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1 24 jeremybenn
/* Target-dependent code for the Toshiba MeP for GDB, the GNU debugger.
2
 
3
   Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
4
   Free Software Foundation, Inc.
5
 
6
   Contributed by Red Hat, Inc.
7
 
8
   This file is part of GDB.
9
 
10
   This program is free software; you can redistribute it and/or modify
11
   it under the terms of the GNU General Public License as published by
12
   the Free Software Foundation; either version 3 of the License, or
13
   (at your option) any later version.
14
 
15
   This program is distributed in the hope that it will be useful,
16
   but WITHOUT ANY WARRANTY; without even the implied warranty of
17
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18
   GNU General Public License for more details.
19
 
20
   You should have received a copy of the GNU General Public License
21
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
22
 
23
#include "defs.h"
24
#include "frame.h"
25
#include "frame-unwind.h"
26
#include "frame-base.h"
27
#include "symtab.h"
28
#include "gdbtypes.h"
29
#include "gdbcmd.h"
30
#include "gdbcore.h"
31
#include "gdb_string.h"
32
#include "value.h"
33
#include "inferior.h"
34
#include "dis-asm.h"
35
#include "symfile.h"
36
#include "objfiles.h"
37
#include "language.h"
38
#include "arch-utils.h"
39
#include "regcache.h"
40
#include "remote.h"
41
#include "floatformat.h"
42
#include "sim-regno.h"
43
#include "disasm.h"
44
#include "trad-frame.h"
45
#include "reggroups.h"
46
#include "elf-bfd.h"
47
#include "elf/mep.h"
48
#include "prologue-value.h"
49
#include "opcode/cgen-bitset.h"
50
#include "infcall.h"
51
 
52
#include "gdb_assert.h"
53
 
54
/* Get the user's customized MeP coprocessor register names from
55
   libopcodes.  */
56
#include "opcodes/mep-desc.h"
57
#include "opcodes/mep-opc.h"
58
 
59
 
60
/* The gdbarch_tdep structure.  */
61
 
62
/* A quick recap for GDB hackers not familiar with the whole Toshiba
63
   Media Processor story:
64
 
65
   The MeP media engine is a configureable processor: users can design
66
   their own coprocessors, implement custom instructions, adjust cache
67
   sizes, select optional standard facilities like add-and-saturate
68
   instructions, and so on.  Then, they can build custom versions of
69
   the GNU toolchain to support their customized chips.  The
70
   MeP-Integrator program (see utils/mep) takes a GNU toolchain source
71
   tree, and a config file pointing to various files provided by the
72
   user describing their customizations, and edits the source tree to
73
   produce a compiler that can generate their custom instructions, an
74
   assembler that can assemble them and recognize their custom
75
   register names, and so on.
76
 
77
   Furthermore, the user can actually specify several of these custom
78
   configurations, called 'me_modules', and get a toolchain which can
79
   produce code for any of them, given a compiler/assembler switch;
80
   you say something like 'gcc -mconfig=mm_max' to generate code for
81
   the me_module named 'mm_max'.
82
 
83
   GDB, in particular, needs to:
84
 
85
   - use the coprocessor control register names provided by the user
86
     in their hardware description, in expressions, 'info register'
87
     output, and disassembly,
88
 
89
   - know the number, names, and types of the coprocessor's
90
     general-purpose registers, adjust the 'info all-registers' output
91
     accordingly, and print error messages if the user refers to one
92
     that doesn't exist
93
 
94
   - allow access to the control bus space only when the configuration
95
     actually has a control bus, and recognize which regions of the
96
     control bus space are actually populated,
97
 
98
   - disassemble using the user's provided mnemonics for their custom
99
     instructions, and
100
 
101
   - recognize whether the $hi and $lo registers are present, and
102
     allow access to them only when they are actually there.
103
 
104
   There are three sources of information about what sort of me_module
105
   we're actually dealing with:
106
 
107
   - A MeP executable file indicates which me_module it was compiled
108
     for, and libopcodes has tables describing each module.  So, given
109
     an executable file, we can find out about the processor it was
110
     compiled for.
111
 
112
   - There are SID command-line options to select a particular
113
     me_module, overriding the one specified in the ELF file.  SID
114
     provides GDB with a fake read-only register, 'module', which
115
     indicates which me_module GDB is communicating with an instance
116
     of.
117
 
118
   - There are SID command-line options to enable or disable certain
119
     optional processor features, overriding the defaults for the
120
     selected me_module.  The MeP $OPT register indicates which
121
     options are present on the current processor.  */
122
 
123
 
124
struct gdbarch_tdep
125
{
126
  /* A CGEN cpu descriptor for this BFD architecture and machine.
127
 
128
     Note: this is *not* customized for any particular me_module; the
129
     MeP libopcodes machinery actually puts off module-specific
130
     customization until the last minute.  So this contains
131
     information about all supported me_modules.  */
132
  CGEN_CPU_DESC cpu_desc;
133
 
134
  /* The me_module index from the ELF file we used to select this
135
     architecture, or CONFIG_NONE if there was none.
136
 
137
     Note that we should prefer to use the me_module number available
138
     via the 'module' register, whenever we're actually talking to a
139
     real target.
140
 
141
     In the absence of live information, we'd like to get the
142
     me_module number from the ELF file.  But which ELF file: the
143
     executable file, the core file, ... ?  The answer is, "the last
144
     ELF file we used to set the current architecture".  Thus, we
145
     create a separate instance of the gdbarch structure for each
146
     me_module value mep_gdbarch_init sees, and store the me_module
147
     value from the ELF file here.  */
148
  CONFIG_ATTR me_module;
149
};
150
 
151
 
152
 
153
/* Getting me_module information from the CGEN tables.  */
154
 
155
 
156
/* Find an entry in the DESC's hardware table whose name begins with
157
   PREFIX, and whose ISA mask intersects COPRO_ISA_MASK, but does not
158
   intersect with GENERIC_ISA_MASK.  If there is no matching entry,
159
   return zero.  */
160
static const CGEN_HW_ENTRY *
161
find_hw_entry_by_prefix_and_isa (CGEN_CPU_DESC desc,
162
                                 const char *prefix,
163
                                 CGEN_BITSET *copro_isa_mask,
164
                                 CGEN_BITSET *generic_isa_mask)
165
{
166
  int prefix_len = strlen (prefix);
167
  int i;
168
 
169
  for (i = 0; i < desc->hw_table.num_entries; i++)
170
    {
171
      const CGEN_HW_ENTRY *hw = desc->hw_table.entries[i];
172
      if (strncmp (prefix, hw->name, prefix_len) == 0)
173
        {
174
          CGEN_BITSET *hw_isa_mask
175
            = ((CGEN_BITSET *)
176
               &CGEN_ATTR_CGEN_HW_ISA_VALUE (CGEN_HW_ATTRS (hw)));
177
 
178
          if (cgen_bitset_intersect_p (hw_isa_mask, copro_isa_mask)
179
              && ! cgen_bitset_intersect_p (hw_isa_mask, generic_isa_mask))
180
            return hw;
181
        }
182
    }
183
 
184
  return 0;
185
}
186
 
187
 
188
/* Find an entry in DESC's hardware table whose type is TYPE.  Return
189
   zero if there is none.  */
190
static const CGEN_HW_ENTRY *
191
find_hw_entry_by_type (CGEN_CPU_DESC desc, CGEN_HW_TYPE type)
192
{
193
  int i;
194
 
195
  for (i = 0; i < desc->hw_table.num_entries; i++)
196
    {
197
      const CGEN_HW_ENTRY *hw = desc->hw_table.entries[i];
198
 
199
      if (hw->type == type)
200
        return hw;
201
    }
202
 
203
  return 0;
204
}
205
 
206
 
207
/* Return the CGEN hardware table entry for the coprocessor register
208
   set for ME_MODULE, whose name prefix is PREFIX.  If ME_MODULE has
209
   no such register set, return zero.  If ME_MODULE is the generic
210
   me_module CONFIG_NONE, return the table entry for the register set
211
   whose hardware type is GENERIC_TYPE.  */
212
static const CGEN_HW_ENTRY *
213
me_module_register_set (CONFIG_ATTR me_module,
214
                        const char *prefix,
215
                        CGEN_HW_TYPE generic_type)
216
{
217
  /* This is kind of tricky, because the hardware table is constructed
218
     in a way that isn't very helpful.  Perhaps we can fix that, but
219
     here's how it works at the moment:
220
 
221
     The configuration map, `mep_config_map', is indexed by me_module
222
     number, and indicates which coprocessor and core ISAs that
223
     me_module supports.  The 'core_isa' mask includes all the core
224
     ISAs, and the 'cop_isa' mask includes all the coprocessor ISAs.
225
     The entry for the generic me_module, CONFIG_NONE, has an empty
226
     'cop_isa', and its 'core_isa' selects only the standard MeP
227
     instruction set.
228
 
229
     The CGEN CPU descriptor's hardware table, desc->hw_table, has
230
     entries for all the register sets, for all me_modules.  Each
231
     entry has a mask indicating which ISAs use that register set.
232
     So, if an me_module supports some coprocessor ISA, we can find
233
     applicable register sets by scanning the hardware table for
234
     register sets whose masks include (at least some of) those ISAs.
235
 
236
     Each hardware table entry also has a name, whose prefix says
237
     whether it's a general-purpose ("h-cr") or control ("h-ccr")
238
     coprocessor register set.  It might be nicer to have an attribute
239
     indicating what sort of register set it was, that we could use
240
     instead of pattern-matching on the name.
241
 
242
     When there is no hardware table entry whose mask includes a
243
     particular coprocessor ISA and whose name starts with a given
244
     prefix, then that means that that coprocessor doesn't have any
245
     registers of that type.  In such cases, this function must return
246
     a null pointer.
247
 
248
     Coprocessor register sets' masks may or may not include the core
249
     ISA for the me_module they belong to.  Those generated by a2cgen
250
     do, but the sample me_module included in the unconfigured tree,
251
     'ccfx', does not.
252
 
253
     There are generic coprocessor register sets, intended only for
254
     use with the generic me_module.  Unfortunately, their masks
255
     include *all* ISAs --- even those for coprocessors that don't
256
     have such register sets.  This makes detecting the case where a
257
     coprocessor lacks a particular register set more complicated.
258
 
259
     So, here's the approach we take:
260
 
261
     - For CONFIG_NONE, we return the generic coprocessor register set.
262
 
263
     - For any other me_module, we search for a register set whose
264
       mask contains any of the me_module's coprocessor ISAs,
265
       specifically excluding the generic coprocessor register sets.  */
266
 
267
  CGEN_CPU_DESC desc = gdbarch_tdep (current_gdbarch)->cpu_desc;
268
  const CGEN_HW_ENTRY *hw;
269
 
270
  if (me_module == CONFIG_NONE)
271
    hw = find_hw_entry_by_type (desc, generic_type);
272
  else
273
    {
274
      CGEN_BITSET *cop = &mep_config_map[me_module].cop_isa;
275
      CGEN_BITSET *core = &mep_config_map[me_module].core_isa;
276
      CGEN_BITSET *generic = &mep_config_map[CONFIG_NONE].core_isa;
277
      CGEN_BITSET *cop_and_core;
278
 
279
      /* The coprocessor ISAs include the ISA for the specific core which
280
         has that coprocessor.  */
281
      cop_and_core = cgen_bitset_copy (cop);
282
      cgen_bitset_union (cop, core, cop_and_core);
283
      hw = find_hw_entry_by_prefix_and_isa (desc, prefix, cop_and_core, generic);
284
    }
285
 
286
  return hw;
287
}
288
 
289
 
290
/* Given a hardware table entry HW representing a register set, return
291
   a pointer to the keyword table with all the register names.  If HW
292
   is NULL, return NULL, to propage the "no such register set" info
293
   along.  */
294
static CGEN_KEYWORD *
295
register_set_keyword_table (const CGEN_HW_ENTRY *hw)
296
{
297
  if (! hw)
298
    return NULL;
299
 
300
  /* Check that HW is actually a keyword table.  */
301
  gdb_assert (hw->asm_type == CGEN_ASM_KEYWORD);
302
 
303
  /* The 'asm_data' field of a register set's hardware table entry
304
     refers to a keyword table.  */
305
  return (CGEN_KEYWORD *) hw->asm_data;
306
}
307
 
308
 
309
/* Given a keyword table KEYWORD and a register number REGNUM, return
310
   the name of the register, or "" if KEYWORD contains no register
311
   whose number is REGNUM.  */
312
static char *
313
register_name_from_keyword (CGEN_KEYWORD *keyword_table, int regnum)
314
{
315
  const CGEN_KEYWORD_ENTRY *entry
316
    = cgen_keyword_lookup_value (keyword_table, regnum);
317
 
318
  if (entry)
319
    {
320
      char *name = entry->name;
321
 
322
      /* The CGEN keyword entries for register names include the
323
         leading $, which appears in MeP assembly as well as in GDB.
324
         But we don't want to return that; GDB core code adds that
325
         itself.  */
326
      if (name[0] == '$')
327
        name++;
328
 
329
      return name;
330
    }
331
  else
332
    return "";
333
}
334
 
335
 
336
/* Masks for option bits in the OPT special-purpose register.  */
337
enum {
338
  MEP_OPT_DIV = 1 << 25,        /* 32-bit divide instruction option */
339
  MEP_OPT_MUL = 1 << 24,        /* 32-bit multiply instruction option */
340
  MEP_OPT_BIT = 1 << 23,        /* bit manipulation instruction option */
341
  MEP_OPT_SAT = 1 << 22,        /* saturation instruction option */
342
  MEP_OPT_CLP = 1 << 21,        /* clip instruction option */
343
  MEP_OPT_MIN = 1 << 20,        /* min/max instruction option */
344
  MEP_OPT_AVE = 1 << 19,        /* average instruction option */
345
  MEP_OPT_ABS = 1 << 18,        /* absolute difference instruction option */
346
  MEP_OPT_LDZ = 1 << 16,        /* leading zero instruction option */
347
  MEP_OPT_VL64 = 1 << 6,        /* 64-bit VLIW operation mode option */
348
  MEP_OPT_VL32 = 1 << 5,        /* 32-bit VLIW operation mode option */
349
  MEP_OPT_COP = 1 << 4,         /* coprocessor option */
350
  MEP_OPT_DSP = 1 << 2,         /* DSP option */
351
  MEP_OPT_UCI = 1 << 1,         /* UCI option */
352
  MEP_OPT_DBG = 1 << 0,         /* DBG function option */
353
};
354
 
