gdb/bfin-tdep.c

   1 /* Target-dependent code for Analog Devices Blackfin processor, for GDB.
   2
   3    Copyright (C) 2005-2022 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   "bfin prologue",
 378   NORMAL_FRAME,
 379   default_frame_unwind_stop_reason,
 380   bfin_frame_this_id,
 381   bfin_frame_prev_register,
 382   NULL,
 383   default_frame_sniffer
 384 };
 385
 386 /* Check for "[--SP] = <reg>;" insns.  These are appear in function
 387    prologues to save misc registers onto the stack.  */
 388
 389 static int
 390 is_minus_minus_sp (int op)
 391 {
 392   op &= 0xFFC0;
 393
 394   if ((op == P_MINUS_SP1) || (op == P_MINUS_SP2)
 395       || (op == P_MINUS_SP3) || (op == P_MINUS_SP4))
 396     return 1;
 397
 398   return 0;
 399 }
 400
 401 /* Skip all the insns that appear in generated function prologues.  */
 402
 403 static CORE_ADDR
 404 bfin_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
 405 {
 406   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 407   int op = read_memory_unsigned_integer (pc, 2, byte_order);
 408   CORE_ADDR orig_pc = pc;
 409   int done = 0;
 410
 411   /* The new gcc prologue generates the register saves BEFORE the link
 412      or RETS saving instruction.
 413      So, our job is to stop either at those instructions or some upper
 414      limit saying there is no frame!  */
 415
 416   while (!done)
 417     {
 418       if (is_minus_minus_sp (op))
 419         {
 420           while (is_minus_minus_sp (op))
 421             {
 422               pc += 2;
 423               op = read_memory_unsigned_integer (pc, 2, byte_order);
 424             }
 425
 426           if (op == P_LINKAGE)
 427             pc += 4;
 428
 429           done = 1;
 430         }
 431       else if (op == P_LINKAGE)
 432         {
 433           pc += 4;
 434           done = 1;
 435         }
 436       else if (op == P_MINUS_MINUS_SP_EQ_RETS)
 437         {
 438           pc += 2;
 439           done = 1;
 440         }
 441       else if (op == P_RTS)
 442         {
 443           done = 1;
 444         }
 445       else if ((op >= P_JUMP_PREG_MIN && op <= P_JUMP_PREG_MAX)
 446                || (op >= P_JUMP_PC_PLUS_PREG_MIN
 447                    && op <= P_JUMP_PC_PLUS_PREG_MAX)
 448                || (op == P_JUMP_S_MIN && op <= P_JUMP_S_MAX))
 449         {
 450           done = 1;
 451         }
 452       else if (pc - orig_pc >= UPPER_LIMIT)
 453         {
 454           warning (_("Function Prologue not recognised; "
 455                      "pc will point to ENTRY_POINT of the function"));
 456           pc = orig_pc + 2;
 457           done = 1;
 458         }
 459       else
 460         {
 461           pc += 2; /* Not a terminating instruction go on.  */
 462           op = read_memory_unsigned_integer (pc, 2, byte_order);
 463         }
 464     }
 465
 466    /* TODO:
 467       Dwarf2 uses entry point value AFTER some register initializations.
 468       We should perhaps skip such asssignments as well (R6 = R1, ...).  */
 469
 470   return pc;
 471 }
 472
 473 /* Return the GDB type object for the "standard" data type of data in
 474    register N.  This should be void pointer for P0-P5, SP, FP;
 475    void pointer to function for PC; int otherwise.  */
 476
 477 static struct type *
 478 bfin_register_type (struct gdbarch *gdbarch, int regnum)
 479 {
 480   if ((regnum >= BFIN_P0_REGNUM && regnum <= BFIN_FP_REGNUM)
 481       || regnum == BFIN_USP_REGNUM)
 482     return builtin_type (gdbarch)->builtin_data_ptr;
 483
 484   if (regnum == BFIN_PC_REGNUM || regnum == BFIN_RETS_REGNUM
 485       || regnum == BFIN_RETI_REGNUM || regnum == BFIN_RETX_REGNUM
 486       || regnum == BFIN_RETN_REGNUM || regnum == BFIN_RETE_REGNUM
 487       || regnum == BFIN_LT0_REGNUM || regnum == BFIN_LB0_REGNUM
 488       || regnum == BFIN_LT1_REGNUM || regnum == BFIN_LB1_REGNUM)
 489     return builtin_type (gdbarch)->builtin_func_ptr;
 490
 491   return builtin_type (gdbarch)->builtin_int32;
 492 }
 493
 494 static CORE_ADDR
 495 bfin_push_dummy_call (struct gdbarch *gdbarch,
 496                       struct value *function,
 497                       struct regcache *regcache,
 498                       CORE_ADDR bp_addr,
 499                       int nargs,
 500                       struct value **args,
 501                       CORE_ADDR sp,
 502                       function_call_return_method return_method,
