| 1 | /* Target-dependent code for the Motorola 68000 series. |
| 2 | |
| 3 | Copyright (C) 1990-2021 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include "defs.h" |
| 21 | #include "dwarf2/frame.h" |
| 22 | #include "frame.h" |
| 23 | #include "frame-base.h" |
| 24 | #include "frame-unwind.h" |
| 25 | #include "gdbtypes.h" |
| 26 | #include "symtab.h" |
| 27 | #include "gdbcore.h" |
| 28 | #include "value.h" |
| 29 | #include "inferior.h" |
| 30 | #include "regcache.h" |
| 31 | #include "arch-utils.h" |
| 32 | #include "osabi.h" |
| 33 | #include "dis-asm.h" |
| 34 | #include "target-descriptions.h" |
| 35 | #include "floatformat.h" |
| 36 | #include "target-float.h" |
| 37 | #include "elf-bfd.h" |
| 38 | #include "elf/m68k.h" |
| 39 | |
| 40 | #include "m68k-tdep.h" |
| 41 | \f |
| 42 | |
| 43 | #define P_LINKL_FP 0x480e |
| 44 | #define P_LINKW_FP 0x4e56 |
| 45 | #define P_PEA_FP 0x4856 |
| 46 | #define P_MOVEAL_SP_FP 0x2c4f |
| 47 | #define P_ADDAW_SP 0xdefc |
| 48 | #define P_ADDAL_SP 0xdffc |
| 49 | #define P_SUBQW_SP 0x514f |
| 50 | #define P_SUBQL_SP 0x518f |
| 51 | #define P_LEA_SP_SP 0x4fef |
| 52 | #define P_LEA_PC_A5 0x4bfb0170 |
| 53 | #define P_FMOVEMX_SP 0xf227 |
| 54 | #define P_MOVEL_SP 0x2f00 |
| 55 | #define P_MOVEML_SP 0x48e7 |
| 56 | |
| 57 | /* Offset from SP to first arg on stack at first instruction of a function. */ |
| 58 | #define SP_ARG0 (1 * 4) |
| 59 | |
| 60 | #if !defined (BPT_VECTOR) |
| 61 | #define BPT_VECTOR 0xf |
| 62 | #endif |
| 63 | |
| 64 | constexpr gdb_byte m68k_break_insn[] = {0x4e, (0x40 | BPT_VECTOR)}; |
| 65 | |
| 66 | typedef BP_MANIPULATION (m68k_break_insn) m68k_breakpoint; |
| 67 | \f |
| 68 | |
| 69 | /* Construct types for ISA-specific registers. */ |
| 70 | static struct type * |
| 71 | m68k_ps_type (struct gdbarch *gdbarch) |
| 72 | { |
| 73 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 74 | |
| 75 | if (!tdep->m68k_ps_type) |
| 76 | { |
| 77 | struct type *type; |
| 78 | |
| 79 | type = arch_flags_type (gdbarch, "builtin_type_m68k_ps", 32); |
| 80 | append_flags_type_flag (type, 0, "C"); |
| 81 | append_flags_type_flag (type, 1, "V"); |
| 82 | append_flags_type_flag (type, 2, "Z"); |
| 83 | append_flags_type_flag (type, 3, "N"); |
| 84 | append_flags_type_flag (type, 4, "X"); |
| 85 | append_flags_type_flag (type, 8, "I0"); |
| 86 | append_flags_type_flag (type, 9, "I1"); |
| 87 | append_flags_type_flag (type, 10, "I2"); |
| 88 | append_flags_type_flag (type, 12, "M"); |
| 89 | append_flags_type_flag (type, 13, "S"); |
| 90 | append_flags_type_flag (type, 14, "T0"); |
| 91 | append_flags_type_flag (type, 15, "T1"); |
| 92 | |
| 93 | tdep->m68k_ps_type = type; |
| 94 | } |
| 95 | |
| 96 | return tdep->m68k_ps_type; |
| 97 | } |
| 98 | |
| 99 | static struct type * |
| 100 | m68881_ext_type (struct gdbarch *gdbarch) |
| 101 | { |
| 102 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 103 | |
| 104 | if (!tdep->m68881_ext_type) |
| 105 | tdep->m68881_ext_type |
| 106 | = arch_float_type (gdbarch, -1, "builtin_type_m68881_ext", |
| 107 | floatformats_m68881_ext); |
| 108 | |
| 109 | return tdep->m68881_ext_type; |
| 110 | } |
| 111 | |
| 112 | /* Return the GDB type object for the "standard" data type of data in |
| 113 | register N. This should be int for D0-D7, SR, FPCONTROL and |
| 114 | FPSTATUS, long double for FP0-FP7, and void pointer for all others |
| 115 | (A0-A7, PC, FPIADDR). Note, for registers which contain |
| 116 | addresses return pointer to void, not pointer to char, because we |
| 117 | don't want to attempt to print the string after printing the |
| 118 | address. */ |
| 119 | |
| 120 | static struct type * |
| 121 | m68k_register_type (struct gdbarch *gdbarch, int regnum) |
| 122 | { |
| 123 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 124 | |
| 125 | if (tdep->fpregs_present) |
| 126 | { |
| 127 | if (regnum >= gdbarch_fp0_regnum (gdbarch) |
| 128 | && regnum <= gdbarch_fp0_regnum (gdbarch) + 7) |
| 129 | { |
| 130 | if (tdep->flavour == m68k_coldfire_flavour) |
| 131 | return builtin_type (gdbarch)->builtin_double; |
| 132 | else |
| 133 | return m68881_ext_type (gdbarch); |
| 134 | } |
| 135 | |
| 136 | if (regnum == M68K_FPI_REGNUM) |
| 137 | return builtin_type (gdbarch)->builtin_func_ptr; |
| 138 | |
| 139 | if (regnum == M68K_FPC_REGNUM || regnum == M68K_FPS_REGNUM) |
| 140 | return builtin_type (gdbarch)->builtin_int32; |
| 141 | } |
| 142 | else |
| 143 | { |
| 144 | if (regnum >= M68K_FP0_REGNUM && regnum <= M68K_FPI_REGNUM) |
| 145 | return builtin_type (gdbarch)->builtin_int0; |
| 146 | } |
| 147 | |
| 148 | if (regnum == gdbarch_pc_regnum (gdbarch)) |
| 149 | return builtin_type (gdbarch)->builtin_func_ptr; |
| 150 | |
| 151 | if (regnum >= M68K_A0_REGNUM && regnum <= M68K_A0_REGNUM + 7) |
| 152 | return builtin_type (gdbarch)->builtin_data_ptr; |
| 153 | |
| 154 | if (regnum == M68K_PS_REGNUM) |
| 155 | return m68k_ps_type (gdbarch); |
| 156 | |
| 157 | return builtin_type (gdbarch)->builtin_int32; |
| 158 | } |
| 159 | |
| 160 | static const char * const m68k_register_names[] = { |
| 161 | "d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7", |
| 162 | "a0", "a1", "a2", "a3", "a4", "a5", "fp", "sp", |
| 163 | "ps", "pc", |
| 164 | "fp0", "fp1", "fp2", "fp3", "fp4", "fp5", "fp6", "fp7", |
| 165 | "fpcontrol", "fpstatus", "fpiaddr" |
| 166 | }; |
| 167 | |
| 168 | /* Function: m68k_register_name |
| 169 | Returns the name of the standard m68k register regnum. */ |
| 170 | |
| 171 | static const char * |
| 172 | m68k_register_name (struct gdbarch *gdbarch, int regnum) |
| 173 | { |
| 174 | if (regnum < 0 || regnum >= ARRAY_SIZE (m68k_register_names)) |
| 175 | internal_error (__FILE__, __LINE__, |
| 176 | _("m68k_register_name: illegal register number %d"), |
| 177 | regnum); |
| 178 | else if (regnum >= M68K_FP0_REGNUM && regnum <= M68K_FPI_REGNUM |
| 179 | && gdbarch_tdep (gdbarch)->fpregs_present == 0) |
| 180 | return ""; |
| 181 | else |
| 182 | return m68k_register_names[regnum]; |
| 183 | } |
| 184 | \f |
| 185 | /* Return nonzero if a value of type TYPE stored in register REGNUM |
| 186 | needs any special handling. */ |
| 187 | |
| 188 | static int |
| 189 | m68k_convert_register_p (struct gdbarch *gdbarch, |