355
 
356
/* Given the option_mask value for a particular entry in
357
   mep_config_map, produce the value the processor's OPT register
358
   would use to represent the same set of options.  */
359
static unsigned int
360
opt_from_option_mask (unsigned int option_mask)
361
{
362
  /* A table mapping OPT register bits onto CGEN config map option
363
     bits.  */
364
  struct {
365
    unsigned int opt_bit, option_mask_bit;
366
  } bits[] = {
367
    { MEP_OPT_DIV, 1 << CGEN_INSN_OPTIONAL_DIV_INSN },
368
    { MEP_OPT_MUL, 1 << CGEN_INSN_OPTIONAL_MUL_INSN },
369
    { MEP_OPT_DIV, 1 << CGEN_INSN_OPTIONAL_DIV_INSN },
370
    { MEP_OPT_DBG, 1 << CGEN_INSN_OPTIONAL_DEBUG_INSN },
371
    { MEP_OPT_LDZ, 1 << CGEN_INSN_OPTIONAL_LDZ_INSN },
372
    { MEP_OPT_ABS, 1 << CGEN_INSN_OPTIONAL_ABS_INSN },
373
    { MEP_OPT_AVE, 1 << CGEN_INSN_OPTIONAL_AVE_INSN },
374
    { MEP_OPT_MIN, 1 << CGEN_INSN_OPTIONAL_MINMAX_INSN },
375
    { MEP_OPT_CLP, 1 << CGEN_INSN_OPTIONAL_CLIP_INSN },
376
    { MEP_OPT_SAT, 1 << CGEN_INSN_OPTIONAL_SAT_INSN },
377
    { MEP_OPT_UCI, 1 << CGEN_INSN_OPTIONAL_UCI_INSN },
378
    { MEP_OPT_DSP, 1 << CGEN_INSN_OPTIONAL_DSP_INSN },
379
    { MEP_OPT_COP, 1 << CGEN_INSN_OPTIONAL_CP_INSN },
380
  };
381
 
382
  int i;
383
  unsigned int opt = 0;
384
 
385
  for (i = 0; i < (sizeof (bits) / sizeof (bits[0])); i++)
386
    if (option_mask & bits[i].option_mask_bit)
387
      opt |= bits[i].opt_bit;
388
 
389
  return opt;
390
}
391
 
392
 
393
/* Return the value the $OPT register would use to represent the set
394
   of options for ME_MODULE.  */
395
static unsigned int
396
me_module_opt (CONFIG_ATTR me_module)
397
{
398
  return opt_from_option_mask (mep_config_map[me_module].option_mask);
399
}
400
 
401
 
402
/* Return the width of ME_MODULE's coprocessor data bus, in bits.
403
   This is either 32 or 64.  */
404
static int
405
me_module_cop_data_bus_width (CONFIG_ATTR me_module)
406
{
407
  if (mep_config_map[me_module].option_mask
408
      & (1 << CGEN_INSN_OPTIONAL_CP64_INSN))
409
    return 64;
410
  else
411
    return 32;
412
}
413
 
414
 
415
/* Return true if ME_MODULE is big-endian, false otherwise.  */
416
static int
417
me_module_big_endian (CONFIG_ATTR me_module)
418
{
419
  return mep_config_map[me_module].big_endian;
420
}
421
 
422
 
423
/* Return the name of ME_MODULE, or NULL if it has no name.  */
424
static const char *
425
me_module_name (CONFIG_ATTR me_module)
426
{
427
  /* The default me_module has "" as its name, but it's easier for our
428
     callers to test for NULL.  */
429
  if (! mep_config_map[me_module].name
430
      || mep_config_map[me_module].name[0] == '\0')
431
    return NULL;
432
  else
433
    return mep_config_map[me_module].name;
434
}
435
 
436
/* Register set.  */
437
 
438
 
439
/* The MeP spec defines the following registers:
440
   16 general purpose registers (r0-r15)
441
   32 control/special registers (csr0-csr31)
442
   32 coprocessor general-purpose registers (c0 -- c31)
443
   64 coprocessor control registers (ccr0 -- ccr63)
444
 
445
   For the raw registers, we assign numbers here explicitly, instead
446
   of letting the enum assign them for us; the numbers are a matter of
447
   external protocol, and shouldn't shift around as things are edited.
448
 
449
   We access the control/special registers via pseudoregisters, to
450
   enforce read-only portions that some registers have.
451
 
452
   We access the coprocessor general purpose and control registers via
453
   pseudoregisters, to make sure they appear in the proper order in
454
   the 'info all-registers' command (which uses the register number
455
   ordering), and also to allow them to be renamed and resized
456
   depending on the me_module in use.
457
 
458
   The MeP allows coprocessor general-purpose registers to be either
459
   32 or 64 bits long, depending on the configuration.  Since we don't
460
   want the format of the 'g' packet to vary from one core to another,
461
   the raw coprocessor GPRs are always 64 bits.  GDB doesn't allow the
462
   types of registers to change (see the implementation of
463
   register_type), so we have four banks of pseudoregisters for the
464
   coprocessor gprs --- 32-bit vs. 64-bit, and integer
465
   vs. floating-point --- and we show or hide them depending on the
466
   configuration.  */
467
enum
468
{
469
  MEP_FIRST_RAW_REGNUM = 0,
470
 
471
  MEP_FIRST_GPR_REGNUM = 0,
472
  MEP_R0_REGNUM = 0,
473
  MEP_R1_REGNUM = 1,
474
  MEP_R2_REGNUM = 2,
475
  MEP_R3_REGNUM = 3,
476
  MEP_R4_REGNUM = 4,
477
  MEP_R5_REGNUM = 5,
478
  MEP_R6_REGNUM = 6,
479
  MEP_R7_REGNUM = 7,
480
  MEP_R8_REGNUM = 8,
481
  MEP_R9_REGNUM = 9,
482
  MEP_R10_REGNUM = 10,
483
  MEP_R11_REGNUM = 11,
484
  MEP_R12_REGNUM = 12,
485
  MEP_FP_REGNUM = MEP_R8_REGNUM,
486
  MEP_R13_REGNUM = 13,
487
  MEP_TP_REGNUM = MEP_R13_REGNUM,       /* (r13) Tiny data pointer */
488
  MEP_R14_REGNUM = 14,
489
  MEP_GP_REGNUM = MEP_R14_REGNUM,       /* (r14) Global pointer */
490
  MEP_R15_REGNUM = 15,
491
  MEP_SP_REGNUM = MEP_R15_REGNUM,       /* (r15) Stack pointer */
492
  MEP_LAST_GPR_REGNUM = MEP_R15_REGNUM,
493
 
494
  /* The raw control registers.  These are the values as received via
495
     the remote protocol, directly from the target; we only let user
496
     code touch the via the pseudoregisters, which enforce read-only
497
     bits.  */
498
  MEP_FIRST_RAW_CSR_REGNUM = 16,
499
  MEP_RAW_PC_REGNUM    = 16,    /* Program counter */
500
  MEP_RAW_LP_REGNUM    = 17,    /* Link pointer */
501
  MEP_RAW_SAR_REGNUM   = 18,    /* Raw shift amount */
502
  MEP_RAW_CSR3_REGNUM  = 19,    /* csr3: reserved */
503
  MEP_RAW_RPB_REGNUM   = 20,    /* Raw repeat begin address */
504
  MEP_RAW_RPE_REGNUM   = 21,    /* Repeat end address */
505
  MEP_RAW_RPC_REGNUM   = 22,    /* Repeat count */
506
  MEP_RAW_HI_REGNUM    = 23, /* Upper 32 bits of result of 64 bit mult/div */
507
  MEP_RAW_LO_REGNUM    = 24, /* Lower 32 bits of result of 64 bit mult/div */
508
  MEP_RAW_CSR9_REGNUM  = 25,    /* csr3: reserved */
509
  MEP_RAW_CSR10_REGNUM = 26,    /* csr3: reserved */
510
  MEP_RAW_CSR11_REGNUM = 27,    /* csr3: reserved */
511
  MEP_RAW_MB0_REGNUM   = 28,    /* Raw modulo begin address 0 */
512
  MEP_RAW_ME0_REGNUM   = 29,    /* Raw modulo end address 0 */
513
  MEP_RAW_MB1_REGNUM   = 30,    /* Raw modulo begin address 1 */
514
  MEP_RAW_ME1_REGNUM   = 31,    /* Raw modulo end address 1 */
515
  MEP_RAW_PSW_REGNUM   = 32,    /* Raw program status word */
516
  MEP_RAW_ID_REGNUM    = 33,    /* Raw processor ID/revision */
517
  MEP_RAW_TMP_REGNUM   = 34,    /* Temporary */
518
  MEP_RAW_EPC_REGNUM   = 35,    /* Exception program counter */
519
  MEP_RAW_EXC_REGNUM   = 36,    /* Raw exception cause */
520
  MEP_RAW_CFG_REGNUM   = 37,    /* Raw processor configuration*/
521
  MEP_RAW_CSR22_REGNUM = 38,    /* csr3: reserved */
522
  MEP_RAW_NPC_REGNUM   = 39,    /* Nonmaskable interrupt PC */
523
  MEP_RAW_DBG_REGNUM   = 40,    /* Raw debug */
524
  MEP_RAW_DEPC_REGNUM  = 41,    /* Debug exception PC */
525
  MEP_RAW_OPT_REGNUM   = 42,    /* Raw options */
526
  MEP_RAW_RCFG_REGNUM  = 43,    /* Raw local ram config */
527
  MEP_RAW_CCFG_REGNUM  = 44,    /* Raw cache config */
528
  MEP_RAW_CSR29_REGNUM = 45,    /* csr3: reserved */
529
  MEP_RAW_CSR30_REGNUM = 46,    /* csr3: reserved */
530
  MEP_RAW_CSR31_REGNUM = 47,    /* csr3: reserved */
531
  MEP_LAST_RAW_CSR_REGNUM = MEP_RAW_CSR31_REGNUM,
532
 
533
  /* The raw coprocessor general-purpose registers.  These are all 64
534
     bits wide.  */
535
  MEP_FIRST_RAW_CR_REGNUM = 48,
536
  MEP_LAST_RAW_CR_REGNUM = MEP_FIRST_RAW_CR_REGNUM + 31,
537
 
538
  MEP_FIRST_RAW_CCR_REGNUM = 80,
539
  MEP_LAST_RAW_CCR_REGNUM = MEP_FIRST_RAW_CCR_REGNUM + 63,
540
 
541
  /* The module number register.  This is the index of the me_module
542
     of which the current target is an instance.  (This is not a real
543
     MeP-specified register; it's provided by SID.)  */
544
  MEP_MODULE_REGNUM,
545
 
546
  MEP_LAST_RAW_REGNUM = MEP_MODULE_REGNUM,
547
 
548
  MEP_NUM_RAW_REGS = MEP_LAST_RAW_REGNUM + 1,
549
 
550
  /* Pseudoregisters.  See mep_pseudo_register_read and
551
     mep_pseudo_register_write.  */
552
  MEP_FIRST_PSEUDO_REGNUM = MEP_NUM_RAW_REGS,
553
 
554
  /* We have a pseudoregister for every control/special register, to
555
     implement registers with read-only bits.  */
556
  MEP_FIRST_CSR_REGNUM = MEP_FIRST_PSEUDO_REGNUM,
557
  MEP_PC_REGNUM = MEP_FIRST_CSR_REGNUM, /* Program counter */
558
  MEP_LP_REGNUM,                /* Link pointer */
559
  MEP_SAR_REGNUM,               /* shift amount */
560
  MEP_CSR3_REGNUM,              /* csr3: reserved */
561
  MEP_RPB_REGNUM,               /* repeat begin address */
562
  MEP_RPE_REGNUM,               /* Repeat end address */
563
  MEP_RPC_REGNUM,               /* Repeat count */
564
  MEP_HI_REGNUM,  /* Upper 32 bits of the result of 64 bit mult/div */
565
  MEP_LO_REGNUM,  /* Lower 32 bits of the result of 64 bit mult/div */
566
  MEP_CSR9_REGNUM,              /* csr3: reserved */
567
  MEP_CSR10_REGNUM,             /* csr3: reserved */
568
  MEP_CSR11_REGNUM,             /* csr3: reserved */
569
  MEP_MB0_REGNUM,               /* modulo begin address 0 */
570
  MEP_ME0_REGNUM,               /* modulo end address 0 */
571
  MEP_MB1_REGNUM,               /* modulo begin address 1 */
572
  MEP_ME1_REGNUM,               /* modulo end address 1 */
573
  MEP_PSW_REGNUM,               /* program status word */
574
  MEP_ID_REGNUM,                /* processor ID/revision */
575
  MEP_TMP_REGNUM,               /* Temporary */
576
  MEP_EPC_REGNUM,               /* Exception program counter */
577
  MEP_EXC_REGNUM,               /* exception cause */
578
  MEP_CFG_REGNUM,               /* processor configuration*/
579
  MEP_CSR22_REGNUM,             /* csr3: reserved */
580
  MEP_NPC_REGNUM,               /* Nonmaskable interrupt PC */
581
  MEP_DBG_REGNUM,               /* debug */
582
  MEP_DEPC_REGNUM,              /* Debug exception PC */
583
  MEP_OPT_REGNUM,               /* options */
584
  MEP_RCFG_REGNUM,              /* local ram config */
585
  MEP_CCFG_REGNUM,              /* cache config */
586
  MEP_CSR29_REGNUM,             /* csr3: reserved */
587
  MEP_CSR30_REGNUM,             /* csr3: reserved */
588
  MEP_CSR31_REGNUM,             /* csr3: reserved */
589
  MEP_LAST_CSR_REGNUM = MEP_CSR31_REGNUM,
590
 
591
  /* The 32-bit integer view of the coprocessor GPR's.  */
592
  MEP_FIRST_CR32_REGNUM,
593
  MEP_LAST_CR32_REGNUM = MEP_FIRST_CR32_REGNUM + 31,
594
 
595
  /* The 32-bit floating-point view of the coprocessor GPR's.  */
596
  MEP_FIRST_FP_CR32_REGNUM,
597
  MEP_LAST_FP_CR32_REGNUM = MEP_FIRST_FP_CR32_REGNUM + 31,
598
 