 503                       CORE_ADDR struct_addr)
 504 {
 505   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 506   int i;
 507   long reg_r0, reg_r1, reg_r2;
 508   int total_len = 0;
 509
 510   for (i = nargs - 1; i >= 0; i--)
 511     {
 512       struct type *value_type = value_enclosing_type (args[i]);
 513
 514       total_len += align_up (value_type->length (), 4);
 515     }
 516
 517   /* At least twelve bytes of stack space must be allocated for the function's
 518      arguments, even for functions that have less than 12 bytes of argument
 519      data.  */
 520
 521   if (total_len < 12)
 522     sp -= 12 - total_len;
 523
 524   /* Push arguments in reverse order.  */
 525
 526   for (i = nargs - 1; i >= 0; i--)
 527     {
 528       struct type *value_type = value_enclosing_type (args[i]);
 529       struct type *arg_type = check_typedef (value_type);
 530       int container_len = align_up (arg_type->length (), 4);
 531
 532       sp -= container_len;
 533       write_memory (sp, value_contents (args[i]).data (), container_len);
 534     }
 535
 536   /* Initialize R0, R1, and R2 to the first 3 words of parameters.  */
 537
 538   reg_r0 = read_memory_integer (sp, 4, byte_order);
 539   regcache_cooked_write_unsigned (regcache, BFIN_R0_REGNUM, reg_r0);
 540   reg_r1 = read_memory_integer (sp + 4, 4, byte_order);
 541   regcache_cooked_write_unsigned (regcache, BFIN_R1_REGNUM, reg_r1);
 542   reg_r2 = read_memory_integer (sp + 8, 4, byte_order);
 543   regcache_cooked_write_unsigned (regcache, BFIN_R2_REGNUM, reg_r2);
 544
 545   /* Store struct value address.  */
 546
 547   if (return_method == return_method_struct)
 548     regcache_cooked_write_unsigned (regcache, BFIN_P0_REGNUM, struct_addr);
 549
 550   /* Set the dummy return value to bp_addr.
 551      A dummy breakpoint will be setup to execute the call.  */
 552
 553   regcache_cooked_write_unsigned (regcache, BFIN_RETS_REGNUM, bp_addr);
 554
 555   /* Finally, update the stack pointer.  */
 556
 557   regcache_cooked_write_unsigned (regcache, BFIN_SP_REGNUM, sp);
 558
 559   return sp;
 560 }
 561
 562 /* Convert DWARF2 register number REG to the appropriate register number
 563    used by GDB.  */
 564
 565 static int
 566 bfin_reg_to_regnum (struct gdbarch *gdbarch, int reg)
 567 {
 568   if (reg < 0 || reg >= ARRAY_SIZE (map_gcc_gdb))
 569     return -1;
 570
 571   return map_gcc_gdb[reg];
 572 }
 573
 574 /* Implement the breakpoint_kind_from_pc gdbarch method.  */
 575
 576 static int
 577 bfin_breakpoint_kind_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr)
 578 {
 579   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 580   unsigned short iw;
 581
 582   iw = read_memory_unsigned_integer (*pcptr, 2, byte_order);
 583
 584   if ((iw & 0xf000) >= 0xc000)
 585     /* 32-bit instruction.  */
 586     return 4;
 587   else
 588     return 2;
 589 }
 590
 591 /* Implement the sw_breakpoint_from_kind gdbarch method.  */
 592
 593 static const gdb_byte *
 594 bfin_sw_breakpoint_from_kind (struct gdbarch *gdbarch, int kind, int *size)
 595 {
 596   static unsigned char bfin_breakpoint[] = {0xa1, 0x00, 0x00, 0x00};
 597   static unsigned char bfin_sim_breakpoint[] = {0x25, 0x00, 0x00, 0x00};
 598
 599   *size = kind;
 600
 601   if (strcmp (target_shortname (), "sim") == 0)
 602     return bfin_sim_breakpoint;
 603   else
 604     return bfin_breakpoint;
 605 }
 606
 607 static void
 608 bfin_extract_return_value (struct type *type,
 609                            struct regcache *regs,
 610                            gdb_byte *dst)
 611 {
 612   struct gdbarch *gdbarch = regs->arch ();
 613   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
 614   bfd_byte *valbuf = dst;
 615   int len = type->length ();
 616   ULONGEST tmp;
 617   int regno = BFIN_R0_REGNUM;
 618
 619   gdb_assert (len <= 8);
 620
 621   while (len > 0)
 622     {
 623       regcache_cooked_read_unsigned (regs, regno++, &tmp);
 624       store_unsigned_integer (valbuf, (len > 4 ? 4 : len), byte_order, tmp);
 625       len -= 4;
 626       valbuf += 4;
 627     }
 628 }
 629
 630 /* Write into appropriate registers a function return value of type
 631    TYPE, given in virtual format.  */
 632
 633 static void
 634 bfin_store_return_value (struct type *type,
 635                          struct regcache *regs,
 636                          const gdb_byte *src)
 637 {
 638   const bfd_byte *valbuf = src;
 639
