look at SCM_CAR (X) to
 274  * figure out Xs type.  X may be a cons pair, in which case the value
 275  * SCM_CAR (x) will be either an immediate or non-immediate value.  X
 276  * may be something other than a cons pair, in which case the value
 277  * SCM_CAR (x) will be a non-object value.
 278  *
 279  * All immediates and non-immediates have a 0 in bit 0.  We
 280  * additionally preserve the invariant that all non-object values
 281  * stored in the SCM_CAR of a non-immediate object have a 1 in bit 1:
 282  */
 283
 284 #define SCM_SLOPPY_NCONSP(x) (1 & SCM_UNPACK_CAR (x))
 285 #define SCM_SLOPPY_CONSP(x)  (!SCM_SLOPPY_NCONSP (x))
 286
 287 #define SCM_NCONSP(x) (SCM_IMP (x) || SCM_SLOPPY_NCONSP (x))
 288 #define SCM_CONSP(x)  (SCM_NIMP (x) && SCM_SLOPPY_CONSP (x))
 289
 290
 291 /* SCM_ECONSP should be used instead of SCM_CONSP at places where GLOCS
 292  * can be expected to occur.
 293  */
 294 #define SCM_ECONSP(x) (SCM_NIMP (x) \
 295                        && (SCM_SLOPPY_CONSP (x) \
 296                            || (SCM_TYP3 (x) == 1 \
 297                                && SCM_CDR (SCM_CAR (x) - 1) != 0)))
 298 #define SCM_NECONSP(x) (SCM_IMP (x) \
 299                         || (SCM_SLOPPY_NCONSP (x) \
 300                             && (SCM_TYP3 (x) != 1 \
 301                                 || SCM_CDR (SCM_CAR (x) - 1) == 0)))
 302
 303 \f
 304
 305 #define SCM_CELLP(x)    (!SCM_NCELLP (x))
 306 #define SCM_NCELLP(x)   ((sizeof (scm_cell) - 1) & SCM_UNPACK (x))
 307
 308 #define SCM_DOUBLE_CELLP(x)     (!SCM_NDOUBLE_CELLP (x))
 309 #define SCM_NDOUBLE_CELLP(x)    ((2 * sizeof (scm_cell) - 1) & SCM_UNPACK (x))
 310
 311 /* See numbers.h for macros relating to immediate integers.
 312  */
 313
 314 #define SCM_ITAG3(x)            (7 & SCM_UNPACK (x))
 315 #define SCM_TYP3(x)             (7 & SCM_UNPACK_CAR (x))
 316 #define scm_tc3_cons            0
 317 #define scm_tc3_cons_gloc       1
 318 #define scm_tc3_int_1           2
 319 #define scm_tc3_closure          3
 320 #define scm_tc3_imm24            4
 321 #define scm_tc3_tc7_1            5
 322 #define scm_tc3_int_2            6
 323 #define scm_tc3_tc7_2            7
 324
 325
 326 /*
 327  * Do not change the three bit tags.
 328  */
 329
 330
 331 #define SCM_TYP7(x)             (0x7f &        SCM_UNPACK_CAR (x))
 332 #define SCM_TYP7S(x)            ((0x7f & ~2) & SCM_UNPACK_CAR (x))
 333
 334
 335 #define SCM_TYP16(x)            (0xffff & SCM_UNPACK_CAR (x))
 336 #define SCM_TYP16S(x)           (0xfeff & SCM_UNPACK_CAR (x))
 337 #define SCM_GCTYP16(x)          (0xff7f & SCM_UNPACK_CAR (x))
 338
 339
 340
 341 /* Testing and Changing GC Marks in Various Standard Positions
 342  */
 343 #define SCM_GCMARKP(x)          (1 & SCM_UNPACK (SCM_CDR (x)))
 344 #define SCM_GC8MARKP(x)         (0x80 & SCM_UNPACK_CAR (x))
 345 #define SCM_SETGCMARK(x)        SCM_SETOR_CDR (x, 1)
 346 #define SCM_CLRGCMARK(x)        SCM_SETAND_CDR (x, ~1L)
 347 #define SCM_SETGC8MARK(x)       SCM_SETOR_CAR (x, 0x80)
 348 #define SCM_CLRGC8MARK(x)       SCM_SETAND_CAR (x, ~0x80L)
 349
 350
 351 \f
 352
 353 /* couple */
 354 #define scm_tc7_ssymbol         5
 355 #define scm_tc7_msymbol         7
 356
 357 /* couple */
 358 #define scm_tc7_vector          13
 359 #define scm_tc7_wvect           15
 360
 361 /* couple */
 362 #define scm_tc7_string          21
 363 #define scm_tc7_substring       23
 364
 365 /* Many of the following should be turned
 366  * into structs or smobs.  We need back some
 367  * of these 7 bit tags!