| 190 | int regnum, struct type *type) |
| 191 | { |
| 192 | if (!gdbarch_tdep (gdbarch)->fpregs_present) |
| 193 | return 0; |
| 194 | return (regnum >= M68K_FP0_REGNUM && regnum <= M68K_FP0_REGNUM + 7 |
| 195 | /* We only support floating-point values. */ |
| 196 | && type->code () == TYPE_CODE_FLT |
| 197 | && type != register_type (gdbarch, M68K_FP0_REGNUM)); |
| 198 | } |
| 199 | |
| 200 | /* Read a value of type TYPE from register REGNUM in frame FRAME, and |
| 201 | return its contents in TO. */ |
| 202 | |
| 203 | static int |
| 204 | m68k_register_to_value (struct frame_info *frame, int regnum, |
| 205 | struct type *type, gdb_byte *to, |
| 206 | int *optimizedp, int *unavailablep) |
| 207 | { |
| 208 | struct gdbarch *gdbarch = get_frame_arch (frame); |
| 209 | gdb_byte from[M68K_MAX_REGISTER_SIZE]; |
| 210 | struct type *fpreg_type = register_type (gdbarch, M68K_FP0_REGNUM); |
| 211 | |
| 212 | gdb_assert (type->code () == TYPE_CODE_FLT); |
| 213 | |
| 214 | /* Convert to TYPE. */ |
| 215 | if (!get_frame_register_bytes (frame, regnum, 0, |
| 216 | gdb::make_array_view (from, |
| 217 | register_size (gdbarch, |
| 218 | regnum)), |
| 219 | optimizedp, unavailablep)) |
| 220 | return 0; |
| 221 | |
| 222 | target_float_convert (from, fpreg_type, to, type); |
| 223 | *optimizedp = *unavailablep = 0; |
| 224 | return 1; |
| 225 | } |
| 226 | |
| 227 | /* Write the contents FROM of a value of type TYPE into register |
| 228 | REGNUM in frame FRAME. */ |
| 229 | |
| 230 | static void |
| 231 | m68k_value_to_register (struct frame_info *frame, int regnum, |
| 232 | struct type *type, const gdb_byte *from) |
| 233 | { |
| 234 | gdb_byte to[M68K_MAX_REGISTER_SIZE]; |
| 235 | struct type *fpreg_type = register_type (get_frame_arch (frame), |
| 236 | M68K_FP0_REGNUM); |
| 237 | |
| 238 | /* We only support floating-point values. */ |
| 239 | if (type->code () != TYPE_CODE_FLT) |
| 240 | { |
| 241 | warning (_("Cannot convert non-floating-point type " |
| 242 | "to floating-point register value.")); |
| 243 | return; |
| 244 | } |
| 245 | |
| 246 | /* Convert from TYPE. */ |
| 247 | target_float_convert (from, type, to, fpreg_type); |
| 248 | put_frame_register (frame, regnum, to); |
| 249 | } |
| 250 | |
| 251 | \f |
| 252 | /* There is a fair number of calling conventions that are in somewhat |
| 253 | wide use. The 68000/08/10 don't support an FPU, not even as a |
| 254 | coprocessor. All function return values are stored in %d0/%d1. |
| 255 | Structures are returned in a static buffer, a pointer to which is |
| 256 | returned in %d0. This means that functions returning a structure |
| 257 | are not re-entrant. To avoid this problem some systems use a |
| 258 | convention where the caller passes a pointer to a buffer in %a1 |
| 259 | where the return values is to be stored. This convention is the |
| 260 | default, and is implemented in the function m68k_return_value. |
| 261 | |
| 262 | The 68020/030/040/060 do support an FPU, either as a coprocessor |
| 263 | (68881/2) or built-in (68040/68060). That's why System V release 4 |
| 264 | (SVR4) introduces a new calling convention specified by the SVR4 |
| 265 | psABI. Integer values are returned in %d0/%d1, pointer return |
| 266 | values in %a0 and floating values in %fp0. When calling functions |
| 267 | returning a structure the caller should pass a pointer to a buffer |
| 268 | for the return value in %a0. This convention is implemented in the |
| 269 | function m68k_svr4_return_value, and by appropriately setting the |
| 270 | struct_value_regnum member of `struct gdbarch_tdep'. |
| 271 | |
| 272 | GNU/Linux returns values in the same way as SVR4 does, but uses %a1 |
| 273 | for passing the structure return value buffer. |
| 274 | |
| 275 | GCC can also generate code where small structures are returned in |
| 276 | %d0/%d1 instead of in memory by using -freg-struct-return. This is |
| 277 | the default on NetBSD a.out, OpenBSD and GNU/Linux and several |
| 278 | embedded systems. This convention is implemented by setting the |
| 279 | struct_return member of `struct gdbarch_tdep' to reg_struct_return. |
| 280 | |
| 281 | GCC also has an "embedded" ABI. This works like the SVR4 ABI, |
| 282 | except that pointers are returned in %D0. This is implemented by |
| 283 | setting the pointer_result_regnum member of `struct gdbarch_tdep' |
| 284 | as appropriate. */ |
| 285 | |
| 286 | /* Read a function return value of TYPE from REGCACHE, and copy that |
| 287 | into VALBUF. */ |
| 288 | |
| 289 | static void |
| 290 | m68k_extract_return_value (struct type *type, struct regcache *regcache, |
| 291 | gdb_byte *valbuf) |
| 292 | { |
| 293 | int len = TYPE_LENGTH (type); |
| 294 | gdb_byte buf[M68K_MAX_REGISTER_SIZE]; |
| 295 | |
| 296 | if (type->code () == TYPE_CODE_PTR && len == 4) |
| 297 | { |
| 298 | struct gdbarch *gdbarch = regcache->arch (); |
| 299 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 300 | regcache->raw_read (tdep->pointer_result_regnum, valbuf); |
| 301 | } |
| 302 | else if (len <= 4) |
| 303 | { |
| 304 | regcache->raw_read (M68K_D0_REGNUM, buf); |
| 305 | memcpy (valbuf, buf + (4 - len), len); |
| 306 | } |
| 307 | else if (len <= 8) |
| 308 | { |
| 309 | regcache->raw_read (M68K_D0_REGNUM, buf); |
| 310 | memcpy (valbuf, buf + (8 - len), len - 4); |
| 311 | regcache->raw_read (M68K_D1_REGNUM, valbuf + (len - 4)); |
| 312 | } |
| 313 | else |
| 314 | internal_error (__FILE__, __LINE__, |
| 315 | _("Cannot extract return value of %d bytes long."), len); |
| 316 | } |
| 317 | |
| 318 | static void |
| 319 | m68k_svr4_extract_return_value (struct type *type, struct regcache *regcache, |
| 320 | gdb_byte *valbuf) |
| 321 | { |
| 322 | gdb_byte buf[M68K_MAX_REGISTER_SIZE]; |
| 323 | struct gdbarch *gdbarch = regcache->arch (); |
| 324 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 325 | |
| 326 | if (tdep->float_return && type->code () == TYPE_CODE_FLT) |
| 327 | { |
| 328 | struct type *fpreg_type = register_type (gdbarch, M68K_FP0_REGNUM); |
| 329 | regcache->raw_read (M68K_FP0_REGNUM, buf); |
| 330 | target_float_convert (buf, fpreg_type, valbuf, type); |
| 331 | } |
| 332 | else |
