gdb/bfin-tdep.c

   1 /* Target-dependent code for Analog Devices Blackfin processor, for GDB.
   2
   3    Copyright (C) 2005-2020 Free Software Foundation, Inc.
   4
   5    Contributed by Analog Devices, Inc.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22 #include "defs.h"
  23 #include "inferior.h"
  24 #include "gdbcore.h"
  25 #include "arch-utils.h"
  26 #include "regcache.h"
  27 #include "frame.h"
  28 #include "frame-unwind.h"
  29 #include "frame-base.h"
  30 #include "trad-frame.h"
  31 #include "dis-asm.h"
  32 #include "sim-regno.h"
  33 #include "gdb/sim-bfin.h"
  34 #include "dwarf2-frame.h"
  35 #include "symtab.h"
  36 #include "elf-bfd.h"
  37 #include "elf/bfin.h"
  38 #include "osabi.h"
  39 #include "infcall.h"
  40 #include "xml-syscall.h"
  41 #include "bfin-tdep.h"
  42
  43 /* Macros used by prologue functions.  */
  44 #define P_LINKAGE                       0xE800
  45 #define P_MINUS_SP1                     0x0140
  46 #define P_MINUS_SP2                     0x05C0
  47 #define P_MINUS_SP3                     0x0540
  48 #define P_MINUS_SP4                     0x04C0
  49 #define P_SP_PLUS                       0x6C06
  50 #define P_P2_LOW                        0xE10A
  51 #define P_P2_HIGH                       0XE14A
  52 #define P_SP_EQ_SP_PLUS_P2              0X5BB2
  53 #define P_SP_EQ_P2_PLUS_SP              0x5B96
  54 #define P_MINUS_MINUS_SP_EQ_RETS        0x0167
  55
  56 /* Macros used for program flow control.  */
  57 /* 16 bit instruction, max  */
  58 #define P_16_BIT_INSR_MAX               0xBFFF
  59 /* 32 bit instruction, min  */
  60 #define P_32_BIT_INSR_MIN               0xC000
  61 /* 32 bit instruction, max  */
  62 #define P_32_BIT_INSR_MAX               0xE801
  63 /* jump (preg), 16-bit, min  */
  64 #define P_JUMP_PREG_MIN                 0x0050
  65 /* jump (preg), 16-bit, max  */
  66 #define P_JUMP_PREG_MAX                 0x0057
  67 /* jump (pc+preg), 16-bit, min  */
  68 #define P_JUMP_PC_PLUS_PREG_MIN         0x0080
  69 /* jump (pc+preg), 16-bit, max  */
  70 #define P_JUMP_PC_PLUS_PREG_MAX         0x0087
  71 /* jump.s pcrel13m2, 16-bit, min  */
  72 #define P_JUMP_S_MIN                    0x2000
  73 /* jump.s pcrel13m2, 16-bit, max  */
  74 #define P_JUMP_S_MAX                    0x2FFF
  75 /* jump.l pcrel25m2, 32-bit, min  */
  76 #define P_JUMP_L_MIN                    0xE200
  77 /* jump.l pcrel25m2, 32-bit, max  */
  78 #define P_JUMP_L_MAX                    0xE2FF
  79 /* conditional jump pcrel11m2, 16-bit, min  */
  80 #define P_IF_CC_JUMP_MIN                0x1800
  81 /* conditional jump pcrel11m2, 16-bit, max  */
  82 #define P_IF_CC_JUMP_MAX                0x1BFF
  83 /* conditional jump(bp) pcrel11m2, 16-bit, min  */