 368  */
 369 #define scm_tc7_pws             31
 370 #define scm_tc7_lvector         39
 371
 372 #ifdef HAVE_ARRAYS
 373 #define scm_tc7_llvect          29
 374 #define scm_tc7_uvect           37
 375 #define scm_tc7_fvect           45
 376 #define scm_tc7_dvect           47
 377 #define scm_tc7_cvect           53
 378 #define scm_tc7_svect           55
 379 #define scm_tc7_bvect           71
 380 #define scm_tc7_byvect          77
 381 #define scm_tc7_ivect           79
 382 #endif
 383
 384 #define scm_tc7_contin          61
 385 #define scm_tc7_cclo            63
 386 #define scm_tc7_rpsubr          69
 387 #define scm_tc7_subr_0          85
 388 #define scm_tc7_subr_1          87
 389 #define scm_tc7_cxr             93
 390 #define scm_tc7_subr_3          95
 391 #define scm_tc7_subr_2          101
 392 #define scm_tc7_asubr           103
 393 #define scm_tc7_subr_1o         109
 394 #define scm_tc7_subr_2o         111
 395 #define scm_tc7_lsubr_2         117
 396 #define scm_tc7_lsubr           119
 397
 398
 399 /* There are 256 port subtypes.  Here are the first few.
 400  * These must agree with the init function in ports.c
 401  */
 402 #define scm_tc7_port            125
 403
 404 #define scm_tc16_fport          (scm_tc7_port + 0 * 256L)
 405 /* scm_tc16_pipe was here.  */
 406 #define scm_tc16_strport        (scm_tc7_port + 2 * 256L)
 407 #define scm_tc16_sfport         (scm_tc7_port + 3 * 256L)
 408
 409
 410 /* There are 256 smob subtypes.  Here are the first four.
 411  */
 412
 413 #define scm_tc7_smob            127 /* DO NOT CHANGE [**] */
 414
 415 /* [**] If you change scm_tc7_smob, you must also change
 416  * the places it is hard coded in this file and possibly others.
 417  */
 418
 419
 420 /* scm_tc_free_cell is also the 0th smob type.  We place this
 421  * in free cells to tell the conservative marker not to trace it.
 422  */
 423 #define scm_tc_free_cell        0x007f
 424
 425 /* Smob type 1 (note the dependency on the predicate SCM_NUMP)
 426  */
 427 #define scm_tc16_big            0x017f
 428
 429 /* Smob types 2 and 3:
 430  */
 431 #define scm_tc16_real           0x027f
 432 #define scm_tc16_complex        0x037f
 433
 434 /* The following four macros are now deprecated: */
 435 #define scm_tc16_flo            scm_tc16_real
 436 #define scm_tc_flo              0x017fL
 437 #define scm_tc_dblr             scm_tc16_real
 438 #define scm_tc_dblc             scm_tc16_complex
 439
 440 /* Smob type 4 allocated, but not initialized cells;
 441    this is required to prevent the gc from hosing your cells if
 442    you have to allocate while creating the cell*/
 443 #define scm_tc16_allocated      0x047f
 444
 445 \f
 446 /* {Immediate Values}
 447  */
 448
 449 enum scm_tags
 450 {
 451   scm_tc8_char = 0xf4,
 452   scm_tc8_iloc = 0xfc
 453 };
 454
 455 #define SCM_ITAG8(X)            (SCM_UNPACK (X) & 0xff)
 456 #define SCM_MAKE_ITAG8(X, TAG)  SCM_PACK (((X) << 8) + TAG)
 457 #define SCM_ITAG8_DATA(X)       (SCM_UNPACK (X) >> 8)
 458
 459
 460 \f
 461 /* Immediate Symbols, Special Symbols, Flags (various constants).