| 333 | m68k_extract_return_value (type, regcache, valbuf); |
| 334 | } |
| 335 | |
| 336 | /* Write a function return value of TYPE from VALBUF into REGCACHE. */ |
| 337 | |
| 338 | static void |
| 339 | m68k_store_return_value (struct type *type, struct regcache *regcache, |
| 340 | const gdb_byte *valbuf) |
| 341 | { |
| 342 | int len = TYPE_LENGTH (type); |
| 343 | |
| 344 | if (type->code () == TYPE_CODE_PTR && len == 4) |
| 345 | { |
| 346 | struct gdbarch *gdbarch = regcache->arch (); |
| 347 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 348 | regcache->raw_write (tdep->pointer_result_regnum, valbuf); |
| 349 | /* gdb historically also set D0 in the SVR4 case. */ |
| 350 | if (tdep->pointer_result_regnum != M68K_D0_REGNUM) |
| 351 | regcache->raw_write (M68K_D0_REGNUM, valbuf); |
| 352 | } |
| 353 | else if (len <= 4) |
| 354 | regcache->raw_write_part (M68K_D0_REGNUM, 4 - len, len, valbuf); |
| 355 | else if (len <= 8) |
| 356 | { |
| 357 | regcache->raw_write_part (M68K_D0_REGNUM, 8 - len, len - 4, valbuf); |
| 358 | regcache->raw_write (M68K_D1_REGNUM, valbuf + (len - 4)); |
| 359 | } |
| 360 | else |
| 361 | internal_error (__FILE__, __LINE__, |
| 362 | _("Cannot store return value of %d bytes long."), len); |
| 363 | } |
| 364 | |
| 365 | static void |
| 366 | m68k_svr4_store_return_value (struct type *type, struct regcache *regcache, |
| 367 | const gdb_byte *valbuf) |
| 368 | { |
| 369 | struct gdbarch *gdbarch = regcache->arch (); |
| 370 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 371 | |
| 372 | if (tdep->float_return && type->code () == TYPE_CODE_FLT) |
| 373 | { |
| 374 | struct type *fpreg_type = register_type (gdbarch, M68K_FP0_REGNUM); |
| 375 | gdb_byte buf[M68K_MAX_REGISTER_SIZE]; |
| 376 | target_float_convert (valbuf, type, buf, fpreg_type); |
| 377 | regcache->raw_write (M68K_FP0_REGNUM, buf); |
| 378 | } |
| 379 | else |
| 380 | m68k_store_return_value (type, regcache, valbuf); |
| 381 | } |
| 382 | |
| 383 | /* Return non-zero if TYPE, which is assumed to be a structure, union or |
| 384 | complex type, should be returned in registers for architecture |
| 385 | GDBARCH. */ |
| 386 | |
| 387 | static int |
| 388 | m68k_reg_struct_return_p (struct gdbarch *gdbarch, struct type *type) |
| 389 | { |
| 390 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 391 | enum type_code code = type->code (); |
| 392 | int len = TYPE_LENGTH (type); |
| 393 | |
| 394 | gdb_assert (code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION |
| 395 | || code == TYPE_CODE_COMPLEX || code == TYPE_CODE_ARRAY); |
| 396 | |
| 397 | if (tdep->struct_return == pcc_struct_return) |
| 398 | return 0; |
| 399 | |
| 400 | const bool is_vector = code == TYPE_CODE_ARRAY && type->is_vector (); |
| 401 | |
| 402 | if (is_vector |
| 403 | && check_typedef (TYPE_TARGET_TYPE (type))->code () == TYPE_CODE_FLT) |
| 404 | return 0; |
| 405 | |
| 406 | /* According to m68k_return_in_memory in the m68k GCC back-end, |
| 407 | strange things happen for small aggregate types. Aggregate types |
| 408 | with only one component are always returned like the type of the |
| 409 | component. Aggregate types whose size is 2, 4, or 8 are returned |
| 410 | in registers if their natural alignment is at least 16 bits. |
| 411 | |
| 412 | We reject vectors here, as experimentally this gives the correct |
| 413 | answer. */ |
| 414 | if (!is_vector && (len == 2 || len == 4 || len == 8)) |
| 415 | return type_align (type) >= 2; |
| 416 | |
| 417 | return (len == 1 || len == 2 || len == 4 || len == 8); |
| 418 | } |
| 419 | |
| 420 | /* Determine, for architecture GDBARCH, how a return value of TYPE |
| 421 | should be returned. If it is supposed to be returned in registers, |
| 422 | and READBUF is non-zero, read the appropriate value from REGCACHE, |
| 423 | and copy it into READBUF. If WRITEBUF is non-zero, write the value |
| 424 | from WRITEBUF into REGCACHE. */ |
| 425 | |
| 426 | static enum return_value_convention |
| 427 | m68k_return_value (struct gdbarch *gdbarch, struct value *function, |
| 428 | struct type *type, struct regcache *regcache, |
| 429 | gdb_byte *readbuf, const gdb_byte *writebuf) |
| 430 | { |
| 431 | enum type_code code = type->code (); |
| 432 | |
| 433 | /* GCC returns a `long double' in memory too. */ |
| 434 | if (((code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION |
| 435 | || code == TYPE_CODE_COMPLEX || code == TYPE_CODE_ARRAY) |
| 436 | && !m68k_reg_struct_return_p (gdbarch, type)) |
| 437 | || (code == TYPE_CODE_FLT && TYPE_LENGTH (type) == 12)) |
| 438 | { |
| 439 | /* The default on m68k is to return structures in static memory. |
| 440 | Consequently a function must return the address where we can |
| 441 | find the return value. */ |
| 442 | |
| 443 | if (readbuf) |
| 444 | { |
| 445 | ULONGEST addr; |
| 446 | |
| 447 | regcache_raw_read_unsigned (regcache, M68K_D0_REGNUM, &addr); |
| 448 | read_memory (addr, readbuf, TYPE_LENGTH (type)); |
| 449 | } |
| 450 | |
| 451 | return RETURN_VALUE_ABI_RETURNS_ADDRESS; |
| 452 | } |
| 453 | |
| 454 | if (readbuf) |
| 455 | m68k_extract_return_value (type, regcache, readbuf); |
| 456 | if (writebuf) |
| 457 | m68k_store_return_value (type, regcache, writebuf); |
| 458 | |
| 459 | return RETURN_VALUE_REGISTER_CONVENTION; |
| 460 | } |
| 461 | |
| 462 | static enum return_value_convention |
| 463 | m68k_svr4_return_value (struct gdbarch *gdbarch, struct value *function, |
| 464 | struct type *type, struct regcache *regcache, |
| 465 | gdb_byte *readbuf, const gdb_byte *writebuf) |
| 466 | { |
| 467 | enum type_code code = type->code (); |
| 468 | |
| 469 | /* Aggregates with a single member are always returned like their |
| 470 | sole element. */ |
| 471 | if ((code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION) |
| 472 | && type->num_fields () == 1) |
| 473 | { |
| 474 | type = check_typedef (type->field (0).type ()); |
| 475 | return m68k_svr4_return_value (gdbarch, function, type, regcache, |
| 476 | readbuf, writebuf); |
| 477 | } |
| 478 | |
| 479 | if (((code == TYPE_CODE_STRUCT || code == TYPE_CODE_UNION |
| 480 | || code == TYPE_CODE_COMPLEX || code == TYPE_CODE_ARRAY) |
| 481 | && !m68k_reg_struct_return_p (gdbarch, type)) |