 640   /* Integral values greater than one word are stored in consecutive
 641      registers starting with R0.  This will always be a multiple of
 642      the register size.  */
 643
 644   int len = type->length ();
 645   int regno = BFIN_R0_REGNUM;
 646
 647   gdb_assert (len <= 8);
 648
 649   while (len > 0)
 650     {
 651       regs->cooked_write (regno++, valbuf);
 652       len -= 4;
 653       valbuf += 4;
 654     }
 655 }
 656
 657 /* Determine, for architecture GDBARCH, how a return value of TYPE
 658    should be returned.  If it is supposed to be returned in registers,
 659    and READBUF is nonzero, read the appropriate value from REGCACHE,
 660    and copy it into READBUF.  If WRITEBUF is nonzero, write the value
 661    from WRITEBUF into REGCACHE.  */
 662
 663 static enum return_value_convention
 664 bfin_return_value (struct gdbarch *gdbarch,
 665                    struct value *function,
 666                    struct type *type,
 667                    struct regcache *regcache,
 668                    gdb_byte *readbuf,
 669                    const gdb_byte *writebuf)
 670 {
 671   if (type->length () > 8)
 672     return RETURN_VALUE_STRUCT_CONVENTION;
 673
 674   if (readbuf)
 675     bfin_extract_return_value (type, regcache, readbuf);
 676
 677   if (writebuf)
 678     bfin_store_return_value (type, regcache, writebuf);
 679
 680   return RETURN_VALUE_REGISTER_CONVENTION;
 681 }
 682
 683 /* Return the BFIN register name corresponding to register I.  */
 684
 685 static const char *
 686 bfin_register_name (struct gdbarch *gdbarch, int i)
 687 {
 688   return bfin_register_name_strings[i];
 689 }
 690
 691 static enum register_status
 692 bfin_pseudo_register_read (struct gdbarch *gdbarch, readable_regcache *regcache,
 693                            int regnum, gdb_byte *buffer)
 694 {
 695   gdb_byte buf[BFIN_MAX_REGISTER_SIZE];
 696   enum register_status status;
 697
 698   if (regnum != BFIN_CC_REGNUM)
 699     internal_error (__FILE__, __LINE__,
 700                     _("invalid register number %d"), regnum);
 701
 702   /* Extract the CC bit from the ASTAT register.  */
 703   status = regcache->raw_read (BFIN_ASTAT_REGNUM, buf);
 704   if (status == REG_VALID)
 705     {
 706       buffer[1] = buffer[2] = buffer[3] = 0;
 707       buffer[0] = !!(buf[0] & ASTAT_CC);
 708     }
 709   return status;
 710 }
 711
 712 static void
 713 bfin_pseudo_register_write (struct gdbarch *gdbarch, struct regcache *regcache,
 714                             int regnum, const gdb_byte *buffer)
 715 {
 716   gdb_byte buf[BFIN_MAX_REGISTER_SIZE];
 717
 718   if (regnum != BFIN_CC_REGNUM)
 719     internal_error (__FILE__, __LINE__,
 720                     _("invalid register number %d"), regnum);
 721
 722   /* Overlay the CC bit in the ASTAT register.  */
 723   regcache->raw_read (BFIN_ASTAT_REGNUM, buf);
 724   buf[0] = (buf[0] & ~ASTAT_CC) | ((buffer[0] & 1) << ASTAT_CC_POS);
 725   regcache->raw_write (BFIN_ASTAT_REGNUM, buf);
 726 }
 727
 728 static CORE_ADDR
 729 bfin_frame_base_address (struct frame_info *this_frame, void **this_cache)
 730 {
 731   struct bfin_frame_cache *cache = bfin_frame_cache (this_frame, this_cache);
 732
 733   return cache->base;
 734 }
 735
 736 static CORE_ADDR
 737 bfin_frame_local_address (struct frame_info *this_frame, void **this_cache)
 738 {
 739   struct bfin_frame_cache *cache = bfin_frame_cache (this_frame, this_cache);
 740
 741   return cache->base - 4;
 742 }
 743
 744 static CORE_ADDR
 745 bfin_frame_args_address (struct frame_info *this_frame, void **this_cache)
 746 {
 747   struct bfin_frame_cache *cache = bfin_frame_cache (this_frame, this_cache);
 748
 749   return cache->base + 8;
 750 }
 751
 752 static const struct frame_base bfin_frame_base =
 753 {
 754   &bfin_frame_unwind,
 755   bfin_frame_base_address,
 756   bfin_frame_local_address,
 757   bfin_frame_args_address
 758 };
 759
 760 static CORE_ADDR
 761 bfin_frame_align (struct gdbarch *gdbarch, CORE_ADDR address)
 762 {
 763   return align_down (address, 4);
 764 }
 765
 766 enum bfin_abi
 767 bfin_abi (struct gdbarch *gdbarch)
 768 {
 769   bfin_gdbarch_tdep *tdep = gdbarch_tdep<bfin_gdbarch_tdep> (gdbarch);
 770   return tdep->bfin_abi;
 771 }
 772
 773 /* Initialize the current architecture based on INFO.  If possible,
 774    re-use an architecture from ARCHES, which is a list of
 775    architectures already created during this debugging session.