 462  */
 463
 464 /* SCM_ISYMP tests for ISPCSYM and ISYM */
 465 #define SCM_ISYMP(n)            ((0x187 & SCM_UNPACK (n)) == 4)
 466
 467 /* SCM_IFLAGP tests for ISPCSYM, ISYM and IFLAG */
 468 #define SCM_IFLAGP(n)           ((0x87 & SCM_UNPACK (n)) == 4)
 469 #define SCM_ISYMNUM(n)          (SCM_UNPACK (n) >> 9)
 470 #define SCM_ISYMCHARS(n)        (scm_isymnames[SCM_ISYMNUM (n)])
 471 #define SCM_MAKSPCSYM(n)        SCM_PACK (((n) << 9) + ((n) << 3) + 4L)
 472 #define SCM_MAKISYM(n)          SCM_PACK (((n) << 9) + 0x74L)
 473 #define SCM_MAKIFLAG(n)         SCM_PACK (((n) << 9) + 0x174L)
 474
 475 extern char *scm_isymnames[];   /* defined in print.c */
 476
 477 /* This table must agree with the declarations
 478  * in repl.c: {Names of immediate symbols}.
 479  *
 480  * These are used only in eval but their values
 481  * have to be allocated here.
 482  *
 483  */
 484
 485 #define SCM_IM_AND              SCM_MAKSPCSYM (0)
 486 #define SCM_IM_BEGIN            SCM_MAKSPCSYM (1)
 487 #define SCM_IM_CASE             SCM_MAKSPCSYM (2)
 488 #define SCM_IM_COND             SCM_MAKSPCSYM (3)
 489 #define SCM_IM_DO               SCM_MAKSPCSYM (4)
 490 #define SCM_IM_IF               SCM_MAKSPCSYM (5)
 491 #define SCM_IM_LAMBDA           SCM_MAKSPCSYM (6)
 492 #define SCM_IM_LET              SCM_MAKSPCSYM (7)
 493 #define SCM_IM_LETSTAR          SCM_MAKSPCSYM (8)
 494 #define SCM_IM_LETREC           SCM_MAKSPCSYM (9)
 495 #define SCM_IM_OR               SCM_MAKSPCSYM (10)
 496 #define SCM_IM_QUOTE            SCM_MAKSPCSYM (11)
 497 #define SCM_IM_SET_X            SCM_MAKSPCSYM (12)
 498 #define SCM_IM_DEFINE           SCM_MAKSPCSYM (13)
 499 #define SCM_IM_APPLY            SCM_MAKISYM (14)
 500 #define SCM_IM_CONT             SCM_MAKISYM (15)
 501 #define SCM_BOOL_F              SCM_MAKIFLAG (16)
 502 #define SCM_BOOL_T              SCM_MAKIFLAG (17)
 503 #define SCM_UNDEFINED           SCM_MAKIFLAG (18)
 504 #define SCM_EOF_VAL             SCM_MAKIFLAG (19)
 505 #define SCM_EOL                 SCM_MAKIFLAG (20)
 506 #define SCM_UNSPECIFIED         SCM_MAKIFLAG (21)
 507 #define SCM_IM_DISPATCH         SCM_MAKISYM (22)
 508 #define SCM_IM_SLOT_REF         SCM_MAKISYM (23)
 509 #define SCM_IM_SLOT_SET_X       SCM_MAKISYM (24)
 510
 511 /* Multi-language support */
 512
 513 #define SCM_IM_NIL_COND         SCM_MAKISYM (25)
 514 #define SCM_IM_NIL_IFY          SCM_MAKISYM (26)
 515 #define SCM_IM_T_IFY            SCM_MAKISYM (27)
 516 #define SCM_IM_0_COND           SCM_MAKISYM (28)
 517 #define SCM_IM_0_IFY            SCM_MAKISYM (29)
 518 #define SCM_IM_1_IFY            SCM_MAKISYM (30)