  84 #define P_IF_CC_JUMP_BP_MIN             0x1C00
  85 /* conditional jump(bp) pcrel11m2, 16-bit, max  */
  86 #define P_IF_CC_JUMP_BP_MAX             0x1FFF
  87 /* conditional !jump pcrel11m2, 16-bit, min  */
  88 #define P_IF_NOT_CC_JUMP_MIN            0x1000
  89 /* conditional !jump pcrel11m2, 16-bit, max  */
  90 #define P_IF_NOT_CC_JUMP_MAX            0x13FF
  91 /* conditional jump(bp) pcrel11m2, 16-bit, min  */
  92 #define P_IF_NOT_CC_JUMP_BP_MIN         0x1400
  93 /* conditional jump(bp) pcrel11m2, 16-bit, max  */
  94 #define P_IF_NOT_CC_JUMP_BP_MAX         0x17FF
  95 /* call (preg), 16-bit, min  */
  96 #define P_CALL_PREG_MIN                 0x0060
  97 /* call (preg), 16-bit, max  */
  98 #define P_CALL_PREG_MAX                 0x0067
  99 /* call (pc+preg), 16-bit, min  */
 100 #define P_CALL_PC_PLUS_PREG_MIN         0x0070
 101 /* call (pc+preg), 16-bit, max  */
 102 #define P_CALL_PC_PLUS_PREG_MAX         0x0077
 103 /* call pcrel25m2, 32-bit, min  */
 104 #define P_CALL_MIN                      0xE300
 105 /* call pcrel25m2, 32-bit, max  */
 106 #define P_CALL_MAX                      0xE3FF
 107 /* RTS  */
 108 #define P_RTS                           0x0010
 109 /* MNOP  */
 110 #define P_MNOP                          0xC803
 111 /* EXCPT, 16-bit, min  */
 112 #define P_EXCPT_MIN                     0x00A0
 113 /* EXCPT, 16-bit, max  */
 114 #define P_EXCPT_MAX                     0x00AF
 115 /* multi instruction mask 1, 16-bit  */
 116 #define P_BIT_MULTI_INS_1               0xC000
 117 /* multi instruction mask 2, 16-bit  */
 118 #define P_BIT_MULTI_INS_2               0x0800
 119
 120 /* The maximum bytes we search to skip the prologue.  */
 121 #define UPPER_LIMIT                     40
 122
 123 /* ASTAT bits  */
 124 #define ASTAT_CC_POS                    5
 125 #define ASTAT_CC                        (1 << ASTAT_CC_POS)
 126
 127 /* Initial value: Register names used in BFIN's ISA documentation.  */
 128
 129 static const char * const bfin_register_name_strings[] =
 130 {
 131   "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
 132   "p0", "p1", "p2", "p3", "p4", "p5", "sp", "fp",
 133   "i0", "i1", "i2", "i3", "m0", "m1", "m2", "m3",
 134   "b0", "b1", "b2", "b3", "l0", "l1", "l2", "l3",
 135   "a0x", "a0w", "a1x", "a1w", "astat", "rets",
 136   "lc0", "lt0", "lb0", "lc1", "lt1", "lb1", "cycles", "cycles2",
 137   "usp", "seqstat", "syscfg", "reti", "retx", "retn", "rete",
 138   "pc", "cc",
 139 };
 140
 141 #define NUM_BFIN_REGNAMES ARRAY_SIZE (bfin_register_name_strings)
 142
 143
 144 /* In this diagram successive memory locations increase downwards or the
 145    stack grows upwards with negative indices.  (PUSH analogy for stack.)