599
  /* The 64-bit integer view of the coprocessor GPR's.  */
600
  MEP_FIRST_CR64_REGNUM,
601
  MEP_LAST_CR64_REGNUM = MEP_FIRST_CR64_REGNUM + 31,
602
 
603
  /* The 64-bit floating-point view of the coprocessor GPR's.  */
604
  MEP_FIRST_FP_CR64_REGNUM,
605
  MEP_LAST_FP_CR64_REGNUM = MEP_FIRST_FP_CR64_REGNUM + 31,
606
 
607
  MEP_FIRST_CCR_REGNUM,
608
  MEP_LAST_CCR_REGNUM = MEP_FIRST_CCR_REGNUM + 63,
609
 
610
  MEP_LAST_PSEUDO_REGNUM = MEP_LAST_CCR_REGNUM,
611
 
612
  MEP_NUM_PSEUDO_REGS = (MEP_LAST_PSEUDO_REGNUM - MEP_LAST_RAW_REGNUM),
613
 
614
  MEP_NUM_REGS = MEP_NUM_RAW_REGS + MEP_NUM_PSEUDO_REGS
615
};
616
 
617
 
618
#define IN_SET(set, n) \
619
  (MEP_FIRST_ ## set ## _REGNUM <= (n) && (n) <= MEP_LAST_ ## set ## _REGNUM)
620
 
621
#define IS_GPR_REGNUM(n)     (IN_SET (GPR,     (n)))
622
#define IS_RAW_CSR_REGNUM(n) (IN_SET (RAW_CSR, (n)))
623
#define IS_RAW_CR_REGNUM(n)  (IN_SET (RAW_CR,  (n)))
624
#define IS_RAW_CCR_REGNUM(n) (IN_SET (RAW_CCR, (n)))
625
 
626
#define IS_CSR_REGNUM(n)     (IN_SET (CSR,     (n)))
627
#define IS_CR32_REGNUM(n)    (IN_SET (CR32,    (n)))
628
#define IS_FP_CR32_REGNUM(n) (IN_SET (FP_CR32, (n)))
629
#define IS_CR64_REGNUM(n)    (IN_SET (CR64,    (n)))
630
#define IS_FP_CR64_REGNUM(n) (IN_SET (FP_CR64, (n)))
631
#define IS_CR_REGNUM(n)      (IS_CR32_REGNUM (n) || IS_FP_CR32_REGNUM (n) \
632
                              || IS_CR64_REGNUM (n) || IS_FP_CR64_REGNUM (n))
633
#define IS_CCR_REGNUM(n)     (IN_SET (CCR,     (n)))
634
 
635
#define IS_RAW_REGNUM(n)     (IN_SET (RAW,     (n)))
636
#define IS_PSEUDO_REGNUM(n)  (IN_SET (PSEUDO,  (n)))
637
 
638
#define NUM_REGS_IN_SET(set) \
639
  (MEP_LAST_ ## set ## _REGNUM - MEP_FIRST_ ## set ## _REGNUM + 1)
640
 
641
#define MEP_GPR_SIZE (4)        /* Size of a MeP general-purpose register.  */
642
#define MEP_PSW_SIZE (4)        /* Size of the PSW register.  */
643
#define MEP_LP_SIZE (4)         /* Size of the LP register.  */
644
 
645
 
646
/* Many of the control/special registers contain bits that cannot be
647
   written to; some are entirely read-only.  So we present them all as
648
   pseudoregisters.
649
 
650
   The following table describes the special properties of each CSR.  */
651
struct mep_csr_register
652
{
653
  /* The number of this CSR's raw register.  */
654
  int raw;
655
 
656
  /* The number of this CSR's pseudoregister.  */
657
  int pseudo;
658
 
659
  /* A mask of the bits that are writeable: if a bit is set here, then
660
     it can be modified; if the bit is clear, then it cannot.  */
661
  LONGEST writeable_bits;
662
};
663
 
664
 
665
/* mep_csr_registers[i] describes the i'th CSR.
666
   We just list the register numbers here explicitly to help catch
667
   typos.  */
668
#define CSR(name) MEP_RAW_ ## name ## _REGNUM, MEP_ ## name ## _REGNUM
669
struct mep_csr_register mep_csr_registers[] = {
670
  { CSR(PC),    0xffffffff },   /* manual says r/o, but we can write it */
671
  { CSR(LP),    0xffffffff },
672
  { CSR(SAR),   0x0000003f },
673
  { CSR(CSR3),  0xffffffff },
674
  { CSR(RPB),   0xfffffffe },
675
  { CSR(RPE),   0xffffffff },
676
  { CSR(RPC),   0xffffffff },
677
  { CSR(HI),    0xffffffff },
678
  { CSR(LO),    0xffffffff },
679
  { CSR(CSR9),  0xffffffff },
680
  { CSR(CSR10), 0xffffffff },
681
  { CSR(CSR11), 0xffffffff },
682
  { CSR(MB0),   0x0000ffff },
683
  { CSR(ME0),   0x0000ffff },
684
  { CSR(MB1),   0x0000ffff },
685
  { CSR(ME1),   0x0000ffff },
686
  { CSR(PSW),   0x000003ff },
687
  { CSR(ID),    0x00000000 },
688
  { CSR(TMP),   0xffffffff },
689
  { CSR(EPC),   0xffffffff },
690
  { CSR(EXC),   0x000030f0 },
691
  { CSR(CFG),   0x00c0001b },
692
  { CSR(CSR22), 0xffffffff },
693
  { CSR(NPC),   0xffffffff },
694
  { CSR(DBG),   0x00000580 },
695
  { CSR(DEPC),  0xffffffff },
696
  { CSR(OPT),   0x00000000 },
697
  { CSR(RCFG),  0x00000000 },
698
  { CSR(CCFG),  0x00000000 },
699
  { CSR(CSR29), 0xffffffff },
700
  { CSR(CSR30), 0xffffffff },
701
  { CSR(CSR31), 0xffffffff },
702
};
703
 
704
 
705
/* If R is the number of a raw register, then mep_raw_to_pseudo[R] is
706
   the number of the corresponding pseudoregister.  Otherwise,
707
   mep_raw_to_pseudo[R] == R.  */
708
static int mep_raw_to_pseudo[MEP_NUM_REGS];
709
 
710
/* If R is the number of a pseudoregister, then mep_pseudo_to_raw[R]
711
   is the number of the underlying raw register.  Otherwise
712
   mep_pseudo_to_raw[R] == R.  */
713
static int mep_pseudo_to_raw[MEP_NUM_REGS];
714
 
715
static void
716
mep_init_pseudoregister_maps (void)
717
{
718
  int i;
719
 
720
  /* Verify that mep_csr_registers covers all the CSRs, in order.  */
721
  gdb_assert (ARRAY_SIZE (mep_csr_registers) == NUM_REGS_IN_SET (CSR));
722
  gdb_assert (ARRAY_SIZE (mep_csr_registers) == NUM_REGS_IN_SET (RAW_CSR));
723
 
724
  /* Verify that the raw and pseudo ranges have matching sizes.  */
725
  gdb_assert (NUM_REGS_IN_SET (RAW_CSR) == NUM_REGS_IN_SET (CSR));
726
  gdb_assert (NUM_REGS_IN_SET (RAW_CR)  == NUM_REGS_IN_SET (CR32));
727
  gdb_assert (NUM_REGS_IN_SET (RAW_CR)  == NUM_REGS_IN_SET (CR64));
728
  gdb_assert (NUM_REGS_IN_SET (RAW_CCR) == NUM_REGS_IN_SET (CCR));
729
 
730
  for (i = 0; i < ARRAY_SIZE (mep_csr_registers); i++)
731
    {
732
      struct mep_csr_register *r = &mep_csr_registers[i];
733
 
734
      gdb_assert (r->pseudo == MEP_FIRST_CSR_REGNUM + i);
735
      gdb_assert (r->raw    == MEP_FIRST_RAW_CSR_REGNUM + i);
736
    }
737
 
738
  /* Set up the initial  raw<->pseudo mappings.  */
739
  for (i = 0; i < MEP_NUM_REGS; i++)
740
    {
741
      mep_raw_to_pseudo[i] = i;
742
      mep_pseudo_to_raw[i] = i;
743
    }
744
 
745
  /* Add the CSR raw<->pseudo mappings.  */
746
  for (i = 0; i < ARRAY_SIZE (mep_csr_registers); i++)
747
    {
748
      struct mep_csr_register *r = &mep_csr_registers[i];
749
 
750
      mep_raw_to_pseudo[r->raw] = r->pseudo;
751
      mep_pseudo_to_raw[r->pseudo] = r->raw;
752
    }
753
 
754
  /* Add the CR raw<->pseudo mappings.  */
755
  for (i = 0; i < NUM_REGS_IN_SET (RAW_CR); i++)
756
    {
757
      int raw = MEP_FIRST_RAW_CR_REGNUM + i;
758
      int pseudo32 = MEP_FIRST_CR32_REGNUM + i;
759
      int pseudofp32 = MEP_FIRST_FP_CR32_REGNUM + i;
760
      int pseudo64 = MEP_FIRST_CR64_REGNUM + i;
761
      int pseudofp64 = MEP_FIRST_FP_CR64_REGNUM + i;
762
 
763
      /* Truly, the raw->pseudo mapping depends on the current module.
764
         But we use the raw->pseudo mapping when we read the debugging
765
         info; at that point, we don't know what module we'll actually
766
         be running yet.  So, we always supply the 64-bit register
767
         numbers; GDB knows how to pick a smaller value out of a
768
         larger register properly.  */
769
      mep_raw_to_pseudo[raw] = pseudo64;
770
      mep_pseudo_to_raw[pseudo32] = raw;
771
      mep_pseudo_to_raw[pseudofp32] = raw;
772
      mep_pseudo_to_raw[pseudo64] = raw;
773
      mep_pseudo_to_raw[pseudofp64] = raw;
774
    }
775
 
776
  /* Add the CCR raw<->pseudo mappings.  */
777
  for (i = 0; i < NUM_REGS_IN_SET (CCR); i++)
778
    {
779
      int raw = MEP_FIRST_RAW_CCR_REGNUM + i;
780
      int pseudo = MEP_FIRST_CCR_REGNUM + i;
781
      mep_raw_to_pseudo[raw] = pseudo;
782
      mep_pseudo_to_raw[pseudo] = raw;
783
    }
784
}
785
 
786
 
787
static int
788
mep_debug_reg_to_regnum (struct gdbarch *gdbarch, int debug_reg)
789
{
790
  /* The debug info uses the raw register numbers.  */
791
  return mep_raw_to_pseudo[debug_reg];
792
}
793
 
794
 
795
/* Return the size, in bits, of the coprocessor pseudoregister
796
   numbered PSEUDO.  */
797
static int
798
mep_pseudo_cr_size (int pseudo)
799
{
800
  if (IS_CR32_REGNUM (pseudo)
801
      || IS_FP_CR32_REGNUM (pseudo))
802
    return 32;
803
  else if (IS_CR64_REGNUM (pseudo)
804
           || IS_FP_CR64_REGNUM (pseudo))
805
    return 64;
806
  else
807
    gdb_assert (0);
808
}
809
 
810
 
811
/* If the coprocessor pseudoregister numbered PSEUDO is a
812
   floating-point register, return non-zero; if it is an integer
813
   register, return zero.  */
814
static int
815
mep_pseudo_cr_is_float (int pseudo)
816
{
817
  return (IS_FP_CR32_REGNUM (pseudo)
818
          || IS_FP_CR64_REGNUM (pseudo));
819
}
820
 
821
 
822
/* Given a coprocessor GPR pseudoregister number, return its index
823
   within that register bank.  */
824
static int
825
mep_pseudo_cr_index (int pseudo)
826
{
827
  if (IS_CR32_REGNUM (pseudo))
828
    return pseudo - MEP_FIRST_CR32_REGNUM;
829
  else if (IS_FP_CR32_REGNUM (pseudo))
830
      return pseudo - MEP_FIRST_FP_CR32_REGNUM;
831
  else if (IS_CR64_REGNUM (pseudo))
832
      return pseudo - MEP_FIRST_CR64_REGNUM;
833
  else if (IS_FP_CR64_REGNUM (pseudo))
834
      return pseudo - MEP_FIRST_FP_CR64_REGNUM;
835
  else
836
    gdb_assert (0);
837
}
838
 
839
 
840
/* Return the me_module index describing the current target.
841
 
842
   If the current target has registers (e.g., simulator, remote
843
   target), then this uses the value of the 'module' register, raw
844
   register MEP_MODULE_REGNUM.  Otherwise, this retrieves the value
845
   from the ELF header's e_flags field of the current executable
846
   file.  */
847
static CONFIG_ATTR
848
current_me_module ()
849
{
850
  if (target_has_registers)
851
    {
852
      ULONGEST regval;
853
      regcache_cooked_read_unsigned (get_current_regcache (),
854
                                     MEP_MODULE_REGNUM, &regval);
855
      return regval;
856
    }
857
  else
858
    return gdbarch_tdep (current_gdbarch)->me_module;
859
}
860
 
861
 
862
/* Return the set of options for the current target, in the form that
863
   the OPT register would use.
864
 
865
   If the current target has registers (e.g., simulator, remote
866
   target), then this is the actual value of the OPT register.  If the
867
   current target does not have registers (e.g., an executable file),
868
   then use the 'module_opt' field we computed when we build the
869
   gdbarch object for this module.  */
870
static unsigned int
871
current_options ()
872
{
873
  if (target_has_registers)
874
    {
875
      ULONGEST regval;
876
      regcache_cooked_read_unsigned (get_current_regcache (),
877
                                     MEP_OPT_REGNUM, &regval);
878
      return regval;
879
    }
880
  else
881
    return me_module_opt (current_me_module ());
882
}
883
 
884
 
885
/* Return the width of the current me_module's coprocessor data bus,
886
   in bits.  This is either 32 or 64.  */
887
static int
888
current_cop_data_bus_width ()
889
{
890
  return me_module_cop_data_bus_width (current_me_module ());
891
}
892
 
893
 
894
/* Return the keyword table of coprocessor general-purpose register
895
   names appropriate for the me_module we're dealing with.  */
896
static CGEN_KEYWORD *
897
current_cr_names ()
898
{
899
  const CGEN_HW_ENTRY *hw
900
    = me_module_register_set (current_me_module (), "h-cr-", HW_H_CR);
901
 