 519 #define SCM_IM_BIND             SCM_MAKISYM (31)
 520
 521 #define SCM_IM_DELAY            SCM_MAKISYM (32)
 522
 523 /* When a variable is unbound this is marked by the SCM_UNDEFINED
 524  * value.  The following is an unbound value which can be handled on
 525  * the Scheme level, i.e., it can be stored in and retrieved from a
 526  * Scheme variable.  This value is only intended to mark an unbound
 527  * slot in GOOPS.  It is needed now, but we should probably rewrite
 528  * the code which handles this value in C so that SCM_UNDEFINED can be
 529  * used instead.  It is not ideal to let this kind of unique and
 530  * strange values loose on the Scheme level.
 531  */
 532 #define SCM_UNBOUND             SCM_MAKIFLAG (33)
 533
 534 #define SCM_UNBNDP(x)   (SCM_UNDEFINED == (x))
 535
 536 \f
 537
 538 /* Dispatching aids: */
 539
 540
 541 /* For cons pairs with immediate values in the CAR
 542  */
 543
 544 #define scm_tcs_cons_imcar 2:case 4:case 6:case 10:\
 545  case 12:case 14:case 18:case 20:\
 546  case 22:case 26:case 28:case 30:\
 547  case 34:case 36:case 38:case 42:\
 548  case 44:case 46:case 50:case 52:\
 549  case 54:case 58:case 60:case 62:\
 550  case 66:case 68:case 70:case 74:\
 551  case 76:case 78:case 82:case 84:\
 552  case 86:case 90:case 92:case 94:\
 553  case 98:case 100:case 102:case 106:\
 554  case 108:case 110:case 114:case 116:\
 555  case 118:case 122:case 124:case 126
 556
 557 /* For cons pairs with non-immediate values in the SCM_CAR
 558  */
 559 #define scm_tcs_cons_nimcar 0:case 8:case 16:case 24:\
 560  case 32:case 40:case 48:case 56:\
 561  case 64:case 72:case 80:case 88:\
 562  case 96:case 104:case 112:case 120
 563
 564 /* A CONS_GLOC occurs in code.  It's CAR is a pointer to the
 565  * CDR of a variable.  The low order bits of the CAR are 001.
 566  * The CDR of the gloc is the code continuation.
 567  */
 568 #define scm_tcs_cons_gloc 1:case 9:case 17:case 25:\
 569  case 33:case 41:case 49:case 57:\
 570  case 65:case 73:case 81:case 89:\
 571  case 97:case 105:case 113:case 121
 572
 573 #define scm_tcs_closures   3:case 11:case 19:case 27:\
 574  case 35:case 43:case 51:case 59:\
 575  case 67:case 75:case 83:case 91:\
 576  case 99:case 107:case 115:case 123
 577
 578 #define scm_tcs_subrs scm_tc7_asubr:case scm_tc7_subr_0:case scm_tc7_subr_1:case scm_tc7_cxr:\
 579  case scm_tc7_subr_3:case scm_tc7_subr_2:case scm_tc7_rpsubr:case scm_tc7_subr_1o:\
 580  case scm_tc7_subr_2o:case scm_tc7_lsubr_2:case scm_tc7_lsubr
 581
 582 #define scm_tcs_symbols scm_tc7_ssymbol:case scm_tc7_msymbol
 583
 584 #endif  /* TAGSH */