 146
 147    The top frame is the "frame" of the current function being executed.
 148
 149      +--------------+ SP    -
 150      |  local vars  |       ^
 151      +--------------+       |
 152      |  save regs   |       |
 153      +--------------+ FP    |
 154      |   old FP    -|--    top
 155      +--------------+  |  frame
 156      |    RETS      |  |    |
 157      +--------------+  |    |
 158      |   param 1    |  |    |
 159      |   param 2    |  |    |
 160      |    ...       |  |    V
 161      +--------------+  |    -
 162      |  local vars  |  |    ^
 163      +--------------+  |    |
 164      |  save regs   |  |    |
 165      +--------------+<-     |
 166      |   old FP    -|--   next
 167      +--------------+  |  frame
 168      |    RETS      |  |    |
 169      +--------------+  |    |
 170      |   param 1    |  |    |
 171      |   param 2    |  |    |
 172      |    ...       |  |    V
 173      +--------------+  |    -
 174      |  local vars  |  |    ^
 175      +--------------+  |    |
 176      |  save regs   |  |    |
 177      +--------------+<-  next frame
 178      |   old FP     |       |
 179      +--------------+       |
 180      |    RETS      |       V
 181      +--------------+       -
 182
 183    The frame chain is formed as following:
 184
 185      FP has the topmost frame.
 186      FP + 4 has the previous FP and so on.  */
 187
 188
 189 /* Map from DWARF2 register number to GDB register number.  */
 190
 191 static const int map_gcc_gdb[] =
 192 {
 193   BFIN_R0_REGNUM,
 194   BFIN_R1_REGNUM,
 195   BFIN_R2_REGNUM,
 196   BFIN_R3_REGNUM,
 197   BFIN_R4_REGNUM,
 198   BFIN_R5_REGNUM,
 199   BFIN_R6_REGNUM,
 200   BFIN_R7_REGNUM,
 201   BFIN_P0_REGNUM,
 202   BFIN_P1_REGNUM,
 203   BFIN_P2_REGNUM,
 204   BFIN_P3_REGNUM,
 205   BFIN_P4_REGNUM,
 206   BFIN_P5_REGNUM,
 207   BFIN_SP_REGNUM,
 208   BFIN_FP_REGNUM,
 209   BFIN_I0_REGNUM,
 210   BFIN_I1_REGNUM,
 211   BFIN_I2_REGNUM,
 212   BFIN_I3_REGNUM,
 213   BFIN_B0_REGNUM,
 214   BFIN_B1_REGNUM,
 215   BFIN_B2_REGNUM,
 216   BFIN_B3_REGNUM,
 217   BFIN_L0_REGNUM,
 218   BFIN_L1_REGNUM,
 219   BFIN_L2_REGNUM,
 220   BFIN_L3_REGNUM,
 221   BFIN_M0_REGNUM,
 222   BFIN_M1_REGNUM,
 223   BFIN_M2_REGNUM,
 224   BFIN_M3_REGNUM,
 225   BFIN_A0_DOT_X_REGNUM,
 226   BFIN_A1_DOT_X_REGNUM,
 227   BFIN_CC_REGNUM,
 228   BFIN_RETS_REGNUM,
 229   BFIN_RETI_REGNUM,
 230   BFIN_RETX_REGNUM,
 231   BFIN_RETN_REGNUM,
 232   BFIN_RETE_REGNUM,
 233   BFIN_ASTAT_REGNUM,
 234   BFIN_SEQSTAT_REGNUM,
 235   BFIN_USP_REGNUM,
 236   BFIN_LT0_REGNUM,
 237   BFIN_LT1_REGNUM,
 238   BFIN_LC0_REGNUM,
 239   BFIN_LC1_REGNUM,
 240   BFIN_LB0_REGNUM,
 241   BFIN_LB1_REGNUM
 242 };
 243
 244 /* Big enough to hold the size of the largest register in bytes.  */
 245 #define BFIN_MAX_REGISTER_SIZE  4
 246
 247 struct bfin_frame_cache
 248 {
 249   /* Base address.  */
 250   CORE_ADDR base;
 251   CORE_ADDR sp_offset;
 252   CORE_ADDR pc;
 253   int frameless_pc_value;
 254
 255   /* Saved registers.  */
 256   CORE_ADDR saved_regs[BFIN_NUM_REGS];
 257   CORE_ADDR saved_sp;
 258
 259   /* Stack space reserved for local variables.  */
 260   long locals;
 261 };
 262
 263 /* Allocate and initialize a frame cache.  */
 264
 265 static struct bfin_frame_cache *
 266 bfin_alloc_frame_cache (void)
 267 {
 268   struct bfin_frame_cache *cache;
 269   int i;
 270
 271   cache = FRAME_OBSTACK_ZALLOC (struct bfin_frame_cache);
 272
 273   /* Base address.  */
 274   cache->base = 0;
 275   cache->sp_offset = -4;
 276   cache->pc = 0;
 277   cache->frameless_pc_value = 0;
 278
 279   /* Saved registers.  We initialize these to -1 since zero is a valid
 280      offset (that's where fp is supposed to be stored).  */
 281   for (i = 0; i < BFIN_NUM_REGS; i++)
 282     cache->saved_regs[i] = -1;
 283
 284   /* Frameless until proven otherwise.  */
 285   cache->locals = -1;
 286
 287   return cache;
 288 }
 289
 290 static struct bfin_frame_cache *
 291 bfin_frame_cache (struct frame_info *this_frame, void **this_cache)
 292 {
 293   struct bfin_frame_cache *cache;
 294   int i;
 295
 296   if (*this_cache)
 297     return (struct bfin_frame_cache *) *this_cache;
 298
 299   cache = bfin_alloc_frame_cache ();
 300   *this_cache = cache;
 301
 302   cache->base = get_frame_register_unsigned (this_frame, BFIN_FP_REGNUM);
 303   if (cache->base == 0)
 304     return cache;
 305
 306   /* For normal frames, PC is stored at [FP + 4].  */
 307   cache->saved_regs[BFIN_PC_REGNUM] = 4;
 308   cache->saved_regs[BFIN_FP_REGNUM] = 0;
 309
 310   /* Adjust all the saved registers such that they contain addresses
 311      instead of offsets.  */
 312   for (i = 0; i < BFIN_NUM_REGS; i++)
 313     if (cache->saved_regs[i] != -1)
 314       cache->saved_regs[i] += cache->base;
 315
 316   cache->pc = get_frame_func (this_frame) ;
 317   if (cache->pc == 0 || cache->pc == get_frame_pc (this_frame))
 318     {
 319       /* Either there is no prologue (frameless function) or we are at
 320          the start of a function.  In short we do not have a frame.