 776
 777    Called e.g. at program startup, when reading a core file, and when
 778    reading a binary file.  */
 779
 780 static struct gdbarch *
 781 bfin_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 782 {
 783   struct gdbarch *gdbarch;
 784   enum bfin_abi abi;
 785
 786   abi = BFIN_ABI_FLAT;
 787
 788   /* If there is already a candidate, use it.  */
 789
 790   for (arches = gdbarch_list_lookup_by_info (arches, &info);
 791        arches != NULL;
 792        arches = gdbarch_list_lookup_by_info (arches->next, &info))
 793     {
 794       bfin_gdbarch_tdep *tdep
 795         = gdbarch_tdep<bfin_gdbarch_tdep> (arches->gdbarch);
 796
 797       if (tdep->bfin_abi != abi)
 798         continue;
 799
 800       return arches->gdbarch;
 801     }
 802
 803   bfin_gdbarch_tdep *tdep = new bfin_gdbarch_tdep;
 804   gdbarch = gdbarch_alloc (&info, tdep);
 805
 806   tdep->bfin_abi = abi;
 807
 808   set_gdbarch_num_regs (gdbarch, BFIN_NUM_REGS);
 809   set_gdbarch_pseudo_register_read (gdbarch, bfin_pseudo_register_read);
 810   set_gdbarch_pseudo_register_write (gdbarch, bfin_pseudo_register_write);
 811   set_gdbarch_num_pseudo_regs (gdbarch, BFIN_NUM_PSEUDO_REGS);
 812   set_gdbarch_sp_regnum (gdbarch, BFIN_SP_REGNUM);
 813   set_gdbarch_pc_regnum (gdbarch, BFIN_PC_REGNUM);
 814   set_gdbarch_ps_regnum (gdbarch, BFIN_ASTAT_REGNUM);
 815   set_gdbarch_dwarf2_reg_to_regnum (gdbarch, bfin_reg_to_regnum);
 816   set_gdbarch_register_name (gdbarch, bfin_register_name);
 817   set_gdbarch_register_type (gdbarch, bfin_register_type);
 818   set_gdbarch_push_dummy_call (gdbarch, bfin_push_dummy_call);
 819   set_gdbarch_believe_pcc_promotion (gdbarch, 1);
 820   set_gdbarch_return_value (gdbarch, bfin_return_value);
 821   set_gdbarch_skip_prologue (gdbarch, bfin_skip_prologue);
 822   set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
 823   set_gdbarch_breakpoint_kind_from_pc (gdbarch, bfin_breakpoint_kind_from_pc);
 824   set_gdbarch_sw_breakpoint_from_kind (gdbarch, bfin_sw_breakpoint_from_kind);
 825   set_gdbarch_decr_pc_after_break (gdbarch, 2);
 826   set_gdbarch_frame_args_skip (gdbarch, 8);
 827   set_gdbarch_frame_align (gdbarch, bfin_frame_align);
 828
 829   /* Hook in ABI-specific overrides, if they have been registered.  */
 830   gdbarch_init_osabi (info, gdbarch);
 831
 832   dwarf2_append_unwinders (gdbarch);
 833
 834   frame_base_set_default (gdbarch, &bfin_frame_base);
 835
 836   frame_unwind_append_unwinder (gdbarch, &bfin_frame_unwind);
 837
 838   return gdbarch;
 839 }
 840
 841 void _initialize_bfin_tdep ();
 842 void
 843 _initialize_bfin_tdep ()
 844 {
 845   gdbarch_register (bfd_arch_bfin, bfin_gdbarch_init);
 846 }