| 482 | /* GCC may return a `long double' in memory too. */ |
| 483 | || (!gdbarch_tdep (gdbarch)->float_return |
| 484 | && code == TYPE_CODE_FLT |
| 485 | && TYPE_LENGTH (type) == 12)) |
| 486 | { |
| 487 | /* The System V ABI says that: |
| 488 | |
| 489 | "A function returning a structure or union also sets %a0 to |
| 490 | the value it finds in %a0. Thus when the caller receives |
| 491 | control again, the address of the returned object resides in |
| 492 | register %a0." |
| 493 | |
| 494 | So the ABI guarantees that we can always find the return |
| 495 | value just after the function has returned. |
| 496 | |
| 497 | However, GCC also implements the "embedded" ABI. That ABI |
| 498 | does not preserve %a0 across calls, but does write the value |
| 499 | back to %d0. */ |
| 500 | |
| 501 | if (readbuf) |
| 502 | { |
| 503 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 504 | ULONGEST addr; |
| 505 | |
| 506 | regcache_raw_read_unsigned (regcache, tdep->pointer_result_regnum, |
| 507 | &addr); |
| 508 | read_memory (addr, readbuf, TYPE_LENGTH (type)); |
| 509 | } |
| 510 | |
| 511 | return RETURN_VALUE_ABI_RETURNS_ADDRESS; |
| 512 | } |
| 513 | |
| 514 | if (readbuf) |
| 515 | m68k_svr4_extract_return_value (type, regcache, readbuf); |
| 516 | if (writebuf) |
| 517 | m68k_svr4_store_return_value (type, regcache, writebuf); |
| 518 | |
| 519 | return RETURN_VALUE_REGISTER_CONVENTION; |
| 520 | } |
| 521 | \f |
| 522 | |
| 523 | /* Always align the frame to a 4-byte boundary. This is required on |
| 524 | coldfire and harmless on the rest. */ |
| 525 | |
| 526 | static CORE_ADDR |
| 527 | m68k_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp) |
| 528 | { |
| 529 | /* Align the stack to four bytes. */ |
| 530 | return sp & ~3; |
| 531 | } |
| 532 | |
| 533 | static CORE_ADDR |
| 534 | m68k_push_dummy_call (struct gdbarch *gdbarch, struct value *function, |
| 535 | struct regcache *regcache, CORE_ADDR bp_addr, int nargs, |
| 536 | struct value **args, CORE_ADDR sp, |
| 537 | function_call_return_method return_method, |
| 538 | CORE_ADDR struct_addr) |
| 539 | { |
| 540 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 541 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 542 | gdb_byte buf[4]; |
| 543 | int i; |
| 544 | |
| 545 | /* Push arguments in reverse order. */ |
| 546 | for (i = nargs - 1; i >= 0; i--) |
| 547 | { |
| 548 | struct type *value_type = value_enclosing_type (args[i]); |
| 549 | int len = TYPE_LENGTH (value_type); |
| 550 | int container_len = (len + 3) & ~3; |
| 551 | int offset; |
| 552 | |
| 553 | /* Non-scalars bigger than 4 bytes are left aligned, others are |
| 554 | right aligned. */ |
| 555 | if ((value_type->code () == TYPE_CODE_STRUCT |
| 556 | || value_type->code () == TYPE_CODE_UNION |
| 557 | || value_type->code () == TYPE_CODE_ARRAY) |
| 558 | && len > 4) |
| 559 | offset = 0; |
| 560 | else |
| 561 | offset = container_len - len; |
| 562 | sp -= container_len; |
| 563 | write_memory (sp + offset, value_contents_all (args[i]), len); |
| 564 | } |
| 565 | |
| 566 | /* Store struct value address. */ |
| 567 | if (return_method == return_method_struct) |
| 568 | { |
| 569 | store_unsigned_integer (buf, 4, byte_order, struct_addr); |
| 570 | regcache->cooked_write (tdep->struct_value_regnum, buf); |
| 571 | } |
| 572 | |
| 573 | /* Store return address. */ |
| 574 | sp -= 4; |
| 575 | store_unsigned_integer (buf, 4, byte_order, bp_addr); |
| 576 | write_memory (sp, buf, 4); |
| 577 | |
| 578 | /* Finally, update the stack pointer... */ |
| 579 | store_unsigned_integer (buf, 4, byte_order, sp); |
| 580 | regcache->cooked_write (M68K_SP_REGNUM, buf); |
| 581 | |
| 582 | /* ...and fake a frame pointer. */ |
| 583 | regcache->cooked_write (M68K_FP_REGNUM, buf); |
| 584 | |
| 585 | /* DWARF2/GCC uses the stack address *before* the function call as a |
| 586 | frame's CFA. */ |
| 587 | return sp + 8; |
| 588 | } |
| 589 | |
| 590 | /* Convert a dwarf or dwarf2 regnumber to a GDB regnum. */ |
| 591 | |
| 592 | static int |
| 593 | m68k_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int num) |
| 594 | { |
| 595 | if (num < 8) |
| 596 | /* d0..7 */ |
| 597 | return (num - 0) + M68K_D0_REGNUM; |
| 598 | else if (num < 16) |
| 599 | /* a0..7 */ |
| 600 | return (num - 8) + M68K_A0_REGNUM; |
| 601 | else if (num < 24 && gdbarch_tdep (gdbarch)->fpregs_present) |
| 602 | /* fp0..7 */ |
| 603 | return (num - 16) + M68K_FP0_REGNUM; |
| 604 | else if (num == 25) |
| 605 | /* pc */ |
| 606 | return M68K_PC_REGNUM; |
| 607 | else |
| 608 | return -1; |
| 609 | } |
| 610 | |
| 611 | \f |
| 612 | struct m68k_frame_cache |
| 613 | { |
| 614 | /* Base address. */ |
| 615 | CORE_ADDR base; |
| 616 | CORE_ADDR sp_offset; |
| 617 | CORE_ADDR pc; |
| 618 | |
| 619 | /* Saved registers. */ |
| 620 | CORE_ADDR saved_regs[M68K_NUM_REGS]; |
| 621 | CORE_ADDR saved_sp; |
| 622 | |
| 623 | /* Stack space reserved for local variables. */ |
| 624 | long locals; |
| 625 | }; |
| 626 | |
| 627 | /* Allocate and initialize a frame cache. */ |
| 628 | |
| 629 | static struct m68k_frame_cache * |
| 630 | m68k_alloc_frame_cache (void) |
| 631 | { |
| 632 | struct m68k_frame_cache *cache; |
| 633 | int i; |
| 634 | |
| 635 | cache = FRAME_OBSTACK_ZALLOC (struct m68k_frame_cache); |
| 636 | |
| 637 | /* Base address. */ |
| 638 | cache->base = 0; |
| 639 | cache->sp_offset = -4; |
| 640 | cache->pc = 0; |
| 641 | |
| 642 | /* Saved registers. We initialize these to -1 since zero is a valid |
| 643 | offset (that's where %fp is supposed to be stored). */ |
| 644 | for (i = 0; i < M68K_NUM_REGS; i++) |
| 645 | cache->saved_regs[i] = -1; |
| 646 | |
| 647 | /* Frameless until proven otherwise. */ |
| 648 | cache->locals = -1; |
| 649 | |
| 650 | return cache; |
| 651 | } |
| 652 | |
| 653 | /* Check whether PC points at a code that sets up a new stack frame. |
| 654 | If so, it updates CACHE and returns the address of the first |
| 655 | instruction after the sequence that sets removes the "hidden" |
| 656 | argument from the stack or CURRENT_PC, whichever is smaller. |
| 657 | Otherwise, return PC. */ |
| 658 | |
| 659 | static CORE_ADDR |
| 660 | m68k_analyze_frame_setup (struct gdbarch *gdbarch, |