 321          PC is stored in rets register.  FP points to previous frame.  */
 322
 323       cache->saved_regs[BFIN_PC_REGNUM] =
 324         get_frame_register_unsigned (this_frame, BFIN_RETS_REGNUM);
 325       cache->frameless_pc_value = 1;
 326       cache->base = get_frame_register_unsigned (this_frame, BFIN_FP_REGNUM);
 327       cache->saved_regs[BFIN_FP_REGNUM] = cache->base;
 328       cache->saved_sp = cache->base;
 329     }
 330   else
 331     {
 332       cache->frameless_pc_value = 0;
 333
 334       /* Now that we have the base address for the stack frame we can
 335          calculate the value of SP in the calling frame.  */
 336       cache->saved_sp = cache->base + 8;
 337     }
 338
 339   return cache;
 340 }
 341
 342 static void
 343 bfin_frame_this_id (struct frame_info *this_frame,
 344                     void **this_cache,
 345                     struct frame_id *this_id)
 346 {
 347   struct bfin_frame_cache *cache = bfin_frame_cache (this_frame, this_cache);
 348
 349   /* This marks the outermost frame.  */
 350   if (cache->base == 0)
 351     return;
 352
 353   /* See the end of bfin_push_dummy_call.  */
 354   *this_id = frame_id_build (cache->base + 8, cache->pc);
 355 }
 356
 357 static struct value *
 358 bfin_frame_prev_register (struct frame_info *this_frame,
 359                           void **this_cache,
 360                           int regnum)
 361 {
 362   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 363   struct bfin_frame_cache *cache = bfin_frame_cache (this_frame, this_cache);
 364
 365   if (regnum == gdbarch_sp_regnum (gdbarch) && cache->saved_sp)
 366     return frame_unwind_got_constant (this_frame, regnum, cache->saved_sp);
 367
 368   if (regnum < BFIN_NUM_REGS && cache->saved_regs[regnum] != -1)
 369     return frame_unwind_got_memory (this_frame, regnum,
 370                                     cache->saved_regs[regnum]);
 371
 372   return frame_unwind_got_register (this_frame, regnum, regnum);
 373 }
 374
 375 static const struct frame_unwind bfin_frame_unwind =
 376 {
 377   NORMAL_FRAME,
 378   default_frame_unwind_stop_reason,
 379   bfin_frame_this_id,
 380   bfin_frame_prev_register,
 381   NULL,
 382   default_frame_sniffer
 383 };
 384
 385 /* Check for "[--SP] = <reg>;" insns.  These are appear in function
 386    prologues to save misc registers onto the stack.  */
 387
 388 static int
 389 is_minus_minus_sp (int op)
 390 {
 391   op &= 0xFFC0;
 392
 393   if ((op == P_MINUS_SP1) || (op == P_MINUS_SP2)
 394       || (op == P_MINUS_SP3) || (op == P_MINUS_SP4))
 395     return 1;
 396
 397   return 0;
 398 }
 399
 400 /* Skip all the insns that appear in generated function prologues.  */
 401
 402 static CORE_ADDR
 403 bfin_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
 404 {
 405   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 406   int op = read_memory_unsigned_integer (pc, 2, byte_order);
 407   CORE_ADDR orig_pc = pc;
 408   int done = 0;
 409
 410   /* The new gcc prologue generates the register saves BEFORE the link
 411      or RETS saving instruction.
