1 /* Target-dependent code for Lattice Mico32 processor, for GDB.
2 Contributed by Jon Beniston <jon@beniston.com>
4 Copyright (C) 2009-2018 Free Software Foundation, Inc.
6 This file is part of GDB.
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "frame-unwind.h"
24 #include "frame-base.h"
30 #include "gdb/sim-lm32.h"
31 #include "gdb/callback.h"
32 #include "gdb/remote-sim.h"
33 #include "sim-regno.h"
34 #include "arch-utils.h"
36 #include "trad-frame.h"
37 #include "reggroups.h"
38 #include "opcodes/lm32-desc.h"
41 /* Macros to extract fields from an instruction. */
42 #define LM32_OPCODE(insn) ((insn >> 26) & 0x3f)
43 #define LM32_REG0(insn) ((insn >> 21) & 0x1f)
44 #define LM32_REG1(insn) ((insn >> 16) & 0x1f)
45 #define LM32_REG2(insn) ((insn >> 11) & 0x1f)
46 #define LM32_IMM16(insn) ((((long)insn & 0xffff) << 16) >> 16)
50 /* gdbarch target dependent data here. Currently unused for LM32. */
53 struct lm32_frame_cache
55 /* The frame's base. Used when constructing a frame ID. */
60 /* Table indicating the location of each and every register. */
61 struct trad_frame_saved_reg *saved_regs;
64 /* Add the available register groups. */
67 lm32_add_reggroups (struct gdbarch *gdbarch)
69 reggroup_add (gdbarch, general_reggroup);
70 reggroup_add (gdbarch, all_reggroup);
71 reggroup_add (gdbarch, system_reggroup);
74 /* Return whether a given register is in a given group. */
77 lm32_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
78 struct reggroup *group)
80 if (group == general_reggroup)
81 return ((regnum >= SIM_LM32_R0_REGNUM) && (regnum <= SIM_LM32_RA_REGNUM))
82 || (regnum == SIM_LM32_PC_REGNUM);
83 else if (group == system_reggroup)
84 return ((regnum >= SIM_LM32_EA_REGNUM) && (regnum <= SIM_LM32_BA_REGNUM))
85 || ((regnum >= SIM_LM32_EID_REGNUM) && (regnum <= SIM_LM32_IP_REGNUM));
86 return default_register_reggroup_p (gdbarch, regnum, group);
89 /* Return a name that corresponds to the given register number. */
92 lm32_register_name (struct gdbarch *gdbarch, int reg_nr)
94 static const char *register_names[] = {
95 "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
96 "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
97 "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
98 "r24", "r25", "gp", "fp", "sp", "ra", "ea", "ba",
99 "PC", "EID", "EBA", "DEBA", "IE", "IM", "IP"
102 if ((reg_nr < 0) || (reg_nr >= ARRAY_SIZE (register_names)))
105 return register_names[reg_nr];
108 /* Return type of register. */
111 lm32_register_type (struct gdbarch *gdbarch, int reg_nr)
113 return builtin_type (gdbarch)->builtin_int32;
116 /* Return non-zero if a register can't be written. */
119 lm32_cannot_store_register (struct gdbarch *gdbarch, int regno)
121 return (regno == SIM_LM32_R0_REGNUM) || (regno == SIM_LM32_EID_REGNUM);
124 /* Analyze a function's prologue. */
127 lm32_analyze_prologue (struct gdbarch *gdbarch,
128 CORE_ADDR pc, CORE_ADDR limit,
129 struct lm32_frame_cache *info)
131 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
132 unsigned long instruction;
134 /* Keep reading though instructions, until we come across an instruction
135 that isn't likely to be part of the prologue. */
137 for (; pc < limit; pc += 4)
140 /* Read an instruction. */
141 instruction = read_memory_integer (pc, 4, byte_order);
143 if ((LM32_OPCODE (instruction) == OP_SW)
144 && (LM32_REG0 (instruction) == SIM_LM32_SP_REGNUM))
146 /* Any stack displaced store is likely part of the prologue.