| 661 | CORE_ADDR pc, CORE_ADDR current_pc, |
| 662 | struct m68k_frame_cache *cache) |
| 663 | { |
| 664 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 665 | int op; |
| 666 | |
| 667 | if (pc >= current_pc) |
| 668 | return current_pc; |
| 669 | |
| 670 | op = read_memory_unsigned_integer (pc, 2, byte_order); |
| 671 | |
| 672 | if (op == P_LINKW_FP || op == P_LINKL_FP || op == P_PEA_FP) |
| 673 | { |
| 674 | cache->saved_regs[M68K_FP_REGNUM] = 0; |
| 675 | cache->sp_offset += 4; |
| 676 | if (op == P_LINKW_FP) |
| 677 | { |
| 678 | /* link.w %fp, #-N */ |
| 679 | /* link.w %fp, #0; adda.l #-N, %sp */ |
| 680 | cache->locals = -read_memory_integer (pc + 2, 2, byte_order); |
| 681 | |
| 682 | if (pc + 4 < current_pc && cache->locals == 0) |
| 683 | { |
| 684 | op = read_memory_unsigned_integer (pc + 4, 2, byte_order); |
| 685 | if (op == P_ADDAL_SP) |
| 686 | { |
| 687 | cache->locals = read_memory_integer (pc + 6, 4, byte_order); |
| 688 | return pc + 10; |
| 689 | } |
| 690 | } |
| 691 | |
| 692 | return pc + 4; |
| 693 | } |
| 694 | else if (op == P_LINKL_FP) |
| 695 | { |
| 696 | /* link.l %fp, #-N */ |
| 697 | cache->locals = -read_memory_integer (pc + 2, 4, byte_order); |
| 698 | return pc + 6; |
| 699 | } |
| 700 | else |
| 701 | { |
| 702 | /* pea (%fp); movea.l %sp, %fp */ |
| 703 | cache->locals = 0; |
| 704 | |
| 705 | if (pc + 2 < current_pc) |
| 706 | { |
| 707 | op = read_memory_unsigned_integer (pc + 2, 2, byte_order); |
| 708 | |
| 709 | if (op == P_MOVEAL_SP_FP) |
| 710 | { |
| 711 | /* move.l %sp, %fp */ |
| 712 | return pc + 4; |
| 713 | } |
| 714 | } |
| 715 | |
| 716 | return pc + 2; |
| 717 | } |
| 718 | } |
| 719 | else if ((op & 0170777) == P_SUBQW_SP || (op & 0170777) == P_SUBQL_SP) |
| 720 | { |
| 721 | /* subq.[wl] #N,%sp */ |
| 722 | /* subq.[wl] #8,%sp; subq.[wl] #N,%sp */ |
| 723 | cache->locals = (op & 07000) == 0 ? 8 : (op & 07000) >> 9; |
| 724 | if (pc + 2 < current_pc) |
| 725 | { |
| 726 | op = read_memory_unsigned_integer (pc + 2, 2, byte_order); |
| 727 | if ((op & 0170777) == P_SUBQW_SP || (op & 0170777) == P_SUBQL_SP) |
| 728 | { |
| 729 | cache->locals += (op & 07000) == 0 ? 8 : (op & 07000) >> 9; |
| 730 | return pc + 4; |
| 731 | } |
| 732 | } |
| 733 | return pc + 2; |
| 734 | } |
| 735 | else if (op == P_ADDAW_SP || op == P_LEA_SP_SP) |
| 736 | { |
| 737 | /* adda.w #-N,%sp */ |
| 738 | /* lea (-N,%sp),%sp */ |
| 739 | cache->locals = -read_memory_integer (pc + 2, 2, byte_order); |
| 740 | return pc + 4; |
| 741 | } |
| 742 | else if (op == P_ADDAL_SP) |
| 743 | { |
| 744 | /* adda.l #-N,%sp */ |
| 745 | cache->locals = -read_memory_integer (pc + 2, 4, byte_order); |
| 746 | return pc + 6; |
| 747 | } |
| 748 | |
| 749 | return pc; |
| 750 | } |
| 751 | |
| 752 | /* Check whether PC points at code that saves registers on the stack. |
| 753 | If so, it updates CACHE and returns the address of the first |
| 754 | instruction after the register saves or CURRENT_PC, whichever is |
| 755 | smaller. Otherwise, return PC. */ |
| 756 | |
| 757 | static CORE_ADDR |
| 758 | m68k_analyze_register_saves (struct gdbarch *gdbarch, CORE_ADDR pc, |
| 759 | CORE_ADDR current_pc, |
| 760 | struct m68k_frame_cache *cache) |
| 761 | { |
| 762 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 763 | |
| 764 | if (cache->locals >= 0) |
| 765 | { |
| 766 | CORE_ADDR offset; |
| 767 | int op; |
| 768 | int i, mask, regno; |
| 769 | |
| 770 | offset = -4 - cache->locals; |
| 771 | while (pc < current_pc) |
| 772 | { |
| 773 | op = read_memory_unsigned_integer (pc, 2, byte_order); |
| 774 | if (op == P_FMOVEMX_SP |
| 775 | && gdbarch_tdep (gdbarch)->fpregs_present) |
| 776 | { |
| 777 | /* fmovem.x REGS,-(%sp) */ |
| 778 | op = read_memory_unsigned_integer (pc + 2, 2, byte_order); |
| 779 | if ((op & 0xff00) == 0xe000) |
| 780 | { |
| 781 | mask = op & 0xff; |
| 782 | for (i = 0; i < 16; i++, mask >>= 1) |
| 783 | { |
| 784 | if (mask & 1) |
| 785 | { |
| 786 | cache->saved_regs[i + M68K_FP0_REGNUM] = offset; |
| 787 | offset -= 12; |
| 788 | } |
| 789 | } |
| 790 | pc += 4; |
| 791 | } |
| 792 | else |
| 793 | break; |
| 794 | } |
| 795 | else if ((op & 0177760) == P_MOVEL_SP) |
| 796 | { |
| 797 | /* move.l %R,-(%sp) */ |
| 798 | regno = op & 017; |
| 799 | cache->saved_regs[regno] = offset; |
| 800 | offset -= 4; |
| 801 | pc += 2; |
| 802 | } |
| 803 | else if (op == P_MOVEML_SP) |
| 804 | { |
| 805 | /* movem.l REGS,-(%sp) */ |
| 806 | mask = read_memory_unsigned_integer (pc + 2, 2, byte_order); |
| 807 | for (i = 0; i < 16; i++, mask >>= 1) |
| 808 | { |
| 809 | if (mask & 1) |
| 810 | { |
| 811 | cache->saved_regs[15 - i] = offset; |
| 812 | offset -= 4; |
| 813 | } |
| 814 | } |
| 815 | pc += 4; |
| 816 | } |
| 817 | else |
| 818 | break; |
| 819 | } |
| 820 | } |
| 821 | |
| 822 | return pc; |
| 823 | } |
| 824 | |
| 825 | |
| 826 | /* Do a full analysis of the prologue at PC and update CACHE |
| 827 | accordingly. Bail out early if CURRENT_PC is reached. Return the |
| 828 | address where the analysis stopped. |
| 829 | |
| 830 | We handle all cases that can be generated by gcc. |
| 831 | |
| 832 | For allocating a stack frame: |
| 833 | |
| 834 | link.w %a6,#-N |
| 835 | link.l %a6,#-N |
| 836 | pea (%fp); move.l %sp,%fp |
| 837 | link.w %a6,#0; add.l #-N,%sp |
| 838 | subq.l #N,%sp |
| 839 | subq.w #N,%sp |
| 840 | subq.w #8,%sp; subq.w #N-8,%sp |
| 841 | add.w #-N,%sp |
| 842 | lea (-N,%sp),%sp |
| 843 | add.l #-N,%sp |
| 844 | |
| 845 | For saving registers: |
| 846 | |
| 847 | fmovem.x REGS,-(%sp) |
| 848 | move.l R1,-(%sp) |
| 849 | move.l R1,-(%sp); move.l R2,-(%sp) |
| 850 | movem.l REGS,-(%sp) |
| 851 | |
| 852 | For setting up the PIC register: |
| 853 | |
| 854 | lea (%pc,N),%a5 |
| 855 | |
| 856 | */ |
| 857 | |
| 858 | static CORE_ADDR |
| 859 | m68k_analyze_prologue (struct gdbarch *gdbarch, CORE_ADDR pc, |
| 860 | CORE_ADDR current_pc, struct m68k_frame_cache *cache) |
| 861 | { |
| 862 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 863 | unsigned int op; |
| 864 | |
| 865 | pc = m68k_analyze_frame_setup (gdbarch, pc, current_pc, cache); |
| 866 | pc = m68k_analyze_register_saves (gdbarch, pc, current_pc, cache); |
| 867 | if (pc >= current_pc) |
| 868 | return current_pc; |