 412      So, our job is to stop either at those instructions or some upper
 413      limit saying there is no frame!  */
 414
 415   while (!done)
 416     {
 417       if (is_minus_minus_sp (op))
 418         {
 419           while (is_minus_minus_sp (op))
 420             {
 421               pc += 2;
 422               op = read_memory_unsigned_integer (pc, 2, byte_order);
 423             }
 424
 425           if (op == P_LINKAGE)
 426             pc += 4;
 427
 428           done = 1;
 429         }
 430       else if (op == P_LINKAGE)
 431         {
 432           pc += 4;
 433           done = 1;
 434         }
 435       else if (op == P_MINUS_MINUS_SP_EQ_RETS)
 436         {
 437           pc += 2;
 438           done = 1;
 439         }
 440       else if (op == P_RTS)
 441         {
 442           done = 1;
 443         }
 444       else if ((op >= P_JUMP_PREG_MIN && op <= P_JUMP_PREG_MAX)
 445                || (op >= P_JUMP_PC_PLUS_PREG_MIN
 446                    && op <= P_JUMP_PC_PLUS_PREG_MAX)
 447                || (op == P_JUMP_S_MIN && op <= P_JUMP_S_MAX))
 448         {
 449           done = 1;
 450         }
 451       else if (pc - orig_pc >= UPPER_LIMIT)
 452         {
 453           warning (_("Function Prologue not recognised; "
 454                      "pc will point to ENTRY_POINT of the function"));
 455           pc = orig_pc + 2;
 456           done = 1;
 457         }
 458       else
 459         {
 460           pc += 2; /* Not a terminating instruction go on.  */
 461           op = read_memory_unsigned_integer (pc, 2, byte_order);
 462         }
 463     }
 464
 465    /* TODO:
 466       Dwarf2 uses entry point value AFTER some register initializations.
 467       We should perhaps skip such asssignments as well (R6 = R1, ...).  */
 468
 469   return pc;
 470 }
 471
 472 /* Return the GDB type object for the "standard" data type of data in
 473    register N.  This should be void pointer for P0-P5, SP, FP;
 474    void pointer to function for PC; int otherwise.  */
 475
 476 static struct type *
 477 bfin_register_type (struct gdbarch *gdbarch, int regnum)
 478 {
 479   if ((regnum >= BFIN_P0_REGNUM && regnum <= BFIN_FP_REGNUM)
 480       || regnum == BFIN_USP_REGNUM)
 481     return builtin_type (gdbarch)->builtin_data_ptr;
 482
 483   if (regnum == BFIN_PC_REGNUM || regnum == BFIN_RETS_REGNUM
 484       || regnum == BFIN_RETI_REGNUM || regnum == BFIN_RETX_REGNUM
 485       || regnum == BFIN_RETN_REGNUM || regnum == BFIN_RETE_REGNUM
 486       || regnum == BFIN_LT0_REGNUM || regnum == BFIN_LB0_REGNUM
 487       || regnum == BFIN_LT1_REGNUM || regnum == BFIN_LB1_REGNUM)
 488     return builtin_type (gdbarch)->builtin_func_ptr;
 489
 490   return builtin_type (gdbarch)->builtin_int32;
 491 }
 492
 493 static CORE_ADDR
 494 bfin_push_dummy_call (struct gdbarch *gdbarch,
 495                       struct value *function,
 496                       struct regcache *regcache,
 497                       CORE_ADDR bp_addr,
 498                       int nargs,
 499                       struct value **args,
 500                       CORE_ADDR sp,
 501                       function_call_return_method return_method,
 502                       CORE_ADDR struct_addr)
 503 {
 504   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 505   int i;
 506   long reg_r0, reg_r1, reg_r2;
 507   int total_len = 0;
 508
 509   for (i = nargs - 1; i >= 0; i--)
 510     {
 511       struct type *value_type = value_enclosing_type (args[i]);
 512
 513       total_len += (TYPE_LENGTH (value_type) + 3) & ~3;
 514     }
 515
 516   /* At least twelve bytes of stack space must be allocated for the function's
 517      arguments, even for functions that have less than 12 bytes of argument
 518      data.  */
 519
 520   if (total_len < 12)
 521     sp -= 12 - total_len;
 522
 523   /* Push arguments in reverse order.  */
 524
 525   for (i = nargs - 1; i >= 0; i--)
 526     {
 527       struct type *value_type = value_enclosing_type (args[i]);
 528       struct type *arg_type = check_typedef (value_type);
 529       int container_len = (TYPE_LENGTH (arg_type) + 3) & ~3;
 530
 531       sp -= container_len;
 532       write_memory (sp, value_contents (args[i]), container_len);
 533     }
 534
 535   /* Initialize R0, R1, and R2 to the first 3 words of parameters.  */
 536
 537   reg_r0 = read_memory_integer (sp, 4, byte_order);
 538   regcache_cooked_write_unsigned (regcache, BFIN_R0_REGNUM, reg_r0);
 539   reg_r1 = read_memory_integer (sp + 4, 4, byte_order);
 540   regcache_cooked_write_unsigned (regcache, BFIN_R1_REGNUM, reg_r1);
 541   reg_r2 = read_memory_integer (sp + 8, 4, byte_order);
 542   regcache_cooked_write_unsigned (regcache, BFIN_R2_REGNUM, reg_r2);
 543
 544   /* Store struct value address.  */
 545
 546   if (return_method == return_method_struct)
 547     regcache_cooked_write_unsigned (regcache, BFIN_P0_REGNUM, struct_addr);
 548
 549   /* Set the dummy return value to bp_addr.