147 Record that the register is being saved, and the offset
149 info->saved_regs[LM32_REG1 (instruction)].addr =
150 LM32_IMM16 (instruction);
152 else if ((LM32_OPCODE (instruction) == OP_ADDI)
153 && (LM32_REG1 (instruction) == SIM_LM32_SP_REGNUM))
155 /* An add to the SP is likely to be part of the prologue.
156 Adjust stack size by whatever the instruction adds to the sp. */
157 info->size -= LM32_IMM16 (instruction);
159 else if ( /* add fp,fp,sp */
160 ((LM32_OPCODE (instruction) == OP_ADD)
161 && (LM32_REG2 (instruction) == SIM_LM32_FP_REGNUM)
162 && (LM32_REG0 (instruction) == SIM_LM32_FP_REGNUM)
163 && (LM32_REG1 (instruction) == SIM_LM32_SP_REGNUM))
165 || ((LM32_OPCODE (instruction) == OP_ADDI)
166 && (LM32_REG1 (instruction) == SIM_LM32_FP_REGNUM)
167 && (LM32_REG0 (instruction) == SIM_LM32_R0_REGNUM)))
169 /* Likely to be in the prologue for functions that require
174 /* Any other instruction is likely not to be part of the
183 /* Return PC of first non prologue instruction, for the function at the
184 specified address. */
187 lm32_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
189 CORE_ADDR func_addr, limit_pc;
190 struct lm32_frame_cache frame_info;
191 struct trad_frame_saved_reg saved_regs[SIM_LM32_NUM_REGS];
193 /* See if we can determine the end of the prologue via the symbol table.
194 If so, then return either PC, or the PC after the prologue, whichever
196 if (find_pc_partial_function (pc, NULL, &func_addr, NULL))
198 CORE_ADDR post_prologue_pc
199 = skip_prologue_using_sal (gdbarch, func_addr);
200 if (post_prologue_pc != 0)
201 return std::max (pc, post_prologue_pc);
204 /* Can't determine prologue from the symbol table, need to examine
207 /* Find an upper limit on the function prologue using the debug
208 information. If the debug information could not be used to provide
209 that bound, then use an arbitrary large number as the upper bound. */
210 limit_pc = skip_prologue_using_sal (gdbarch, pc);
212 limit_pc = pc + 100; /* Magic. */
214 frame_info.saved_regs = saved_regs;
215 return lm32_analyze_prologue (gdbarch, pc, limit_pc, &frame_info);
218 /* Create a breakpoint instruction. */
219 constexpr gdb_byte lm32_break_insn[4] = { OP_RAISE << 2, 0, 0, 2 };
221 typedef BP_MANIPULATION (lm32_break_insn) lm32_breakpoint;
224 /* Setup registers and stack for faking a call to a function in the
228 lm32_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
229 struct regcache *regcache, CORE_ADDR bp_addr,
230 int nargs, struct value **args, CORE_ADDR sp,
231 int struct_return, CORE_ADDR struct_addr)
233 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
234 int first_arg_reg = SIM_LM32_R1_REGNUM;
235 int num_arg_regs = 8;
238 /* Set the return address. */
239 regcache_cooked_write_signed (regcache, SIM_LM32_RA_REGNUM, bp_addr);
241 /* If we're returning a large struct, a pointer to the address to
242 store it at is passed as a first hidden parameter. */
245 regcache_cooked_write_unsigned (regcache, first_arg_reg, struct_addr);
251 /* Setup parameters. */
252 for (i = 0; i < nargs; i++)
254 struct value *arg = args[i];
255 struct type *arg_type = check_typedef (value_type (arg));
259 /* Promote small integer types to int. */
260 switch (TYPE_CODE (arg_type))
265 case TYPE_CODE_RANGE:
267 if (TYPE_LENGTH (arg_type) < 4)
269 arg_type = builtin_type (gdbarch)->builtin_int32;
270 arg = value_cast (arg_type, arg);
275 /* FIXME: Handle structures. */