902
  return register_set_keyword_table (hw);
903
}
904
 
905
 
906
/* Return non-zero if the coprocessor general-purpose registers are
907
   floating-point values, zero otherwise.  */
908
static int
909
current_cr_is_float ()
910
{
911
  const CGEN_HW_ENTRY *hw
912
    = me_module_register_set (current_me_module (), "h-cr-", HW_H_CR);
913
 
914
  return CGEN_ATTR_CGEN_HW_IS_FLOAT_VALUE (CGEN_HW_ATTRS (hw));
915
}
916
 
917
 
918
/* Return the keyword table of coprocessor control register names
919
   appropriate for the me_module we're dealing with.  */
920
static CGEN_KEYWORD *
921
current_ccr_names ()
922
{
923
  const CGEN_HW_ENTRY *hw
924
    = me_module_register_set (current_me_module (), "h-ccr-", HW_H_CCR);
925
 
926
  return register_set_keyword_table (hw);
927
}
928
 
929
 
930
static const char *
931
mep_register_name (struct gdbarch *gdbarch, int regnr)
932
{
933
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
934
 
935
  /* General-purpose registers.  */
936
  static const char *gpr_names[] = {
937
    "r0",   "r1",   "r2",   "r3",   /* 0 */
938
    "r4",   "r5",   "r6",   "r7",   /* 4 */
939
    "fp",   "r9",   "r10",  "r11",  /* 8 */
940
    "r12",  "tp",   "gp",   "sp"    /* 12 */
941
  };
942
 
943
  /* Special-purpose registers.  */
944
  static const char *csr_names[] = {
945
    "pc",   "lp",   "sar",  "",     /* 0  csr3: reserved */
946
    "rpb",  "rpe",  "rpc",  "hi",   /* 4 */
947
    "lo",   "",     "",     "",     /* 8  csr9-csr11: reserved */
948
    "mb0",  "me0",  "mb1",  "me1",  /* 12 */
949
 
950
    "psw",  "id",   "tmp",  "epc",  /* 16 */
951
    "exc",  "cfg",  "",     "npc",  /* 20  csr22: reserved */
952
    "dbg",  "depc", "opt",  "rcfg", /* 24 */
953
    "ccfg", "",     "",     ""      /* 28  csr29-csr31: reserved */
954
  };
955
 
956
  if (IS_GPR_REGNUM (regnr))
957
    return gpr_names[regnr - MEP_R0_REGNUM];
958
  else if (IS_CSR_REGNUM (regnr))
959
    {
960
      /* The 'hi' and 'lo' registers are only present on processors
961
         that have the 'MUL' or 'DIV' instructions enabled.  */
962
      if ((regnr == MEP_HI_REGNUM || regnr == MEP_LO_REGNUM)
963
          && (! (current_options () & (MEP_OPT_MUL | MEP_OPT_DIV))))
964
        return "";
965
 
966
      return csr_names[regnr - MEP_FIRST_CSR_REGNUM];
967
    }
968
  else if (IS_CR_REGNUM (regnr))
969
    {
970
      CGEN_KEYWORD *names;
971
      int cr_size;
972
      int cr_is_float;
973
 
974
      /* Does this module have a coprocessor at all?  */
975
      if (! (current_options () & MEP_OPT_COP))
976
        return "";
977
 
978
      names = current_cr_names ();
979
      if (! names)
980
        /* This module's coprocessor has no general-purpose registers.  */
981
        return "";
982
 
983
      cr_size = current_cop_data_bus_width ();
984
      if (cr_size != mep_pseudo_cr_size (regnr))
985
        /* This module's coprocessor's GPR's are of a different size.  */
986
        return "";
987
 
988
      cr_is_float = current_cr_is_float ();
989
      /* The extra ! operators ensure we get boolean equality, not
990
         numeric equality.  */
991
      if (! cr_is_float != ! mep_pseudo_cr_is_float (regnr))
992
        /* This module's coprocessor's GPR's are of a different type.  */
993
        return "";
994
 
995
      return register_name_from_keyword (names, mep_pseudo_cr_index (regnr));
996
    }
997
  else if (IS_CCR_REGNUM (regnr))
998
    {
999
      /* Does this module have a coprocessor at all?  */
1000
      if (! (current_options () & MEP_OPT_COP))
1001
        return "";
1002
 
1003
      {
1004
        CGEN_KEYWORD *names = current_ccr_names ();
1005
 
1006
        if (! names)
1007
          /* This me_module's coprocessor has no control registers.  */
1008
          return "";
1009
 
1010
        return register_name_from_keyword (names, regnr-MEP_FIRST_CCR_REGNUM);
1011
      }
1012
    }
1013
 
1014
  /* It might be nice to give the 'module' register a name, but that
1015
     would affect the output of 'info all-registers', which would
1016
     disturb the test suites.  So we leave it invisible.  */
1017
  else
1018
    return NULL;
1019
}
1020
 
1021
 
1022
/* Custom register groups for the MeP.  */
1023
static struct reggroup *mep_csr_reggroup; /* control/special */
1024
static struct reggroup *mep_cr_reggroup;  /* coprocessor general-purpose */
1025
static struct reggroup *mep_ccr_reggroup; /* coprocessor control */
1026
 
1027
 
1028
static int
1029
mep_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
1030
                         struct reggroup *group)
1031
{
1032
  /* Filter reserved or unused register numbers.  */
1033
  {
1034
    const char *name = mep_register_name (gdbarch, regnum);
1035
 
1036
    if (! name || name[0] == '\0')
1037
      return 0;
1038
  }
1039
 
1040
  /* We could separate the GPRs and the CSRs.  Toshiba has approved of
1041
     the existing behavior, so we'd want to run that by them.  */
1042
  if (group == general_reggroup)
1043
    return (IS_GPR_REGNUM (regnum)
1044
            || IS_CSR_REGNUM (regnum));
1045
 
1046
  /* Everything is in the 'all' reggroup, except for the raw CSR's.  */
1047
  else if (group == all_reggroup)
1048
    return (IS_GPR_REGNUM (regnum)
1049
            || IS_CSR_REGNUM (regnum)
1050
            || IS_CR_REGNUM (regnum)
1051
            || IS_CCR_REGNUM (regnum));
1052
 
1053
  /* All registers should be saved and restored, except for the raw
1054
     CSR's.
1055
 
1056
     This is probably right if the coprocessor is something like a
1057
     floating-point unit, but would be wrong if the coprocessor is
1058
     something that does I/O, where register accesses actually cause
1059
     externally-visible actions.  But I get the impression that the
1060
     coprocessor isn't supposed to do things like that --- you'd use a
1061
     hardware engine, perhaps.  */
1062
  else if (group == save_reggroup || group == restore_reggroup)
1063
    return (IS_GPR_REGNUM (regnum)
1064
            || IS_CSR_REGNUM (regnum)
1065
            || IS_CR_REGNUM (regnum)
1066
            || IS_CCR_REGNUM (regnum));
1067
 
1068
  else if (group == mep_csr_reggroup)
1069
    return IS_CSR_REGNUM (regnum);
1070
  else if (group == mep_cr_reggroup)
1071
    return IS_CR_REGNUM (regnum);
1072
  else if (group == mep_ccr_reggroup)
1073
    return IS_CCR_REGNUM (regnum);
1074
  else
1075
    return 0;
1076
}
1077
 
1078
 
1079
static struct type *
1080
mep_register_type (struct gdbarch *gdbarch, int reg_nr)
1081
{
1082
  /* Coprocessor general-purpose registers may be either 32 or 64 bits
1083
     long.  So for them, the raw registers are always 64 bits long (to
1084
     keep the 'g' packet format fixed), and the pseudoregisters vary
1085
     in length.  */
1086
  if (IS_RAW_CR_REGNUM (reg_nr))
1087
    return builtin_type_uint64;
1088
 
1089
  /* Since GDB doesn't allow registers to change type, we have two
1090
     banks of pseudoregisters for the coprocessor general-purpose
1091
     registers: one that gives a 32-bit view, and one that gives a
1092
     64-bit view.  We hide or show one or the other depending on the
1093
     current module.  */
1094
  if (IS_CR_REGNUM (reg_nr))
1095
    {
1096
      int size = mep_pseudo_cr_size (reg_nr);
1097
      if (size == 32)
1098
        {
1099
          if (mep_pseudo_cr_is_float (reg_nr))
1100
            return builtin_type_float;
1101
          else
1102
            return builtin_type_uint32;
1103
        }
1104
      else if (size == 64)
1105
        {
1106
          if (mep_pseudo_cr_is_float (reg_nr))
1107
            return builtin_type_double;
1108
          else
1109
            return builtin_type_uint64;
1110
        }
1111
      else
1112
        gdb_assert (0);
1113
    }
1114
 
1115
  /* All other registers are 32 bits long.  */
1116
  else
1117
    return builtin_type_uint32;
1118
}
1119
 
1120
 
1121
static CORE_ADDR
1122
mep_read_pc (struct regcache *regcache)
1123
{
1124
  ULONGEST pc;
1125
  regcache_cooked_read_unsigned (regcache, MEP_PC_REGNUM, &pc);
1126
  return pc;
1127
}
1128
 
1129
static void
1130
mep_write_pc (struct regcache *regcache, CORE_ADDR pc)
1131
{
1132
  regcache_cooked_write_unsigned (regcache, MEP_PC_REGNUM, pc);
1133
}
1134
 
1135
 
1136
static void
1137
mep_pseudo_cr32_read (struct gdbarch *gdbarch,
1138
                      struct regcache *regcache,
1139
                      int cookednum,
1140
                      void *buf)
1141
{
1142
  /* Read the raw register into a 64-bit buffer, and then return the
1143
     appropriate end of that buffer.  */
1144
  int rawnum = mep_pseudo_to_raw[cookednum];
1145
  char buf64[8];
1146
 
1147
  gdb_assert (TYPE_LENGTH (register_type (gdbarch, rawnum)) == sizeof (buf64));
1148
  gdb_assert (TYPE_LENGTH (register_type (gdbarch, cookednum)) == 4);
1149
  regcache_raw_read (regcache, rawnum, buf64);
1150
  /* Slow, but legible.  */
1151
  store_unsigned_integer (buf, 4, extract_unsigned_integer (buf64, 8));
1152
}
1153
 
1154
 
1155
static void
1156
mep_pseudo_cr64_read (struct gdbarch *gdbarch,
1157
                      struct regcache *regcache,
1158
                      int cookednum,
1159
                      void *buf)
1160
{
1161
  regcache_raw_read (regcache, mep_pseudo_to_raw[cookednum], buf);
1162
}
1163
 
1164
 
1165
static void
1166
mep_pseudo_register_read (struct gdbarch *gdbarch,
1167
                          struct regcache *regcache,
1168
                          int cookednum,
1169
                          gdb_byte *buf)
1170
{
1171
  if (IS_CSR_REGNUM (cookednum)
1172
      || IS_CCR_REGNUM (cookednum))
1173
    regcache_raw_read (regcache, mep_pseudo_to_raw[cookednum], buf);
1174
  else if (IS_CR32_REGNUM (cookednum)
1175
           || IS_FP_CR32_REGNUM (cookednum))
1176
    mep_pseudo_cr32_read (gdbarch, regcache, cookednum, buf);
1177
  else if (IS_CR64_REGNUM (cookednum)
1178
           || IS_FP_CR64_REGNUM (cookednum))
1179
    mep_pseudo_cr64_read (gdbarch, regcache, cookednum, buf);
1180
  else
1181
    gdb_assert (0);
1182
}
1183
 
1184
 
1185
static void
1186
mep_pseudo_csr_write (struct gdbarch *gdbarch,
1187
                      struct regcache *regcache,
1188
                      int cookednum,
1189
                      const void *buf)
1190
{
1191
  int size = register_size (gdbarch, cookednum);
1192
  struct mep_csr_register *r
1193
    = &mep_csr_registers[cookednum - MEP_FIRST_CSR_REGNUM];
1194
 
1195
  if (r->writeable_bits == 0)
1196
    /* A completely read-only register; avoid the read-modify-
1197
       write cycle, and juts ignore the entire write.  */
1198
    ;
1199
  else
1200
    {
1201
      /* A partially writeable register; do a read-modify-write cycle.  */
1202
      ULONGEST old_bits;
1203
      ULONGEST new_bits;
1204
      ULONGEST mixed_bits;
1205
 
1206
      regcache_raw_read_unsigned (regcache, r->raw, &old_bits);
1207
      new_bits = extract_unsigned_integer (buf, size);
1208
      mixed_bits = ((r->writeable_bits & new_bits)
1209
                    | (~r->writeable_bits & old_bits));
1210
      regcache_raw_write_unsigned (regcache, r->raw, mixed_bits);
1211
    }
1212
}
1213
 
1214
 
1215
static void
1216
mep_pseudo_cr32_write (struct gdbarch *gdbarch,
1217
                       struct regcache *regcache,
1218
                       int cookednum,
1219
                       const void *buf)
1220
{
1221
  /* Expand the 32-bit value into a 64-bit value, and write that to
1222
     the pseudoregister.  */
1223
  int rawnum = mep_pseudo_to_raw[cookednum];
1224
  char buf64[8];
1225
 
1226
  gdb_assert (TYPE_LENGTH (register_type (gdbarch, rawnum)) == sizeof (buf64));
1227
  gdb_assert (TYPE_LENGTH (register_type (gdbarch, cookednum)) == 4);
1228
  /* Slow, but legible.  */
1229
  store_unsigned_integer (buf64, 8, extract_unsigned_integer (buf, 4));
1230
  regcache_raw_write (regcache, rawnum, buf64);
1231
}
1232
 
1233
 
1234
static void
1235
mep_pseudo_cr64_write (struct gdbarch *gdbarch,
1236
                     struct regcache *regcache,
1237
                     int cookednum,
1238
                     const void *buf)
1239
{
1240
  regcache_raw_write (regcache, mep_pseudo_to_raw[cookednum], buf);
1241
}
1242
 