 550      A dummy breakpoint will be setup to execute the call.  */
 551
 552   regcache_cooked_write_unsigned (regcache, BFIN_RETS_REGNUM, bp_addr);
 553
 554   /* Finally, update the stack pointer.  */
 555
 556   regcache_cooked_write_unsigned (regcache, BFIN_SP_REGNUM, sp);
 557
 558   return sp;
 559 }
 560
 561 /* Convert DWARF2 register number REG to the appropriate register number
 562    used by GDB.  */
 563
 564 static int
 565 bfin_reg_to_regnum (struct gdbarch *gdbarch, int reg)
 566 {
 567   if (reg < 0 || reg >= ARRAY_SIZE (map_gcc_gdb))
 568     return -1;
 569
 570   return map_gcc_gdb[reg];
 571 }
 572
 573 /* Implement the breakpoint_kind_from_pc gdbarch method.  */
 574
 575 static int
 576 bfin_breakpoint_kind_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr)
 577 {
 578   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 579   unsigned short iw;
 580
 581   iw = read_memory_unsigned_integer (*pcptr, 2, byte_order);
 582
 583   if ((iw & 0xf000) >= 0xc000)
 584     /* 32-bit instruction.  */
 585     return 4;
 586   else
 587     return 2;
 588 }
 589
 590 /* Implement the sw_breakpoint_from_kind gdbarch method.  */
 591
 592 static const gdb_byte *
 593 bfin_sw_breakpoint_from_kind (struct gdbarch *gdbarch, int kind, int *size)
 594 {
 595   static unsigned char bfin_breakpoint[] = {0xa1, 0x00, 0x00, 0x00};
 596   static unsigned char bfin_sim_breakpoint[] = {0x25, 0x00, 0x00, 0x00};
 597
 598   *size = kind;
 599
 600   if (strcmp (target_shortname, "sim") == 0)
 601     return bfin_sim_breakpoint;
 602   else
 603     return bfin_breakpoint;
 604 }
 605
 606 static void
 607 bfin_extract_return_value (struct type *type,
 608                            struct regcache *regs,
 609                            gdb_byte *dst)
 610 {
 611   struct gdbarch *gdbarch = regs->arch ();
 612   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 613   bfd_byte *valbuf = dst;
 614   int len = TYPE_LENGTH (type);
 615   ULONGEST tmp;
 616   int regno = BFIN_R0_REGNUM;
 617
 618   gdb_assert (len <= 8);
 619
 620   while (len > 0)
 621     {
 622       regcache_cooked_read_unsigned (regs, regno++, &tmp);
 623       store_unsigned_integer (valbuf, (len > 4 ? 4 : len), byte_order, tmp);
 624       len -= 4;
 625       valbuf += 4;
 626     }
 627 }
 628
 629 /* Write into appropriate registers a function return value of type
 630    TYPE, given in virtual format.  */
 631
 632 static void
 633 bfin_store_return_value (struct type *type,
 634                          struct regcache *regs,
 635                          const gdb_byte *src)
 636 {
 637   const bfd_byte *valbuf = src;
 638
 639   /* Integral values greater than one word are stored in consecutive
 640      registers starting with R0.  This will always be a multiple of
 641      the register size.  */
 642
 643   int len = TYPE_LENGTH (type);
 644   int regno = BFIN_R0_REGNUM;
 645
 646   gdb_assert (len <= 8);
 647
 648   while (len > 0)
 649     {
 650       regs->cooked_write (regno++, valbuf);
 651       len -= 4;
 652       valbuf += 4;
 653     }
 654 }
 655
 656 /* Determine, for architecture GDBARCH, how a return value of TYPE
 657    should be returned.  If it is supposed to be returned in registers,
 658    and READBUF is nonzero, read the appropriate value from REGCACHE,
 659    and copy it into READBUF.  If WRITEBUF is nonzero, write the value
 660    from WRITEBUF into REGCACHE.  */
 661
 662 static enum return_value_convention
 663 bfin_return_value (struct gdbarch *gdbarch,