| 869 | |
| 870 | /* Check for GOT setup. */ |
| 871 | op = read_memory_unsigned_integer (pc, 4, byte_order); |
| 872 | if (op == P_LEA_PC_A5) |
| 873 | { |
| 874 | /* lea (%pc,N),%a5 */ |
| 875 | return pc + 8; |
| 876 | } |
| 877 | |
| 878 | return pc; |
| 879 | } |
| 880 | |
| 881 | /* Return PC of first real instruction. */ |
| 882 | |
| 883 | static CORE_ADDR |
| 884 | m68k_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR start_pc) |
| 885 | { |
| 886 | struct m68k_frame_cache cache; |
| 887 | CORE_ADDR pc; |
| 888 | |
| 889 | cache.locals = -1; |
| 890 | pc = m68k_analyze_prologue (gdbarch, start_pc, (CORE_ADDR) -1, &cache); |
| 891 | if (cache.locals < 0) |
| 892 | return start_pc; |
| 893 | return pc; |
| 894 | } |
| 895 | |
| 896 | static CORE_ADDR |
| 897 | m68k_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame) |
| 898 | { |
| 899 | gdb_byte buf[8]; |
| 900 | |
| 901 | frame_unwind_register (next_frame, gdbarch_pc_regnum (gdbarch), buf); |
| 902 | return extract_typed_address (buf, builtin_type (gdbarch)->builtin_func_ptr); |
| 903 | } |
| 904 | \f |
| 905 | /* Normal frames. */ |
| 906 | |
| 907 | static struct m68k_frame_cache * |
| 908 | m68k_frame_cache (struct frame_info *this_frame, void **this_cache) |
| 909 | { |
| 910 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 911 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 912 | struct m68k_frame_cache *cache; |
| 913 | gdb_byte buf[4]; |
| 914 | int i; |
| 915 | |
| 916 | if (*this_cache) |
| 917 | return (struct m68k_frame_cache *) *this_cache; |
| 918 | |
| 919 | cache = m68k_alloc_frame_cache (); |
| 920 | *this_cache = cache; |
| 921 | |
| 922 | /* In principle, for normal frames, %fp holds the frame pointer, |
| 923 | which holds the base address for the current stack frame. |
| 924 | However, for functions that don't need it, the frame pointer is |
| 925 | optional. For these "frameless" functions the frame pointer is |
| 926 | actually the frame pointer of the calling frame. Signal |
| 927 | trampolines are just a special case of a "frameless" function. |
| 928 | They (usually) share their frame pointer with the frame that was |
| 929 | in progress when the signal occurred. */ |
| 930 | |
| 931 | get_frame_register (this_frame, M68K_FP_REGNUM, buf); |
| 932 | cache->base = extract_unsigned_integer (buf, 4, byte_order); |
| 933 | if (cache->base == 0) |
| 934 | return cache; |
| 935 | |
| 936 | /* For normal frames, %pc is stored at 4(%fp). */ |
| 937 | cache->saved_regs[M68K_PC_REGNUM] = 4; |
| 938 | |
| 939 | cache->pc = get_frame_func (this_frame); |
| 940 | if (cache->pc != 0) |
| 941 | m68k_analyze_prologue (get_frame_arch (this_frame), cache->pc, |
| 942 | get_frame_pc (this_frame), cache); |
| 943 | |
| 944 | if (cache->locals < 0) |
| 945 | { |
| 946 | /* We didn't find a valid frame, which means that CACHE->base |
| 947 | currently holds the frame pointer for our calling frame. If |
| 948 | we're at the start of a function, or somewhere half-way its |
| 949 | prologue, the function's frame probably hasn't been fully |
| 950 | setup yet. Try to reconstruct the base address for the stack |
| 951 | frame by looking at the stack pointer. For truly "frameless" |
| 952 | functions this might work too. */ |
| 953 | |
| 954 | get_frame_register (this_frame, M68K_SP_REGNUM, buf); |
| 955 | cache->base = extract_unsigned_integer (buf, 4, byte_order) |
| 956 | + cache->sp_offset; |
| 957 | } |
| 958 | |
| 959 | /* Now that we have the base address for the stack frame we can |
| 960 | calculate the value of %sp in the calling frame. */ |
| 961 | cache->saved_sp = cache->base + 8; |
| 962 | |
| 963 | /* Adjust all the saved registers such that they contain addresses |
| 964 | instead of offsets. */ |
| 965 | for (i = 0; i < M68K_NUM_REGS; i++) |
| 966 | if (cache->saved_regs[i] != -1) |
| 967 | cache->saved_regs[i] += cache->base; |
| 968 | |
| 969 | return cache; |
| 970 | } |
| 971 | |
| 972 | static void |
| 973 | m68k_frame_this_id (struct frame_info *this_frame, void **this_cache, |
| 974 | struct frame_id *this_id) |
| 975 | { |
| 976 | struct m68k_frame_cache *cache = m68k_frame_cache (this_frame, this_cache); |
| 977 | |
| 978 | /* This marks the outermost frame. */ |
| 979 | if (cache->base == 0) |
| 980 | return; |
| 981 | |
| 982 | /* See the end of m68k_push_dummy_call. */ |
| 983 | *this_id = frame_id_build (cache->base + 8, cache->pc); |
| 984 | } |
| 985 | |
| 986 | static struct value * |
| 987 | m68k_frame_prev_register (struct frame_info *this_frame, void **this_cache, |
| 988 | int regnum) |
| 989 | { |
| 990 | struct m68k_frame_cache *cache = m68k_frame_cache (this_frame, this_cache); |
| 991 | |
| 992 | gdb_assert (regnum >= 0); |
| 993 | |
| 994 | if (regnum == M68K_SP_REGNUM && cache->saved_sp) |
| 995 | return frame_unwind_got_constant (this_frame, regnum, cache->saved_sp); |
| 996 | |
| 997 | if (regnum < M68K_NUM_REGS && cache->saved_regs[regnum] != -1) |
| 998 | return frame_unwind_got_memory (this_frame, regnum, |
| 999 | cache->saved_regs[regnum]); |
| 1000 | |
| 1001 | return frame_unwind_got_register (this_frame, regnum, regnum); |
| 1002 | } |
| 1003 | |
| 1004 | static const struct frame_unwind m68k_frame_unwind = |
| 1005 | { |
| 1006 | NORMAL_FRAME, |
| 1007 | default_frame_unwind_stop_reason, |
| 1008 | m68k_frame_this_id, |
| 1009 | m68k_frame_prev_register, |
| 1010 | NULL, |
| 1011 | default_frame_sniffer |
| 1012 | }; |
| 1013 | \f |
| 1014 | static CORE_ADDR |
| 1015 | m68k_frame_base_address (struct frame_info *this_frame, void **this_cache) |
| 1016 | { |
| 1017 | struct m68k_frame_cache *cache = m68k_frame_cache (this_frame, this_cache); |
| 1018 | |
| 1019 | return cache->base; |
| 1020 | } |
| 1021 | |
| 1022 | static const struct frame_base m68k_frame_base = |
| 1023 | { |
| 1024 | &m68k_frame_unwind, |
| 1025 | m68k_frame_base_address, |
| 1026 | m68k_frame_base_address, |
| 1027 | m68k_frame_base_address |
| 1028 | }; |
| 1029 | |
| 1030 | static struct frame_id |
| 1031 | m68k_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame) |
| 1032 | { |
| 1033 | CORE_ADDR fp; |
| 1034 | |
| 1035 | fp = get_frame_register_unsigned (this_frame, M68K_FP_REGNUM); |