1243
 
1244
static void
1245
mep_pseudo_register_write (struct gdbarch *gdbarch,
1246
                           struct regcache *regcache,
1247
                           int cookednum,
1248
                           const gdb_byte *buf)
1249
{
1250
  if (IS_CSR_REGNUM (cookednum))
1251
    mep_pseudo_csr_write (gdbarch, regcache, cookednum, buf);
1252
  else if (IS_CR32_REGNUM (cookednum)
1253
           || IS_FP_CR32_REGNUM (cookednum))
1254
    mep_pseudo_cr32_write (gdbarch, regcache, cookednum, buf);
1255
  else if (IS_CR64_REGNUM (cookednum)
1256
           || IS_FP_CR64_REGNUM (cookednum))
1257
    mep_pseudo_cr64_write (gdbarch, regcache, cookednum, buf);
1258
  else if (IS_CCR_REGNUM (cookednum))
1259
    regcache_raw_write (regcache, mep_pseudo_to_raw[cookednum], buf);
1260
  else
1261
    gdb_assert (0);
1262
}
1263
 
1264
 
1265
 
1266
/* Disassembly.  */
1267
 
1268
/* The mep disassembler needs to know about the section in order to
1269
   work correctly. */
1270
int
1271
mep_gdb_print_insn (bfd_vma pc, disassemble_info * info)
1272
{
1273
  struct obj_section * s = find_pc_section (pc);
1274
 
1275
  if (s)
1276
    {
1277
      /* The libopcodes disassembly code uses the section to find the
1278
         BFD, the BFD to find the ELF header, the ELF header to find
1279
         the me_module index, and the me_module index to select the
1280
         right instructions to print.  */
1281
      info->section = s->the_bfd_section;
1282
      info->arch = bfd_arch_mep;
1283
 
1284
      return print_insn_mep (pc, info);
1285
    }
1286
 
1287
  return 0;
1288
}
1289
 
1290
 
1291
/* Prologue analysis.  */
1292
 
1293
 
1294
/* The MeP has two classes of instructions: "core" instructions, which
1295
   are pretty normal RISC chip stuff, and "coprocessor" instructions,
1296
   which are mostly concerned with moving data in and out of
1297
   coprocessor registers, and branching on coprocessor condition
1298
   codes.  There's space in the instruction set for custom coprocessor
1299
   instructions, too.
1300
 
1301
   Instructions can be 16 or 32 bits long; the top two bits of the
1302
   first byte indicate the length.  The coprocessor instructions are
1303
   mixed in with the core instructions, and there's no easy way to
1304
   distinguish them; you have to completely decode them to tell one
1305
   from the other.
1306
 
1307
   The MeP also supports a "VLIW" operation mode, where instructions
1308
   always occur in fixed-width bundles.  The bundles are either 32
1309
   bits or 64 bits long, depending on a fixed configuration flag.  You
1310
   decode the first part of the bundle as normal; if it's a core
1311
   instruction, and there's any space left in the bundle, the
1312
   remainder of the bundle is a coprocessor instruction, which will
1313
   execute in parallel with the core instruction.  If the first part
1314
   of the bundle is a coprocessor instruction, it occupies the entire
1315
   bundle.
1316
 
1317
   So, here are all the cases:
1318
 
1319
   - 32-bit VLIW mode:
1320
     Every bundle is four bytes long, and naturally aligned, and can hold
1321
     one or two instructions:
1322
     - 16-bit core instruction; 16-bit coprocessor instruction
1323
       These execute in parallel.
1324
     - 32-bit core instruction
1325
     - 32-bit coprocessor instruction
1326
 
1327
   - 64-bit VLIW mode:
1328
     Every bundle is eight bytes long, and naturally aligned, and can hold
1329
     one or two instructions:
1330
     - 16-bit core instruction; 48-bit (!) coprocessor instruction
1331
       These execute in parallel.
1332
     - 32-bit core instruction; 32-bit coprocessor instruction
1333
       These execute in parallel.
1334
     - 64-bit coprocessor instruction
1335
 
1336
   Now, the MeP manual doesn't define any 48- or 64-bit coprocessor
1337
   instruction, so I don't really know what's up there; perhaps these
1338
   are always the user-defined coprocessor instructions.  */
1339
 
1340
 
1341
/* Return non-zero if PC is in a VLIW code section, zero
1342
   otherwise.  */
1343
static int
1344
mep_pc_in_vliw_section (CORE_ADDR pc)
1345
{
1346
  struct obj_section *s = find_pc_section (pc);
1347
  if (s)
1348
    return (s->the_bfd_section->flags & SEC_MEP_VLIW);
1349
  return 0;
1350
}
1351
 
1352
 
1353
/* Set *INSN to the next core instruction at PC, and return the
1354
   address of the next instruction.
1355
 
1356
   The MeP instruction encoding is endian-dependent.  16- and 32-bit
1357
   instructions are encoded as one or two two-byte parts, and each
1358
   part is byte-swapped independently.  Thus:
1359
 
1360
      void
1361
      foo (void)
1362
      {
1363
        asm ("movu $1, 0x123456");
1364
        asm ("sb $1,0x5678($2)");
1365
        asm ("clip $1, 19");
1366
      }
1367
 
1368
   compiles to this big-endian code:
1369
 
1370
       0:       d1 56 12 34     movu $1,0x123456
1371
       4:       c1 28 56 78     sb $1,22136($2)
1372
       8:       f1 01 10 98     clip $1,0x13
1373
       c:       70 02           ret
1374
 
1375
   and this little-endian code:
1376
 
1377
       0:       56 d1 34 12     movu $1,0x123456
1378
       4:       28 c1 78 56     sb $1,22136($2)
1379
       8:       01 f1 98 10     clip $1,0x13
1380
       c:       02 70           ret
1381
 
1382
   Instructions are returned in *INSN in an endian-independent form: a
1383
   given instruction always appears in *INSN the same way, regardless
1384
   of whether the instruction stream is big-endian or little-endian.
1385
 
1386
   *INSN's most significant 16 bits are the first (i.e., at lower
1387
   addresses) 16 bit part of the instruction.  Its least significant
1388
   16 bits are the second (i.e., higher-addressed) 16 bit part of the
1389
   instruction, or zero for a 16-bit instruction.  Both 16-bit parts
1390
   are fetched using the current endianness.
1391
 
1392
   So, the *INSN values for the instruction sequence above would be
1393
   the following, in either endianness:
1394
 
1395
       0xd1561234       movu $1,0x123456
1396
       0xc1285678       sb $1,22136($2)
1397
       0xf1011098       clip $1,0x13
1398
       0x70020000       ret
1399
 
1400
   (In a sense, it would be more natural to return 16-bit instructions
1401
   in the least significant 16 bits of *INSN, but that would be
1402
   ambiguous.  In order to tell whether you're looking at a 16- or a
1403
   32-bit instruction, you have to consult the major opcode field ---
1404
   the most significant four bits of the instruction's first 16-bit
1405
   part.  But if we put 16-bit instructions at the least significant
1406
   end of *INSN, then you don't know where to find the major opcode
1407
   field until you know if it's a 16- or a 32-bit instruction ---
1408
   which is where we started.)
1409
 
1410
   If PC points to a core / coprocessor bundle in a VLIW section, set
1411
   *INSN to the core instruction, and return the address of the next
1412
   bundle.  This has the effect of skipping the bundled coprocessor
1413
   instruction.  That's okay, since coprocessor instructions aren't
1414
   significant to prologue analysis --- for the time being,
1415
   anyway.  */
1416
 
1417
static CORE_ADDR
1418
mep_get_insn (CORE_ADDR pc, long *insn)
1419
{
1420
  int pc_in_vliw_section;
1421
  int vliw_mode;
1422
  int insn_len;
1423
  char buf[2];
1424
 
1425
  *insn = 0;
1426
 
1427
  /* Are we in a VLIW section?  */
1428
  pc_in_vliw_section = mep_pc_in_vliw_section (pc);
1429
  if (pc_in_vliw_section)
1430
    {
1431
      /* Yes, find out which bundle size.  */
1432
      vliw_mode = current_options () & (MEP_OPT_VL32 | MEP_OPT_VL64);
1433
 
1434
      /* If PC is in a VLIW section, but the current core doesn't say
1435
         that it supports either VLIW mode, then we don't have enough
1436
         information to parse the instruction stream it contains.
1437
         Since the "undifferentiated" standard core doesn't have
1438
         either VLIW mode bit set, this could happen.
1439
 
1440
         But it shouldn't be an error to (say) set a breakpoint in a
1441
         VLIW section, if you know you'll never reach it.  (Perhaps
1442
         you have a script that sets a bunch of standard breakpoints.)
1443
 
1444
         So we'll just return zero here, and hope for the best.  */
1445
      if (! (vliw_mode & (MEP_OPT_VL32 | MEP_OPT_VL64)))
1446
        return 0;
1447
 
1448
      /* If both VL32 and VL64 are set, that's bogus, too.  */
1449
      if (vliw_mode == (MEP_OPT_VL32 | MEP_OPT_VL64))
1450
        return 0;
1451
    }
1452
  else
1453
    vliw_mode = 0;
1454
 
1455
  read_memory (pc, buf, sizeof (buf));
1456
  *insn = extract_unsigned_integer (buf, 2) << 16;
1457
 
1458
  /* The major opcode --- the top four bits of the first 16-bit
1459
     part --- indicates whether this instruction is 16 or 32 bits
1460
     long.  All 32-bit instructions have a major opcode whose top
1461
     two bits are 11; all the rest are 16-bit instructions.  */
1462
  if ((*insn & 0xc0000000) == 0xc0000000)
1463
    {
1464
      /* Fetch the second 16-bit part of the instruction.  */
1465
      read_memory (pc + 2, buf, sizeof (buf));
1466
      *insn = *insn | extract_unsigned_integer (buf, 2);
1467
    }
1468
 
1469
  /* If we're in VLIW code, then the VLIW width determines the address
1470
     of the next instruction.  */
1471
  if (vliw_mode)
1472
    {
1473
      /* In 32-bit VLIW code, all bundles are 32 bits long.  We ignore the
1474
         coprocessor half of a core / copro bundle.  */
1475
      if (vliw_mode == MEP_OPT_VL32)
1476
        insn_len = 4;
1477
 
1478
      /* In 64-bit VLIW code, all bundles are 64 bits long.  We ignore the
1479
         coprocessor half of a core / copro bundle.  */
1480
      else if (vliw_mode == MEP_OPT_VL64)
1481
        insn_len = 8;
1482
 
1483
      /* We'd better be in either core, 32-bit VLIW, or 64-bit VLIW mode.  */
1484
      else
1485
        gdb_assert (0);
1486
    }
1487
 
1488
  /* Otherwise, the top two bits of the major opcode are (again) what
1489
     we need to check.  */
1490
  else if ((*insn & 0xc0000000) == 0xc0000000)
1491
    insn_len = 4;
1492
  else
1493
    insn_len = 2;
1494
 
1495
  return pc + insn_len;
1496
}
1497
 
1498
 
1499
/* Sign-extend the LEN-bit value N.  */
1500
#define SEXT(n, len) ((((int) (n)) ^ (1 << ((len) - 1))) - (1 << ((len) - 1)))
1501
 
1502
/* Return the LEN-bit field at POS from I.  */
1503
#define FIELD(i, pos, len) (((i) >> (pos)) & ((1 << (len)) - 1))
1504
 
1505
/* Like FIELD, but sign-extend the field's value.  */
1506
#define SFIELD(i, pos, len) (SEXT (FIELD ((i), (pos), (len)), (len)))
1507
 
1508
 
1509
/* Macros for decoding instructions.
1510
 
1511
   Remember that 16-bit instructions are placed in bits 16..31 of i,
1512
   not at the least significant end; this means that the major opcode
1513
   field is always in the same place, regardless of the width of the
1514
   instruction.  As a reminder of this, we show the lower 16 bits of a
1515
   16-bit instruction as xxxx_xxxx_xxxx_xxxx.  */
1516
 
1517
/* SB Rn,(Rm)                 0000_nnnn_mmmm_1000 */
1518
/* SH Rn,(Rm)                 0000_nnnn_mmmm_1001 */
1519
/* SW Rn,(Rm)                 0000_nnnn_mmmm_1010 */
1520
 
1521
/* SW Rn,disp16(Rm)           1100_nnnn_mmmm_1010 dddd_dddd_dddd_dddd */
1522
#define IS_SW(i)              (((i) & 0xf00f0000) == 0xc00a0000)
1523
/* SB Rn,disp16(Rm)           1100_nnnn_mmmm_1000 dddd_dddd_dddd_dddd */
1524
#define IS_SB(i)              (((i) & 0xf00f0000) == 0xc0080000)
1525
/* SH Rn,disp16(Rm)           1100_nnnn_mmmm_1001 dddd_dddd_dddd_dddd */
1526
#define IS_SH(i)              (((i) & 0xf00f0000) == 0xc0090000)
1527
#define SWBH_32_BASE(i)       (FIELD (i, 20, 4))
1528
#define SWBH_32_SOURCE(i)     (FIELD (i, 24, 4))
1529
#define SWBH_32_OFFSET(i)     (SFIELD (i, 0, 16))
1530
 
1531
/* SW Rn,disp7.align4(SP)     0100_nnnn_0ddd_dd10 xxxx_xxxx_xxxx_xxxx */
1532
#define IS_SW_IMMD(i)         (((i) & 0xf0830000) == 0x40020000)
1533
#define SW_IMMD_SOURCE(i)     (FIELD (i, 24, 4))
1534
#define SW_IMMD_OFFSET(i)     (FIELD (i, 18, 5) << 2)
1535
 
1536
/* SW Rn,(Rm)                 0000_nnnn_mmmm_1010 xxxx_xxxx_xxxx_xxxx */
1537
#define IS_SW_REG(i)          (((i) & 0xf00f0000) == 0x000a0000)
1538
#define SW_REG_SOURCE(i)      (FIELD (i, 24, 4))
1539
#define SW_REG_BASE(i)        (FIELD (i, 20, 4))
1540
 
1541
/* ADD3 Rl,Rn,Rm              1001_nnnn_mmmm_llll xxxx_xxxx_xxxx_xxxx */
1542
#define IS_ADD3_16_REG(i)     (((i) & 0xf0000000) == 0x90000000)
1543
#define ADD3_16_REG_SRC1(i)   (FIELD (i, 20, 4))               /* n */
1544
#define ADD3_16_REG_SRC2(i)   (FIELD (i, 24, 4))               /* m */
1545
 