 664                    struct value *function,
 665                    struct type *type,
 666                    struct regcache *regcache,
 667                    gdb_byte *readbuf,
 668                    const gdb_byte *writebuf)
 669 {
 670   if (TYPE_LENGTH (type) > 8)
 671     return RETURN_VALUE_STRUCT_CONVENTION;
 672
 673   if (readbuf)
 674     bfin_extract_return_value (type, regcache, readbuf);
 675
 676   if (writebuf)
 677     bfin_store_return_value (type, regcache, writebuf);
 678
 679   return RETURN_VALUE_REGISTER_CONVENTION;
 680 }
 681
 682 /* Return the BFIN register name corresponding to register I.  */
 683
 684 static const char *
 685 bfin_register_name (struct gdbarch *gdbarch, int i)
 686 {
 687   return bfin_register_name_strings[i];
 688 }
 689
 690 static enum register_status
 691 bfin_pseudo_register_read (struct gdbarch *gdbarch, readable_regcache *regcache,
 692                            int regnum, gdb_byte *buffer)
 693 {
 694   gdb_byte buf[BFIN_MAX_REGISTER_SIZE];
 695   enum register_status status;
 696
 697   if (regnum != BFIN_CC_REGNUM)
 698     internal_error (__FILE__, __LINE__,
 699                     _("invalid register number %d"), regnum);
 700
 701   /* Extract the CC bit from the ASTAT register.  */
 702   status = regcache->raw_read (BFIN_ASTAT_REGNUM, buf);
 703   if (status == REG_VALID)
 704     {
 705       buffer[1] = buffer[2] = buffer[3] = 0;
 706       buffer[0] = !!(buf[0] & ASTAT_CC);
 707     }
 708   return status;
 709 }
 710
 711 static void
 712 bfin_pseudo_register_write (struct gdbarch *gdbarch, struct regcache *regcache,
 713                             int regnum, const gdb_byte *buffer)
 714 {
 715   gdb_byte buf[BFIN_MAX_REGISTER_SIZE];
 716
 717   if (regnum != BFIN_CC_REGNUM)
 718     internal_error (__FILE__, __LINE__,
 719                     _("invalid register number %d"), regnum);
 720
 721   /* Overlay the CC bit in the ASTAT register.  */
 722   regcache->raw_read (BFIN_ASTAT_REGNUM, buf);
 723   buf[0] = (buf[0] & ~ASTAT_CC) | ((buffer[0] & 1) << ASTAT_CC_POS);
 724   regcache->raw_write (BFIN_ASTAT_REGNUM, buf);
 725 }
 726
 727 static CORE_ADDR
 728 bfin_frame_base_address (struct frame_info *this_frame, void **this_cache)
 729 {
 730   struct bfin_frame_cache *cache = bfin_frame_cache (this_frame, this_cache);
 731
 732   return cache->base;
 733 }
 734
 735 static CORE_ADDR
 736 bfin_frame_local_address (struct frame_info *this_frame, void **this_cache)
 737 {
 738   struct bfin_frame_cache *cache = bfin_frame_cache (this_frame, this_cache);
 739
 740   return cache->base - 4;
 741 }
 742
 743 static CORE_ADDR
 744 bfin_frame_args_address (struct frame_info *this_frame, void **this_cache)
 745 {
 746   struct bfin_frame_cache *cache = bfin_frame_cache (this_frame, this_cache);
 747
 748   return cache->base + 8;
 749 }
 750
 751 static const struct frame_base bfin_frame_base =
 752 {
 753   &bfin_frame_unwind,
 754   bfin_frame_base_address,
 755   bfin_frame_local_address,
 756   bfin_frame_args_address
 757 };
 758
 759 static CORE_ADDR
 760 bfin_frame_align (struct gdbarch *gdbarch, CORE_ADDR address)
 761 {
 762   return (address & ~0x3);
 763 }
 764
 765 enum bfin_abi
 766 bfin_abi (struct gdbarch *gdbarch)
 767 {
 768   return gdbarch_tdep (gdbarch)->bfin_abi;
 769 }
 770
 771 /* Initialize the current architecture based on INFO.  If possible,
 772    re-use an architecture from ARCHES, which is a list of
 773    architectures already created during this debugging session.