| 1036 | |
| 1037 | /* See the end of m68k_push_dummy_call. */ |
| 1038 | return frame_id_build (fp + 8, get_frame_pc (this_frame)); |
| 1039 | } |
| 1040 | \f |
| 1041 | |
| 1042 | /* Figure out where the longjmp will land. Slurp the args out of the stack. |
| 1043 | We expect the first arg to be a pointer to the jmp_buf structure from which |
| 1044 | we extract the pc (JB_PC) that we will land at. The pc is copied into PC. |
| 1045 | This routine returns true on success. */ |
| 1046 | |
| 1047 | static int |
| 1048 | m68k_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc) |
| 1049 | { |
| 1050 | gdb_byte *buf; |
| 1051 | CORE_ADDR sp, jb_addr; |
| 1052 | struct gdbarch *gdbarch = get_frame_arch (frame); |
| 1053 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 1054 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 1055 | |
| 1056 | if (tdep->jb_pc < 0) |
| 1057 | { |
| 1058 | internal_error (__FILE__, __LINE__, |
| 1059 | _("m68k_get_longjmp_target: not implemented")); |
| 1060 | return 0; |
| 1061 | } |
| 1062 | |
| 1063 | buf = (gdb_byte *) alloca (gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT); |
| 1064 | sp = get_frame_register_unsigned (frame, gdbarch_sp_regnum (gdbarch)); |
| 1065 | |
| 1066 | if (target_read_memory (sp + SP_ARG0, /* Offset of first arg on stack. */ |
| 1067 | buf, gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT)) |
| 1068 | return 0; |
| 1069 | |
| 1070 | jb_addr = extract_unsigned_integer (buf, gdbarch_ptr_bit (gdbarch) |
| 1071 | / TARGET_CHAR_BIT, byte_order); |
| 1072 | |
| 1073 | if (target_read_memory (jb_addr + tdep->jb_pc * tdep->jb_elt_size, buf, |
| 1074 | gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT), |
| 1075 | byte_order) |
| 1076 | return 0; |
| 1077 | |
| 1078 | *pc = extract_unsigned_integer (buf, gdbarch_ptr_bit (gdbarch) |
| 1079 | / TARGET_CHAR_BIT, byte_order); |
| 1080 | return 1; |
| 1081 | } |
| 1082 | \f |
| 1083 | |
| 1084 | /* This is the implementation of gdbarch method |
| 1085 | return_in_first_hidden_param_p. */ |
| 1086 | |
| 1087 | static int |
| 1088 | m68k_return_in_first_hidden_param_p (struct gdbarch *gdbarch, |
| 1089 | struct type *type) |
| 1090 | { |
| 1091 | return 0; |
| 1092 | } |
| 1093 | |
| 1094 | /* System V Release 4 (SVR4). */ |
| 1095 | |
| 1096 | void |
| 1097 | m68k_svr4_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 1098 | { |
| 1099 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 1100 | |
| 1101 | /* SVR4 uses a different calling convention. */ |
| 1102 | set_gdbarch_return_value (gdbarch, m68k_svr4_return_value); |
| 1103 | |
| 1104 | /* SVR4 uses %a0 instead of %a1. */ |
| 1105 | tdep->struct_value_regnum = M68K_A0_REGNUM; |
| 1106 | |
| 1107 | /* SVR4 returns pointers in %a0. */ |
| 1108 | tdep->pointer_result_regnum = M68K_A0_REGNUM; |
| 1109 | } |
| 1110 | |
| 1111 | /* GCC's m68k "embedded" ABI. This is like the SVR4 ABI, but pointer |
| 1112 | values are returned in %d0, not %a0. */ |
| 1113 | |
| 1114 | static void |
| 1115 | m68k_embedded_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 1116 | { |
| 1117 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 1118 | |
| 1119 | m68k_svr4_init_abi (info, gdbarch); |
| 1120 | tdep->pointer_result_regnum = M68K_D0_REGNUM; |
| 1121 | } |
| 1122 | |
| 1123 | \f |
| 1124 | |
| 1125 | /* Function: m68k_gdbarch_init |
| 1126 | Initializer function for the m68k gdbarch vector. |
| 1127 | Called by gdbarch. Sets up the gdbarch vector(s) for this target. */ |
| 1128 | |
| 1129 | static struct gdbarch * |
| 1130 | m68k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) |
| 1131 | { |
| 1132 | struct gdbarch_tdep *tdep = NULL; |
| 1133 | struct gdbarch *gdbarch; |
| 1134 | struct gdbarch_list *best_arch; |
| 1135 | tdesc_arch_data_up tdesc_data; |
| 1136 | int i; |
| 1137 | enum m68k_flavour flavour = m68k_no_flavour; |
| 1138 | int has_fp = 1; |
| 1139 | const struct floatformat **long_double_format = floatformats_m68881_ext; |
| 1140 | |
| 1141 | /* Check any target description for validity. */ |
| 1142 | if (tdesc_has_registers (info.target_desc)) |
| 1143 | { |
| 1144 | const struct tdesc_feature *feature; |
| 1145 | int valid_p; |
| 1146 | |
| 1147 | feature = tdesc_find_feature (info.target_desc, |
| 1148 | "org.gnu.gdb.m68k.core"); |
| 1149 | |
| 1150 | if (feature == NULL) |
| 1151 | { |
| 1152 | feature = tdesc_find_feature (info.target_desc, |
| 1153 | "org.gnu.gdb.coldfire.core"); |
| 1154 | if (feature != NULL) |
| 1155 | flavour = m68k_coldfire_flavour; |
| 1156 | } |
| 1157 | |
| 1158 | if (feature == NULL) |
| 1159 | { |
| 1160 | feature = tdesc_find_feature (info.target_desc, |
| 1161 | "org.gnu.gdb.fido.core"); |
| 1162 | if (feature != NULL) |
| 1163 | flavour = m68k_fido_flavour; |
| 1164 | } |
| 1165 | |
| 1166 | if (feature == NULL) |
| 1167 | return NULL; |
| 1168 | |
| 1169 | tdesc_data = tdesc_data_alloc (); |
| 1170 | |
| 1171 | valid_p = 1; |
| 1172 | for (i = 0; i <= M68K_PC_REGNUM; i++) |
| 1173 | valid_p &= tdesc_numbered_register (feature, tdesc_data.get (), i, |
| 1174 | m68k_register_names[i]); |
| 1175 | |
| 1176 | if (!valid_p) |
| 1177 | return NULL; |
| 1178 | |
| 1179 | feature = tdesc_find_feature (info.target_desc, |
| 1180 | "org.gnu.gdb.coldfire.fp"); |
| 1181 | if (feature != NULL) |
| 1182 | { |
| 1183 | valid_p = 1; |
| 1184 | for (i = M68K_FP0_REGNUM; i <= M68K_FPI_REGNUM; i++) |
| 1185 | valid_p &= tdesc_numbered_register (feature, tdesc_data.get (), i, |
| 1186 | m68k_register_names[i]); |
| 1187 | if (!valid_p) |
| 1188 | return NULL; |
| 1189 | } |
| 1190 | else |
| 1191 | has_fp = 0; |
| 1192 | } |
| 1193 | |
| 1194 | /* The mechanism for returning floating values from function |
| 1195 | and the type of long double depend on whether we're |
| 1196 | on ColdFire or standard m68k. */ |
| 1197 | |
| 1198 | if (info.bfd_arch_info && info.bfd_arch_info->mach != 0) |
| 1199 | { |
| 1200 | const bfd_arch_info_type *coldfire_arch = |
| 1201 | bfd_lookup_arch (bfd_arch_m68k, bfd_mach_mcf_isa_a_nodiv); |
| 1202 | |
| 1203 | if (coldfire_arch |
| 1204 | && ((*info.bfd_arch_info->compatible) |
| 1205 | (info.bfd_arch_info, coldfire_arch))) |
| 1206 | flavour = m68k_coldfire_flavour; |
| 1207 | } |