1546
/* ADD3 Rn,Rm,imm16           1100_nnnn_mmmm_0000 iiii_iiii_iiii_iiii */
1547
#define IS_ADD3_32(i)         (((i) & 0xf00f0000) == 0xc0000000)
1548
#define ADD3_32_TARGET(i)     (FIELD (i, 24, 4))
1549
#define ADD3_32_SOURCE(i)     (FIELD (i, 20, 4))
1550
#define ADD3_32_OFFSET(i)     (SFIELD (i, 0, 16))
1551
 
1552
/* ADD3 Rn,SP,imm7.align4     0100_nnnn_0iii_ii00 xxxx_xxxx_xxxx_xxxx */
1553
#define IS_ADD3_16(i)         (((i) & 0xf0830000) == 0x40000000)
1554
#define ADD3_16_TARGET(i)     (FIELD (i, 24, 4))
1555
#define ADD3_16_OFFSET(i)     (FIELD (i, 18, 5) << 2)
1556
 
1557
/* ADD Rn,imm6                0110_nnnn_iiii_ii00 xxxx_xxxx_xxxx_xxxx */
1558
#define IS_ADD(i)             (((i) & 0xf0030000) == 0x60000000)
1559
#define ADD_TARGET(i)         (FIELD (i, 24, 4))
1560
#define ADD_OFFSET(i)         (SFIELD (i, 18, 6))
1561
 
1562
/* LDC Rn,imm5                0111_nnnn_iiii_101I xxxx_xxxx_xxxx_xxxx
1563
                              imm5 = I||i[7:4] */
1564
#define IS_LDC(i)             (((i) & 0xf00e0000) == 0x700a0000)
1565
#define LDC_IMM(i)            ((FIELD (i, 16, 1) << 4) | FIELD (i, 20, 4))
1566
#define LDC_TARGET(i)         (FIELD (i, 24, 4))
1567
 
1568
/* LW Rn,disp16(Rm)           1100_nnnn_mmmm_1110 dddd_dddd_dddd_dddd  */
1569
#define IS_LW(i)              (((i) & 0xf00f0000) == 0xc00e0000)
1570
#define LW_TARGET(i)          (FIELD (i, 24, 4))
1571
#define LW_BASE(i)            (FIELD (i, 20, 4))
1572
#define LW_OFFSET(i)          (SFIELD (i, 0, 16))
1573
 
1574
/* MOV Rn,Rm                  0000_nnnn_mmmm_0000 xxxx_xxxx_xxxx_xxxx */
1575
#define IS_MOV(i)             (((i) & 0xf00f0000) == 0x00000000)
1576
#define MOV_TARGET(i)         (FIELD (i, 24, 4))
1577
#define MOV_SOURCE(i)         (FIELD (i, 20, 4))
1578
 
1579
/* BRA disp12.align2          1011_dddd_dddd_ddd0 xxxx_xxxx_xxxx_xxxx */
1580
#define IS_BRA(i)             (((i) & 0xf0010000) == 0xb0000000)
1581
#define BRA_DISP(i)           (SFIELD (i, 17, 11) << 1)
1582
 
1583
 
1584
/* This structure holds the results of a prologue analysis.  */
1585
struct mep_prologue
1586
{
1587
  /* The offset from the frame base to the stack pointer --- always
1588
     zero or negative.
1589
 
1590
     Calling this a "size" is a bit misleading, but given that the
1591
     stack grows downwards, using offsets for everything keeps one
1592
     from going completely sign-crazy: you never change anything's
1593
     sign for an ADD instruction; always change the second operand's
1594
     sign for a SUB instruction; and everything takes care of
1595
     itself.  */
1596
  int frame_size;
1597
 
1598
  /* Non-zero if this function has initialized the frame pointer from
1599
     the stack pointer, zero otherwise.  */
1600
  int has_frame_ptr;
1601
 
1602
  /* If has_frame_ptr is non-zero, this is the offset from the frame
1603
     base to where the frame pointer points.  This is always zero or
1604
     negative.  */
1605
  int frame_ptr_offset;
1606
 
1607
  /* The address of the first instruction at which the frame has been
1608
     set up and the arguments are where the debug info says they are
1609
     --- as best as we can tell.  */
1610
  CORE_ADDR prologue_end;
1611
 
1612
  /* reg_offset[R] is the offset from the CFA at which register R is
1613
     saved, or 1 if register R has not been saved.  (Real values are
1614
     always zero or negative.)  */
1615
  int reg_offset[MEP_NUM_REGS];
1616
};
1617
 
1618
/* Return non-zero if VALUE is an incoming argument register.  */
1619
 
1620
static int
1621
is_arg_reg (pv_t value)
1622
{
1623
  return (value.kind == pvk_register
1624
          && MEP_R1_REGNUM <= value.reg && value.reg <= MEP_R4_REGNUM
1625
          && value.k == 0);
1626
}
1627
 
1628
/* Return non-zero if a store of REG's current value VALUE to ADDR is
1629
   probably spilling an argument register to its stack slot in STACK.
1630
   Such instructions should be included in the prologue, if possible.
1631
 
1632
   The store is a spill if:
1633
   - the value being stored is REG's original value;
1634
   - the value has not already been stored somewhere in STACK; and
1635
   - ADDR is a stack slot's address (e.g., relative to the original
1636
     value of the SP).  */
1637
static int
1638
is_arg_spill (pv_t value, pv_t addr, struct pv_area *stack)
1639
{
1640
  return (is_arg_reg (value)
1641
          && pv_is_register (addr, MEP_SP_REGNUM)
1642
          && ! pv_area_find_reg (stack, current_gdbarch, value.reg, 0));
1643
}
1644
 
1645
 
1646
/* Function for finding saved registers in a 'struct pv_area'; we pass
1647
   this to pv_area_scan.
1648
 
1649
   If VALUE is a saved register, ADDR says it was saved at a constant
1650
   offset from the frame base, and SIZE indicates that the whole
1651
   register was saved, record its offset in RESULT_UNTYPED.  */
1652
static void
1653
check_for_saved (void *result_untyped, pv_t addr, CORE_ADDR size, pv_t value)
1654
{
1655
  struct mep_prologue *result = (struct mep_prologue *) result_untyped;
1656
 
1657
  if (value.kind == pvk_register
1658
      && value.k == 0
1659
      && pv_is_register (addr, MEP_SP_REGNUM)
1660
      && size == register_size (current_gdbarch, value.reg))
1661
    result->reg_offset[value.reg] = addr.k;
1662
}
1663
 
1664
 
1665
/* Analyze a prologue starting at START_PC, going no further than
1666
   LIMIT_PC.  Fill in RESULT as appropriate.  */
1667
static void
1668
mep_analyze_prologue (CORE_ADDR start_pc, CORE_ADDR limit_pc,
1669
                      struct mep_prologue *result)
1670
{
1671
  CORE_ADDR pc;
1672
  unsigned long insn;
1673
  int rn;
1674
  int found_lp = 0;
1675
  pv_t reg[MEP_NUM_REGS];
1676
  struct pv_area *stack;
1677
  struct cleanup *back_to;
1678
  CORE_ADDR after_last_frame_setup_insn = start_pc;
1679
 
1680
  memset (result, 0, sizeof (*result));
1681
 
1682
  for (rn = 0; rn < MEP_NUM_REGS; rn++)
1683
    {
1684
      reg[rn] = pv_register (rn, 0);
1685
      result->reg_offset[rn] = 1;
1686
    }
1687
 
1688
  stack = make_pv_area (MEP_SP_REGNUM);
1689
  back_to = make_cleanup_free_pv_area (stack);
1690
 
1691
  pc = start_pc;
1692
  while (pc < limit_pc)
1693
    {
1694
      CORE_ADDR next_pc;
1695
      pv_t pre_insn_fp, pre_insn_sp;
1696
 
1697
      next_pc = mep_get_insn (pc, &insn);
1698
 
1699
      /* A zero return from mep_get_insn means that either we weren't
1700
         able to read the instruction from memory, or that we don't
1701
         have enough information to be able to reliably decode it.  So
1702
         we'll store here and hope for the best.  */
1703
      if (! next_pc)
1704
        break;
1705
 
1706
      /* Note the current values of the SP and FP, so we can tell if
1707
         this instruction changed them, below.  */
1708
      pre_insn_fp = reg[MEP_FP_REGNUM];
1709
      pre_insn_sp = reg[MEP_SP_REGNUM];
1710
 
1711
      if (IS_ADD (insn))
1712
        {
1713
          int rn = ADD_TARGET (insn);
1714
          CORE_ADDR imm6 = ADD_OFFSET (insn);
1715
 
1716
          reg[rn] = pv_add_constant (reg[rn], imm6);
1717
        }
1718
      else if (IS_ADD3_16 (insn))
1719
        {
1720
          int rn = ADD3_16_TARGET (insn);
1721
          int imm7 = ADD3_16_OFFSET (insn);
1722
 
1723
          reg[rn] = pv_add_constant (reg[MEP_SP_REGNUM], imm7);
1724
        }
1725
      else if (IS_ADD3_32 (insn))
1726
        {
1727
          int rn = ADD3_32_TARGET (insn);
1728
          int rm = ADD3_32_SOURCE (insn);
1729
          int imm16 = ADD3_32_OFFSET (insn);
1730
 
1731
          reg[rn] = pv_add_constant (reg[rm], imm16);
1732
        }
1733
      else if (IS_SW_REG (insn))
1734
        {
1735
          int rn = SW_REG_SOURCE (insn);
1736
          int rm = SW_REG_BASE (insn);
1737
 
1738
          /* If simulating this store would require us to forget
1739
             everything we know about the stack frame in the name of
1740
             accuracy, it would be better to just quit now.  */
1741
          if (pv_area_store_would_trash (stack, reg[rm]))
1742
            break;
1743
 
1744
          if (is_arg_spill (reg[rn], reg[rm], stack))
1745
            after_last_frame_setup_insn = next_pc;
1746
 
1747
          pv_area_store (stack, reg[rm], 4, reg[rn]);
1748
        }
1749
      else if (IS_SW_IMMD (insn))
1750
        {
1751
          int rn = SW_IMMD_SOURCE (insn);
1752
          int offset = SW_IMMD_OFFSET (insn);
1753
          pv_t addr = pv_add_constant (reg[MEP_SP_REGNUM], offset);
1754
 
1755
          /* If simulating this store would require us to forget
1756
             everything we know about the stack frame in the name of
1757
             accuracy, it would be better to just quit now.  */
1758
          if (pv_area_store_would_trash (stack, addr))
1759
            break;
1760
 
1761
          if (is_arg_spill (reg[rn], addr, stack))
1762
            after_last_frame_setup_insn = next_pc;
1763
 
1764
          pv_area_store (stack, addr, 4, reg[rn]);
1765
        }
1766
      else if (IS_MOV (insn))
1767
        {
1768
          int rn = MOV_TARGET (insn);
1769
          int rm = MOV_SOURCE (insn);
1770
 
1771
          reg[rn] = reg[rm];
1772
 
1773
          if (pv_is_register (reg[rm], rm) && is_arg_reg (reg[rm]))
1774
            after_last_frame_setup_insn = next_pc;
1775
        }
1776
      else if (IS_SB (insn) || IS_SH (insn) || IS_SW (insn))
1777
        {
1778
          int rn = SWBH_32_SOURCE (insn);
1779
          int rm = SWBH_32_BASE (insn);
1780
          int disp = SWBH_32_OFFSET (insn);
1781
          int size = (IS_SB (insn) ? 1
1782
                      : IS_SH (insn) ? 2
1783
                      : IS_SW (insn) ? 4
1784
                      : (gdb_assert (0), 1));
1785
          pv_t addr = pv_add_constant (reg[rm], disp);
1786
 
1787
          if (pv_area_store_would_trash (stack, addr))
1788
            break;
1789
 
1790
          if (is_arg_spill (reg[rn], addr, stack))
1791
            after_last_frame_setup_insn = next_pc;
1792
 
1793
          pv_area_store (stack, addr, size, reg[rn]);
1794
        }
1795
      else if (IS_LDC (insn))
1796
        {
1797
          int rn = LDC_TARGET (insn);
1798
          int cr = LDC_IMM (insn) + MEP_FIRST_CSR_REGNUM;
1799
 
1800
          reg[rn] = reg[cr];
1801
        }
1802
      else if (IS_LW (insn))
1803
        {
1804
          int rn = LW_TARGET (insn);
1805
          int rm = LW_BASE (insn);
1806
          int offset = LW_OFFSET (insn);
1807
          pv_t addr = pv_add_constant (reg[rm], offset);
1808
 
1809
          reg[rn] = pv_area_fetch (stack, addr, 4);
1810
        }
1811
      else if (IS_BRA (insn) && BRA_DISP (insn) > 0)
1812
        {
1813
          /* When a loop appears as the first statement of a function
1814
             body, gcc 4.x will use a BRA instruction to branch to the
1815
             loop condition checking code.  This BRA instruction is
1816
             marked as part of the prologue.  We therefore set next_pc
1817
             to this branch target and also stop the prologue scan.
1818
             The instructions at and beyond the branch target should
1819
             no longer be associated with the prologue.
1820
 
1821
             Note that we only consider forward branches here.  We
1822
             presume that a forward branch is being used to skip over
1823
             a loop body.
1824
 
1825
             A backwards branch is covered by the default case below.
1826
             If we were to encounter a backwards branch, that would
1827
             most likely mean that we've scanned through a loop body.
1828
             We definitely want to stop the prologue scan when this
1829
             happens and that is precisely what is done by the default
1830
             case below.  */
1831
          next_pc = pc + BRA_DISP (insn);
1832
          after_last_frame_setup_insn = next_pc;
1833
          break;
1834
        }
1835
      else
1836
        /* We've hit some instruction we don't know how to simulate.
1837
           Strictly speaking, we should set every value we're
1838
           tracking to "unknown".  But we'll be optimistic, assume
1839
           that we have enough information already, and stop
1840
           analysis here.  */
1841
        break;
1842
 
1843
      /* If this instruction changed the FP or decreased the SP (i.e.,
1844
         allocated more stack space), then this may be a good place to
1845
         declare the prologue finished.  However, there are some
1846
         exceptions:
1847
 
1848
         - If the instruction just changed the FP back to its original
1849
           value, then that's probably a restore instruction.  The
1850
           prologue should definitely end before that.
1851
 
1852
         - If the instruction increased the value of the SP (that is,
1853
           shrunk the frame), then it's probably part of a frame
1854
           teardown sequence, and the prologue should end before that.  */
1855
 