 774
 775    Called e.g. at program startup, when reading a core file, and when
 776    reading a binary file.  */
 777
 778 static struct gdbarch *
 779 bfin_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 780 {
 781   struct gdbarch_tdep *tdep;
 782   struct gdbarch *gdbarch;
 783   enum bfin_abi abi;
 784
 785   abi = BFIN_ABI_FLAT;
 786
 787   /* If there is already a candidate, use it.  */
 788
 789   for (arches = gdbarch_list_lookup_by_info (arches, &info);
 790        arches != NULL;
 791        arches = gdbarch_list_lookup_by_info (arches->next, &info))
 792     {
 793       if (gdbarch_tdep (arches->gdbarch)->bfin_abi != abi)
 794         continue;
 795       return arches->gdbarch;
 796     }
 797
 798   tdep = XCNEW (struct gdbarch_tdep);
 799   gdbarch = gdbarch_alloc (&info, tdep);
 800
 801   tdep->bfin_abi = abi;
 802
 803   set_gdbarch_num_regs (gdbarch, BFIN_NUM_REGS);
 804   set_gdbarch_pseudo_register_read (gdbarch, bfin_pseudo_register_read);
 805   set_gdbarch_pseudo_register_write (gdbarch, bfin_pseudo_register_write);
 806   set_gdbarch_num_pseudo_regs (gdbarch, BFIN_NUM_PSEUDO_REGS);
 807   set_gdbarch_sp_regnum (gdbarch, BFIN_SP_REGNUM);
 808   set_gdbarch_pc_regnum (gdbarch, BFIN_PC_REGNUM);
 809   set_gdbarch_ps_regnum (gdbarch, BFIN_ASTAT_REGNUM);
 810   set_gdbarch_dwarf2_reg_to_regnum (gdbarch, bfin_reg_to_regnum);
 811   set_gdbarch_register_name (gdbarch, bfin_register_name);
 812   set_gdbarch_register_type (gdbarch, bfin_register_type);
 813   set_gdbarch_push_dummy_call (gdbarch, bfin_push_dummy_call);
 814   set_gdbarch_believe_pcc_promotion (gdbarch, 1);
 815   set_gdbarch_return_value (gdbarch, bfin_return_value);
 816   set_gdbarch_skip_prologue (gdbarch, bfin_skip_prologue);
 817   set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
 818   set_gdbarch_breakpoint_kind_from_pc (gdbarch, bfin_breakpoint_kind_from_pc);
 819   set_gdbarch_sw_breakpoint_from_kind (gdbarch, bfin_sw_breakpoint_from_kind);
 820   set_gdbarch_decr_pc_after_break (gdbarch, 2);
 821   set_gdbarch_frame_args_skip (gdbarch, 8);
 822   set_gdbarch_frame_align (gdbarch, bfin_frame_align);
 823
 824   /* Hook in ABI-specific overrides, if they have been registered.  */
 825   gdbarch_init_osabi (info, gdbarch);
 826
 827   dwarf2_append_unwinders (gdbarch);
 828
 829   frame_base_set_default (gdbarch, &bfin_frame_base);
 830
 831   frame_unwind_append_unwinder (gdbarch, &bfin_frame_unwind);
 832
 833   return gdbarch;
 834 }
 835
 836 void
 837 _initialize_bfin_tdep (void)
 838 {
 839   register_gdbarch_init (bfd_arch_bfin, bfin_gdbarch_init);
 840 }