| 1208 | |
| 1209 | /* Try to figure out if the arch uses floating registers to return |
| 1210 | floating point values from functions. On ColdFire, floating |
| 1211 | point values are returned in D0. */ |
| 1212 | int float_return = 0; |
| 1213 | if (has_fp && flavour != m68k_coldfire_flavour) |
| 1214 | float_return = 1; |
| 1215 | #ifdef HAVE_ELF |
| 1216 | if (info.abfd && bfd_get_flavour (info.abfd) == bfd_target_elf_flavour) |
| 1217 | { |
| 1218 | int fp_abi = bfd_elf_get_obj_attr_int (info.abfd, OBJ_ATTR_GNU, |
| 1219 | Tag_GNU_M68K_ABI_FP); |
| 1220 | if (fp_abi == 1) |
| 1221 | float_return = 1; |
| 1222 | else if (fp_abi == 2) |
| 1223 | float_return = 0; |
| 1224 | } |
| 1225 | #endif /* HAVE_ELF */ |
| 1226 | |
| 1227 | /* If there is already a candidate, use it. */ |
| 1228 | for (best_arch = gdbarch_list_lookup_by_info (arches, &info); |
| 1229 | best_arch != NULL; |
| 1230 | best_arch = gdbarch_list_lookup_by_info (best_arch->next, &info)) |
| 1231 | { |
| 1232 | if (flavour != gdbarch_tdep (best_arch->gdbarch)->flavour) |
| 1233 | continue; |
| 1234 | |
| 1235 | if (has_fp != gdbarch_tdep (best_arch->gdbarch)->fpregs_present) |
| 1236 | continue; |
| 1237 | |
| 1238 | if (float_return != gdbarch_tdep (best_arch->gdbarch)->float_return) |
| 1239 | continue; |
| 1240 | |
| 1241 | break; |
| 1242 | } |
| 1243 | |
| 1244 | if (best_arch != NULL) |
| 1245 | return best_arch->gdbarch; |
| 1246 | |
| 1247 | tdep = XCNEW (struct gdbarch_tdep); |
| 1248 | gdbarch = gdbarch_alloc (&info, tdep); |
| 1249 | tdep->fpregs_present = has_fp; |
| 1250 | tdep->float_return = float_return; |
| 1251 | tdep->flavour = flavour; |
| 1252 | |
| 1253 | if (flavour == m68k_coldfire_flavour || flavour == m68k_fido_flavour) |
| 1254 | long_double_format = floatformats_ieee_double; |
| 1255 | set_gdbarch_long_double_format (gdbarch, long_double_format); |
| 1256 | set_gdbarch_long_double_bit (gdbarch, long_double_format[0]->totalsize); |
| 1257 | |
| 1258 | set_gdbarch_skip_prologue (gdbarch, m68k_skip_prologue); |
| 1259 | set_gdbarch_breakpoint_kind_from_pc (gdbarch, m68k_breakpoint::kind_from_pc); |
| 1260 | set_gdbarch_sw_breakpoint_from_kind (gdbarch, m68k_breakpoint::bp_from_kind); |
| 1261 | |
| 1262 | /* Stack grows down. */ |
| 1263 | set_gdbarch_inner_than (gdbarch, core_addr_lessthan); |
| 1264 | set_gdbarch_frame_align (gdbarch, m68k_frame_align); |
| 1265 | |
| 1266 | set_gdbarch_believe_pcc_promotion (gdbarch, 1); |
| 1267 | if (flavour == m68k_coldfire_flavour || flavour == m68k_fido_flavour) |
| 1268 | set_gdbarch_decr_pc_after_break (gdbarch, 2); |
| 1269 | |
| 1270 | set_gdbarch_frame_args_skip (gdbarch, 8); |
| 1271 | set_gdbarch_dwarf2_reg_to_regnum (gdbarch, m68k_dwarf_reg_to_regnum); |
| 1272 | |
| 1273 | set_gdbarch_register_type (gdbarch, m68k_register_type); |
| 1274 | set_gdbarch_register_name (gdbarch, m68k_register_name); |
| 1275 | set_gdbarch_num_regs (gdbarch, M68K_NUM_REGS); |
| 1276 | set_gdbarch_sp_regnum (gdbarch, M68K_SP_REGNUM); |
| 1277 | set_gdbarch_pc_regnum (gdbarch, M68K_PC_REGNUM); |
| 1278 | set_gdbarch_ps_regnum (gdbarch, M68K_PS_REGNUM); |
| 1279 | set_gdbarch_convert_register_p (gdbarch, m68k_convert_register_p); |
| 1280 | set_gdbarch_register_to_value (gdbarch, m68k_register_to_value); |
| 1281 | set_gdbarch_value_to_register (gdbarch, m68k_value_to_register); |
| 1282 | |
| 1283 | if (has_fp) |
| 1284 | set_gdbarch_fp0_regnum (gdbarch, M68K_FP0_REGNUM); |
| 1285 | |
| 1286 | /* Function call & return. */ |
| 1287 | set_gdbarch_push_dummy_call (gdbarch, m68k_push_dummy_call); |
| 1288 | set_gdbarch_return_value (gdbarch, m68k_return_value); |
| 1289 | set_gdbarch_return_in_first_hidden_param_p (gdbarch, |
| 1290 | m68k_return_in_first_hidden_param_p); |
| 1291 | |
| 1292 | #if defined JB_PC && defined JB_ELEMENT_SIZE |
| 1293 | tdep->jb_pc = JB_PC; |
| 1294 | tdep->jb_elt_size = JB_ELEMENT_SIZE; |
| 1295 | #else |
| 1296 | tdep->jb_pc = -1; |
| 1297 | #endif |
| 1298 | tdep->pointer_result_regnum = M68K_D0_REGNUM; |
| 1299 | tdep->struct_value_regnum = M68K_A1_REGNUM; |
| 1300 | tdep->struct_return = reg_struct_return; |
| 1301 | |
| 1302 | /* Frame unwinder. */ |
| 1303 | set_gdbarch_dummy_id (gdbarch, m68k_dummy_id); |
| 1304 | set_gdbarch_unwind_pc (gdbarch, m68k_unwind_pc); |
| 1305 | |
| 1306 | /* Hook in the DWARF CFI frame unwinder. */ |
| 1307 | dwarf2_append_unwinders (gdbarch); |
| 1308 | |
| 1309 | frame_base_set_default (gdbarch, &m68k_frame_base); |
| 1310 | |
| 1311 | /* Hook in ABI-specific overrides, if they have been registered. */ |
| 1312 | gdbarch_init_osabi (info, gdbarch); |
| 1313 | |
| 1314 | /* Now we have tuned the configuration, set a few final things, |
| 1315 | based on what the OS ABI has told us. */ |
| 1316 | |
| 1317 | if (tdep->jb_pc >= 0) |
| 1318 | set_gdbarch_get_longjmp_target (gdbarch, m68k_get_longjmp_target); |
| 1319 | |
| 1320 | frame_unwind_append_unwinder (gdbarch, &m68k_frame_unwind); |
| 1321 | |
| 1322 | if (tdesc_data != nullptr) |
| 1323 | tdesc_use_registers (gdbarch, info.target_desc, std::move (tdesc_data)); |
| 1324 | |
| 1325 | return gdbarch; |
| 1326 | } |
| 1327 | |
| 1328 | |
| 1329 | static void |
| 1330 | m68k_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file) |
| 1331 | { |
| 1332 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 1333 | |
| 1334 | if (tdep == NULL) |
| 1335 | return; |
| 1336 | } |
| 1337 | |
| 1338 | /* OSABI sniffer for m68k. */ |
| 1339 | |
| 1340 | static enum gdb_osabi |
| 1341 | m68k_osabi_sniffer (bfd *abfd) |
| 1342 | { |
| 1343 | unsigned int elfosabi = elf_elfheader (abfd)->e_ident[EI_OSABI]; |
| 1344 | |
| 1345 | if (elfosabi == ELFOSABI_NONE) |
| 1346 | return GDB_OSABI_SVR4; |
| 1347 | |
| 1348 | return GDB_OSABI_UNKNOWN; |
| 1349 | } |
| 1350 | |
| 1351 | void _initialize_m68k_tdep (); |
| 1352 | void |
| 1353 | _initialize_m68k_tdep () |
| 1354 | { |
| 1355 | gdbarch_register (bfd_arch_m68k, m68k_gdbarch_init, m68k_dump_tdep); |
| 1356 | |
| 1357 | gdbarch_register_osabi_sniffer (bfd_arch_m68k, bfd_target_elf_flavour, |
| 1358 | m68k_osabi_sniffer); |
| 1359 | gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_SVR4, |
| 1360 | m68k_embedded_init_abi); |
| 1361 | } |