1856
      if (! pv_is_identical (reg[MEP_FP_REGNUM], pre_insn_fp))
1857
        {
1858
          if (! pv_is_register_k (reg[MEP_FP_REGNUM], MEP_FP_REGNUM, 0))
1859
            after_last_frame_setup_insn = next_pc;
1860
        }
1861
      else if (! pv_is_identical (reg[MEP_SP_REGNUM], pre_insn_sp))
1862
        {
1863
          /* The comparison of constants looks odd, there, because .k
1864
             is unsigned.  All it really means is that the new value
1865
             is lower than it was before the instruction.  */
1866
          if (pv_is_register (pre_insn_sp, MEP_SP_REGNUM)
1867
              && pv_is_register (reg[MEP_SP_REGNUM], MEP_SP_REGNUM)
1868
              && ((pre_insn_sp.k - reg[MEP_SP_REGNUM].k)
1869
                  < (reg[MEP_SP_REGNUM].k - pre_insn_sp.k)))
1870
            after_last_frame_setup_insn = next_pc;
1871
        }
1872
 
1873
      pc = next_pc;
1874
    }
1875
 
1876
  /* Is the frame size (offset, really) a known constant?  */
1877
  if (pv_is_register (reg[MEP_SP_REGNUM], MEP_SP_REGNUM))
1878
    result->frame_size = reg[MEP_SP_REGNUM].k;
1879
 
1880
  /* Was the frame pointer initialized?  */
1881
  if (pv_is_register (reg[MEP_FP_REGNUM], MEP_SP_REGNUM))
1882
    {
1883
      result->has_frame_ptr = 1;
1884
      result->frame_ptr_offset = reg[MEP_FP_REGNUM].k;
1885
    }
1886
 
1887
  /* Record where all the registers were saved.  */
1888
  pv_area_scan (stack, check_for_saved, (void *) result);
1889
 
1890
  result->prologue_end = after_last_frame_setup_insn;
1891
 
1892
  do_cleanups (back_to);
1893
}
1894
 
1895
 
1896
static CORE_ADDR
1897
mep_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
1898
{
1899
  char *name;
1900
  CORE_ADDR func_addr, func_end;
1901
  struct mep_prologue p;
1902
 
1903
  /* Try to find the extent of the function that contains PC.  */
1904
  if (! find_pc_partial_function (pc, &name, &func_addr, &func_end))
1905
    return pc;
1906
 
1907
  mep_analyze_prologue (pc, func_end, &p);
1908
  return p.prologue_end;
1909
}
1910
 
1911
 
1912
 
1913
/* Breakpoints.  */
1914
 
1915
static const unsigned char *
1916
mep_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR * pcptr, int *lenptr)
1917
{
1918
  static unsigned char breakpoint[] = { 0x70, 0x32 };
1919
  *lenptr = sizeof (breakpoint);
1920
  return breakpoint;
1921
}
1922
 
1923
 
1924
 
1925
/* Frames and frame unwinding.  */
1926
 
1927
 
1928
static struct mep_prologue *
1929
mep_analyze_frame_prologue (struct frame_info *next_frame,
1930
                            void **this_prologue_cache)
1931
{
1932
  if (! *this_prologue_cache)
1933
    {
1934
      CORE_ADDR func_start, stop_addr;
1935
 
1936
      *this_prologue_cache
1937
        = FRAME_OBSTACK_ZALLOC (struct mep_prologue);
1938
 
1939
      func_start = frame_func_unwind (next_frame, NORMAL_FRAME);
1940
      stop_addr = frame_pc_unwind (next_frame);
1941
 
1942
      /* If we couldn't find any function containing the PC, then
1943
         just initialize the prologue cache, but don't do anything.  */
1944
      if (! func_start)
1945
        stop_addr = func_start;
1946
 
1947
      mep_analyze_prologue (func_start, stop_addr, *this_prologue_cache);
1948
    }
1949
 
1950
  return *this_prologue_cache;
1951
}
1952
 
1953
 
1954
/* Given the next frame and a prologue cache, return this frame's
1955
   base.  */
1956
static CORE_ADDR
1957
mep_frame_base (struct frame_info *next_frame,
1958
                void **this_prologue_cache)
1959
{
1960
  struct mep_prologue *p
1961
    = mep_analyze_frame_prologue (next_frame, this_prologue_cache);
1962
 
1963
  /* In functions that use alloca, the distance between the stack
1964
     pointer and the frame base varies dynamically, so we can't use
1965
     the SP plus static information like prologue analysis to find the
1966
     frame base.  However, such functions must have a frame pointer,
1967
     to be able to restore the SP on exit.  So whenever we do have a
1968
     frame pointer, use that to find the base.  */
1969
  if (p->has_frame_ptr)
1970
    {
1971
      CORE_ADDR fp
1972
        = frame_unwind_register_unsigned (next_frame, MEP_FP_REGNUM);
1973
      return fp - p->frame_ptr_offset;
1974
    }
1975
  else
1976
    {
1977
      CORE_ADDR sp
1978
        = frame_unwind_register_unsigned (next_frame, MEP_SP_REGNUM);
1979
      return sp - p->frame_size;
1980
    }
1981
}
1982
 
1983
 
1984
static void
1985
mep_frame_this_id (struct frame_info *next_frame,
1986
                   void **this_prologue_cache,
1987
                   struct frame_id *this_id)
1988
{
1989
  *this_id = frame_id_build (mep_frame_base (next_frame, this_prologue_cache),
1990
                             frame_func_unwind (next_frame, NORMAL_FRAME));
1991
}
1992
 
1993
 
1994
static void
1995
mep_frame_prev_register (struct frame_info *next_frame,
1996
                         void **this_prologue_cache,
1997
                         int regnum, int *optimizedp,
1998
                         enum lval_type *lvalp, CORE_ADDR *addrp,
1999
                         int *realnump, gdb_byte *bufferp)
2000
{
2001
  struct mep_prologue *p
2002
    = mep_analyze_frame_prologue (next_frame, this_prologue_cache);
2003
 
2004
  /* There are a number of complications in unwinding registers on the
2005
     MeP, having to do with core functions calling VLIW functions and
2006
     vice versa.
2007
 
2008
     The least significant bit of the link register, LP.LTOM, is the
2009
     VLIW mode toggle bit: it's set if a core function called a VLIW
2010
     function, or vice versa, and clear when the caller and callee
2011
     were both in the same mode.
2012
 
2013
     So, if we're asked to unwind the PC, then we really want to
2014
     unwind the LP and clear the least significant bit.  (Real return
2015
     addresses are always even.)  And if we want to unwind the program
2016
     status word (PSW), we need to toggle PSW.OM if LP.LTOM is set.
2017
 
2018
     Tweaking the register values we return in this way means that the
2019
     bits in BUFFERP[] are not the same as the bits you'd find at
2020
     ADDRP in the inferior, so we make sure lvalp is not_lval when we
2021
     do this.  */
2022
  if (regnum == MEP_PC_REGNUM)
2023
    {
2024
      mep_frame_prev_register (next_frame, this_prologue_cache, MEP_LP_REGNUM,
2025
                               optimizedp, lvalp, addrp, realnump, bufferp);
2026
      store_unsigned_integer (bufferp, MEP_LP_SIZE,
2027
                              (extract_unsigned_integer (bufferp, MEP_LP_SIZE)
2028
                               & ~1));
2029
      *lvalp = not_lval;
2030
    }
2031
  else
2032
    {
2033
      CORE_ADDR frame_base = mep_frame_base (next_frame, this_prologue_cache);
2034
      int reg_size = register_size (get_frame_arch (next_frame), regnum);
2035
 
2036
      /* Our caller's SP is our frame base.  */
2037
      if (regnum == MEP_SP_REGNUM)
2038
        {
2039
          *optimizedp = 0;
2040
          *lvalp = not_lval;
2041
          *addrp = 0;
2042
          *realnump = -1;
2043
          if (bufferp)
2044
            store_unsigned_integer (bufferp, reg_size, frame_base);
2045
        }
2046
 
2047
      /* If prologue analysis says we saved this register somewhere,
2048
         return a description of the stack slot holding it.  */
2049
      else if (p->reg_offset[regnum] != 1)
2050
        {
2051
          *optimizedp = 0;
2052
          *lvalp = lval_memory;
2053
          *addrp = frame_base + p->reg_offset[regnum];
2054
          *realnump = -1;
2055
          if (bufferp)
2056
            get_frame_memory (next_frame, *addrp, bufferp, reg_size);
2057
        }
2058
 
2059
      /* Otherwise, presume we haven't changed the value of this
2060
         register, and get it from the next frame.  */
2061
      else
2062
        frame_register_unwind (next_frame, regnum,
2063
                               optimizedp, lvalp, addrp, realnump, bufferp);
2064
 
2065
      /* If we need to toggle the operating mode, do so.  */
2066
      if (regnum == MEP_PSW_REGNUM)
2067
        {
2068
          int lp_optimized;
2069
          enum lval_type lp_lval;
2070
          CORE_ADDR lp_addr;
2071
          int lp_realnum;
2072
          char lp_buffer[MEP_LP_SIZE];
2073
 
2074
          /* Get the LP's value, too.  */
2075
          frame_register_unwind (next_frame, MEP_LP_REGNUM,
2076
                                 &lp_optimized, &lp_lval, &lp_addr,
2077
                                 &lp_realnum, lp_buffer);
2078
 
2079
          /* If LP.LTOM is set, then toggle PSW.OM.  */
2080
          if (extract_unsigned_integer (lp_buffer, MEP_LP_SIZE) & 0x1)
2081
            store_unsigned_integer
2082
              (bufferp, MEP_PSW_SIZE,
2083
               (extract_unsigned_integer (bufferp, MEP_PSW_SIZE) ^ 0x1000));
2084
          *lvalp = not_lval;
2085
        }
2086
    }
2087
}
2088
 
2089
 
2090
static const struct frame_unwind mep_frame_unwind = {
2091
  NORMAL_FRAME,
2092
  mep_frame_this_id,
2093
  mep_frame_prev_register
2094
};
2095
 
2096
 
2097
static const struct frame_unwind *
2098
mep_frame_sniffer (struct frame_info *next_frame)
2099
{
2100
  return &mep_frame_unwind;
2101
}
2102
 
2103
 
2104
/* Our general unwinding function can handle unwinding the PC.  */
2105
static CORE_ADDR
2106
mep_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
2107
{
2108
  return frame_unwind_register_unsigned (next_frame, MEP_PC_REGNUM);
2109
}
2110
 
2111
 
2112
/* Our general unwinding function can handle unwinding the SP.  */
2113
static CORE_ADDR
2114
mep_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame)
2115
{
2116
  return frame_unwind_register_unsigned (next_frame, MEP_SP_REGNUM);
2117
}
2118
 
2119
 
2120
 
2121
/* Return values.  */
2122
 
2123
 
2124
static int
2125
mep_use_struct_convention (struct type *type)
2126
{
2127
  return (TYPE_LENGTH (type) > MEP_GPR_SIZE);
2128
}
2129
 
2130
 
2131
static void
2132
mep_extract_return_value (struct gdbarch *arch,
2133
                          struct type *type,
2134
                          struct regcache *regcache,
2135
                          gdb_byte *valbuf)
2136
{
2137
  int byte_order = gdbarch_byte_order (arch);
2138
 
2139
  /* Values that don't occupy a full register appear at the less
2140
     significant end of the value.  This is the offset to where the
2141
     value starts.  */
2142
  int offset;
2143
 
2144
  /* Return values > MEP_GPR_SIZE bytes are returned in memory,
2145
     pointed to by R0.  */
2146
  gdb_assert (TYPE_LENGTH (type) <= MEP_GPR_SIZE);
2147
 
2148
  if (byte_order == BFD_ENDIAN_BIG)
2149
    offset = MEP_GPR_SIZE - TYPE_LENGTH (type);
2150
  else
2151
    offset = 0;
2152
 
2153
  /* Return values that do fit in a single register are returned in R0. */
2154
  regcache_cooked_read_part (regcache, MEP_R0_REGNUM,
2155
                             offset, TYPE_LENGTH (type),
2156
                             valbuf);
2157
}
2158
 
2159
 
2160
static void
2161
mep_store_return_value (struct gdbarch *arch,
2162
                        struct type *type,
2163
                        struct regcache *regcache,
2164
                        const gdb_byte *valbuf)
2165
{
2166
  int byte_order = gdbarch_byte_order (arch);
2167
 
2168
  /* Values that fit in a single register go in R0.  */
2169
  if (TYPE_LENGTH (type) <= MEP_GPR_SIZE)
2170
    {
2171
      /* Values that don't occupy a full register appear at the least
2172
         significant end of the value.  This is the offset to where the
2173
         value starts.  */
2174
      int offset;
2175
 
2176
      if (byte_order == BFD_ENDIAN_BIG)
2177
        offset = MEP_GPR_SIZE - TYPE_LENGTH (type);
2178
      else
2179
        offset = 0;
2180
 
2181
      regcache_cooked_write_part (regcache, MEP_R0_REGNUM,
2182
                                  offset, TYPE_LENGTH (type),
2183
                                  valbuf);
2184
    }
2185
 
2186
  /* Return values larger than a single register are returned in
2187
     memory, pointed to by R0.  Unfortunately, we can't count on R0
2188
     pointing to the return buffer, so we raise an error here. */
2189
  else
2190
    error ("GDB cannot set return values larger than four bytes; "
2191
           "the Media Processor's\n"
2192
           "calling conventions do not provide enough information "
2193
           "to do this.\n"
2194
           "Try using the 'return' command with no argument.");
2195
}
2196
 
2197
enum return_value_convention
2198
mep_return_value (struct gdbarch *gdbarch, struct type *type,
2199
                  struct regcache *regcache, gdb_byte *readbuf,
2200
                  const gdb_byte *writebuf)
2201
{
2202
  if (mep_use_struct_convention (type))
2203
    {
2204
      if (readbuf)
2205
        {
2206
          ULONGEST addr;
2207
          /* Although the address of the struct buffer gets passed in R1, it's
2208
             returned in R0.  Fetch R0's value and then read the memory
2209
             at that address.  */
2210
          regcache_raw_read_unsigned (regcache, MEP_R0_REGNUM, &addr);
2211
          read_memory (addr, readbuf, TYPE_LENGTH (type));
2212
        }
2213
      if (writebuf)
2214
        {
2215
          /* Return values larger than a single register are returned in
2216
             memory, pointed to by R0.  Unfortunately, we can't count on R0
2217
             pointing to the return buffer, so we raise an error here. */
2218
          error ("GDB cannot set return values larger than four bytes; "
2219
                 "the Media Processor's\n"
2220
                 "calling conventions do not provide enough information "
2221
                 "to do this.\n"
2222
                 "Try using the 'return' command with no argument.");
2223
        }
2224
      return RETURN_VALUE_ABI_RETURNS_ADDRESS;
2225
    }
2226
 
2227
  if (readbuf)
2228
    mep_extract_return_value (gdbarch, type, regcache, readbuf);
2229
  if (writebuf)
2230
    mep_store_return_value (gdbarch, type, regcache, writebuf);
2231
 
2232
  return RETURN_VALUE_REGISTER_CONVENTION;
2233
}
2234
 
2235
 
2236
/* Inferior calls.  */
2237
 
2238
 
2239
static CORE_ADDR
2240
mep_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp)
2241
{
2242
  /* Require word alignment.  */
2243
  return sp & -4;
2244
}
2245
 
2246
 
2247
/* From "lang_spec2.txt":
2248
 
2249
   4.2 Calling conventions
2250
 
2251
   4.2.1 Core register conventions
2252
 
2253
   - Parameters should be evaluated from left to right, and they
2254
     should be held in $1,$2,$3,$4 in order. The fifth parameter or
2255
     after should be held in the stack. If the size is larger than 4
2256
     bytes in the first four parameters, the pointer should be held in
2257
     the registers instead. If the size is larger than 4 bytes in the
2258
     fifth parameter or after, the pointer should be held in the stack.
2259
 
2260
   - Return value of a function should be held in register $0. If the
2261
     size of return value is larger than 4 bytes, $1 should hold the
2262
     pointer pointing memory that would hold the return value. In this
2263
     case, the first parameter should be held in $2, the second one in
2264
     $3, and the third one in $4, and the forth parameter or after
2265
     should be held in the stack.
2266
 
2267
   [This doesn't say so, but arguments shorter than four bytes are
2268
   passed in the least significant end of a four-byte word when
2269
   they're passed on the stack.]  */
2270
 
2271
 
2272
/* Traverse the list of ARGC arguments ARGV; for every ARGV[i] too
2273
   large to fit in a register, save it on the stack, and place its
2274
   address in COPY[i].  SP is the initial stack pointer; return the
2275
   new stack pointer.  */
2276
static CORE_ADDR
2277
push_large_arguments (CORE_ADDR sp, int argc, struct value **argv,
2278
                      CORE_ADDR copy[])
2279
{
2280
  int i;
2281
 
2282
  for (i = 0; i < argc; i++)
2283
    {
2284
      unsigned arg_len = TYPE_LENGTH (value_type (argv[i]));
2285
 
2286
      if (arg_len > MEP_GPR_SIZE)
2287
        {
2288
          /* Reserve space for the copy, and then round the SP down, to
2289
             make sure it's all aligned properly.  */
2290
          sp = (sp - arg_len) & -4;
2291
          write_memory (sp, value_contents (argv[i]), arg_len);
2292
          copy[i] = sp;
2293
        }
2294
    }
2295
 
2296
  return sp;
2297
}
2298
 
2299
 
2300
static CORE_ADDR
2301
mep_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
2302
                     struct regcache *regcache, CORE_ADDR bp_addr,
2303
                     int argc, struct value **argv, CORE_ADDR sp,
2304
                     int struct_return,
2305
                     CORE_ADDR struct_addr)
2306
{
2307
  CORE_ADDR *copy = (CORE_ADDR *) alloca (argc * sizeof (copy[0]));
2308
  CORE_ADDR func_addr = find_function_addr (function, NULL);
2309
  int i;
2310
 
2311
  /* The number of the next register available to hold an argument.  */
2312
  int arg_reg;
2313
 
2314
  /* The address of the next stack slot available to hold an argument.  */
2315
  CORE_ADDR arg_stack;
2316
 
2317
  /* The address of the end of the stack area for arguments.  This is
2318
     just for error checking.  */
2319
  CORE_ADDR arg_stack_end;
2320
 
2321
  sp = push_large_arguments (sp, argc, argv, copy);
2322
 
2323
  /* Reserve space for the stack arguments, if any.  */
2324
  arg_stack_end = sp;
2325
  if (argc + (struct_addr ? 1 : 0) > 4)
2326
    sp -= ((argc + (struct_addr ? 1 : 0)) - 4) * MEP_GPR_SIZE;
2327
 
2328
  arg_reg = MEP_R1_REGNUM;
2329
  arg_stack = sp;
2330
 
2331
  /* If we're returning a structure by value, push the pointer to the
2332
     buffer as the first argument.  */
2333
  if (struct_return)
2334
    {
2335
      regcache_cooked_write_unsigned (regcache, arg_reg, struct_addr);
2336
      arg_reg++;
2337
    }
2338
 
2339
  for (i = 0; i < argc; i++)
2340
    {
2341
      unsigned arg_size = TYPE_LENGTH (value_type (argv[i]));
2342
      ULONGEST value;
2343
 
2344
      /* Arguments that fit in a GPR get expanded to fill the GPR.  */
2345
      if (arg_size <= MEP_GPR_SIZE)
2346
        value = extract_unsigned_integer (value_contents (argv[i]),
2347
                                          TYPE_LENGTH (value_type (argv[i])));
2348
 
2349
      /* Arguments too large to fit in a GPR get copied to the stack,
2350
         and we pass a pointer to the copy.  */
2351
      else
2352
        value = copy[i];
2353
 
2354
      /* We use $1 -- $4 for passing arguments, then use the stack.  */
2355
      if (arg_reg <= MEP_R4_REGNUM)
2356
        {
2357
          regcache_cooked_write_unsigned (regcache, arg_reg, value);
2358
          arg_reg++;
2359
        }
2360
      else
2361
        {
2362
          char buf[MEP_GPR_SIZE];
2363
          store_unsigned_integer (buf, MEP_GPR_SIZE, value);
2364
          write_memory (arg_stack, buf, MEP_GPR_SIZE);
2365
          arg_stack += MEP_GPR_SIZE;
2366
        }
2367
    }
2368
 
2369
  gdb_assert (arg_stack <= arg_stack_end);
2370
 
2371
  /* Set the return address.  */
2372
  regcache_cooked_write_unsigned (regcache, MEP_LP_REGNUM, bp_addr);
2373
 
2374
  /* Update the stack pointer.  */
2375
  regcache_cooked_write_unsigned (regcache, MEP_SP_REGNUM, sp);
2376
 
2377
  return sp;
2378
}
2379
 
2380
 
2381
static struct frame_id
2382
mep_unwind_dummy_id (struct gdbarch *gdbarch, struct frame_info *next_frame)
2383
{
2384
  return frame_id_build (mep_unwind_sp (gdbarch, next_frame),
2385
                         frame_pc_unwind (next_frame));
2386
}
2387
 
2388
 
2389
 
2390
/* Initialization.  */
2391
 
2392
 
2393
static struct gdbarch *
2394
mep_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
2395
{
2396
  struct gdbarch *gdbarch;
2397
  struct gdbarch_tdep *tdep;
2398
 
2399
  /* Which me_module are we building a gdbarch object for?  */
2400
  CONFIG_ATTR me_module;
2401
 
2402
  /* If we have a BFD in hand, figure out which me_module it was built
2403
     for.  Otherwise, use the no-particular-me_module code.  */
2404
  if (info.abfd)
2405
    {
2406
      /* The way to get the me_module code depends on the object file
2407
         format.  At the moment, we only know how to handle ELF.  */
2408
      if (bfd_get_flavour (info.abfd) == bfd_target_elf_flavour)
2409
        me_module = elf_elfheader (info.abfd)->e_flags & EF_MEP_INDEX_MASK;
2410
      else
2411
        me_module = CONFIG_NONE;
2412
    }
2413
  else
2414
    me_module = CONFIG_NONE;
2415
 
2416
  /* If we're setting the architecture from a file, check the
2417
     endianness of the file against that of the me_module.  */
2418
  if (info.abfd)
2419
    {
2420
      /* The negations on either side make the comparison treat all
2421
         non-zero (true) values as equal.  */
2422
      if (! bfd_big_endian (info.abfd) != ! me_module_big_endian (me_module))
2423
        {
2424
          const char *module_name = me_module_name (me_module);
2425
          const char *module_endianness
2426
            = me_module_big_endian (me_module) ? "big" : "little";
2427
          const char *file_name = bfd_get_filename (info.abfd);
2428
          const char *file_endianness
2429
            = bfd_big_endian (info.abfd) ? "big" : "little";
2430
 
2431
          fputc_unfiltered ('\n', gdb_stderr);
2432
          if (module_name)
2433
            warning ("the MeP module '%s' is %s-endian, but the executable\n"
2434
                     "%s is %s-endian.",
2435
                     module_name, module_endianness,
2436
                     file_name, file_endianness);
2437
          else
2438
            warning ("the selected MeP module is %s-endian, but the "
2439
                     "executable\n"
2440
                     "%s is %s-endian.",
2441
                     module_endianness, file_name, file_endianness);
2442
        }
2443
    }
2444
 
2445
  /* Find a candidate among the list of architectures we've created
2446
     already.  info->bfd_arch_info needs to match, but we also want
2447
     the right me_module: the ELF header's e_flags field needs to
2448
     match as well.  */
2449
  for (arches = gdbarch_list_lookup_by_info (arches, &info);
2450
       arches != NULL;
2451
       arches = gdbarch_list_lookup_by_info (arches->next, &info))
2452
    if (gdbarch_tdep (arches->gdbarch)->me_module == me_module)
2453
      return arches->gdbarch;
2454
 
2455
  tdep = (struct gdbarch_tdep *) xmalloc (sizeof (struct gdbarch_tdep));
2456
  gdbarch = gdbarch_alloc (&info, tdep);
2457
 
2458
  /* Get a CGEN CPU descriptor for this architecture.  */
2459
  {
2460
    const char *mach_name = info.bfd_arch_info->printable_name;
2461
    enum cgen_endian endian = (info.byte_order == BFD_ENDIAN_BIG
2462
                               ? CGEN_ENDIAN_BIG
2463
                               : CGEN_ENDIAN_LITTLE);
2464
 
2465
    tdep->cpu_desc = mep_cgen_cpu_open (CGEN_CPU_OPEN_BFDMACH, mach_name,
2466
                                        CGEN_CPU_OPEN_ENDIAN, endian,
2467
                                        CGEN_CPU_OPEN_END);
2468
  }
2469
 
2470
  tdep->me_module = me_module;
2471
 
2472
  /* Register set.  */
2473
  set_gdbarch_read_pc (gdbarch, mep_read_pc);
2474
  set_gdbarch_write_pc (gdbarch, mep_write_pc);
2475
  set_gdbarch_num_regs (gdbarch, MEP_NUM_RAW_REGS);
2476
  set_gdbarch_sp_regnum (gdbarch, MEP_SP_REGNUM);
2477
  set_gdbarch_register_name (gdbarch, mep_register_name);
2478
  set_gdbarch_register_type (gdbarch, mep_register_type);
2479
  set_gdbarch_num_pseudo_regs (gdbarch, MEP_NUM_PSEUDO_REGS);
2480
  set_gdbarch_pseudo_register_read (gdbarch, mep_pseudo_register_read);
2481
  set_gdbarch_pseudo_register_write (gdbarch, mep_pseudo_register_write);
2482
  set_gdbarch_dwarf2_reg_to_regnum (gdbarch, mep_debug_reg_to_regnum);
2483
  set_gdbarch_stab_reg_to_regnum (gdbarch, mep_debug_reg_to_regnum);
2484
 
2485
  set_gdbarch_register_reggroup_p (gdbarch, mep_register_reggroup_p);
2486
  reggroup_add (gdbarch, all_reggroup);
2487
  reggroup_add (gdbarch, general_reggroup);
2488
  reggroup_add (gdbarch, save_reggroup);
2489
  reggroup_add (gdbarch, restore_reggroup);
2490
  reggroup_add (gdbarch, mep_csr_reggroup);
2491
  reggroup_add (gdbarch, mep_cr_reggroup);
2492
  reggroup_add (gdbarch, mep_ccr_reggroup);
2493
 
2494
  /* Disassembly.  */
2495
  set_gdbarch_print_insn (gdbarch, mep_gdb_print_insn);
2496
 
2497
  /* Breakpoints.  */
2498
  set_gdbarch_breakpoint_from_pc (gdbarch, mep_breakpoint_from_pc);
2499
  set_gdbarch_decr_pc_after_break (gdbarch, 0);
2500
  set_gdbarch_skip_prologue (gdbarch, mep_skip_prologue);
2501
 
2502
  /* Frames and frame unwinding.  */
2503
  frame_unwind_append_sniffer (gdbarch, mep_frame_sniffer);
2504
  set_gdbarch_unwind_pc (gdbarch, mep_unwind_pc);
2505
  set_gdbarch_unwind_sp (gdbarch, mep_unwind_sp);
2506
  set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
2507
  set_gdbarch_frame_args_skip (gdbarch, 0);
2508
 
2509
  /* Return values.  */
2510
  set_gdbarch_return_value (gdbarch, mep_return_value);
2511
 
2512
  /* Inferior function calls.  */
2513
  set_gdbarch_frame_align (gdbarch, mep_frame_align);
2514
  set_gdbarch_push_dummy_call (gdbarch, mep_push_dummy_call);
2515
  set_gdbarch_unwind_dummy_id (gdbarch, mep_unwind_dummy_id);
2516
 
2517
  return gdbarch;
2518
}
2519
 
2520
 
2521
void
2522
_initialize_mep_tdep (void)
2523
{
2524
  mep_csr_reggroup = reggroup_new ("csr", USER_REGGROUP);
2525
  mep_cr_reggroup  = reggroup_new ("cr", USER_REGGROUP);
2526
  mep_ccr_reggroup = reggroup_new ("ccr", USER_REGGROUP);
2527
 
2528
  register_gdbarch_init (bfd_arch_mep, mep_gdbarch_init);
2529
 
2530
  mep_init_pseudoregister_maps ();
2531
}

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