277 contents = (gdb_byte *) value_contents (arg);
278 val = extract_unsigned_integer (contents, TYPE_LENGTH (arg_type),
281 /* First num_arg_regs parameters are passed by registers,
282 and the rest are passed on the stack. */
283 if (i < num_arg_regs)
284 regcache_cooked_write_unsigned (regcache, first_arg_reg + i, val);
287 write_memory_unsigned_integer (sp, TYPE_LENGTH (arg_type), byte_order,
293 /* Update stack pointer. */
294 regcache_cooked_write_signed (regcache, SIM_LM32_SP_REGNUM, sp);
296 /* Return adjusted stack pointer. */
300 /* Extract return value after calling a function in the inferior. */
303 lm32_extract_return_value (struct type *type, struct regcache *regcache,
306 struct gdbarch *gdbarch = regcache->arch ();
307 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
309 CORE_ADDR return_buffer;
311 if (TYPE_CODE (type) != TYPE_CODE_STRUCT
312 && TYPE_CODE (type) != TYPE_CODE_UNION
313 && TYPE_CODE (type) != TYPE_CODE_ARRAY && TYPE_LENGTH (type) <= 4)
315 /* Return value is returned in a single register. */
316 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
317 store_unsigned_integer (valbuf, TYPE_LENGTH (type), byte_order, l);
319 else if ((TYPE_CODE (type) == TYPE_CODE_INT) && (TYPE_LENGTH (type) == 8))
321 /* 64-bit values are returned in a register pair. */
322 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
323 memcpy (valbuf, &l, 4);
324 regcache_cooked_read_unsigned (regcache, SIM_LM32_R2_REGNUM, &l);
325 memcpy (valbuf + 4, &l, 4);
329 /* Aggregate types greater than a single register are returned
330 in memory. FIXME: Unless they are only 2 regs?. */
331 regcache_cooked_read_unsigned (regcache, SIM_LM32_R1_REGNUM, &l);
333 read_memory (return_buffer, valbuf, TYPE_LENGTH (type));
337 /* Write into appropriate registers a function return value of type
338 TYPE, given in virtual format. */
340 lm32_store_return_value (struct type *type, struct regcache *regcache,
341 const gdb_byte *valbuf)
343 struct gdbarch *gdbarch = regcache->arch ();
344 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
346 int len = TYPE_LENGTH (type);
350 val = extract_unsigned_integer (valbuf, len, byte_order);
351 regcache_cooked_write_unsigned (regcache, SIM_LM32_R1_REGNUM, val);
355 val = extract_unsigned_integer (valbuf, 4, byte_order);
356 regcache_cooked_write_unsigned (regcache, SIM_LM32_R1_REGNUM, val);
357 val = extract_unsigned_integer (valbuf + 4, len - 4, byte_order);
358 regcache_cooked_write_unsigned (regcache, SIM_LM32_R2_REGNUM, val);
361 error (_("lm32_store_return_value: type length too large."));
364 /* Determine whether a functions return value is in a register or memory. */
365 static enum return_value_convention
366 lm32_return_value (struct gdbarch *gdbarch, struct value *function,
367 struct type *valtype, struct regcache *regcache,
368 gdb_byte *readbuf, const gdb_byte *writebuf)
370 enum type_code code = TYPE_CODE (valtype);
372 if (code == TYPE_CODE_STRUCT
373 || code == TYPE_CODE_UNION
374 || code == TYPE_CODE_ARRAY || TYPE_LENGTH (valtype) > 8)
375 return RETURN_VALUE_STRUCT_CONVENTION;
378 lm32_extract_return_value (valtype, regcache, readbuf);
380 lm32_store_return_value (valtype, regcache, writebuf);
382 return RETURN_VALUE_REGISTER_CONVENTION;
386 lm32_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
388 return frame_unwind_register_unsigned (next_frame, SIM_LM32_PC_REGNUM);
392 lm32_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame)
394 return frame_unwind_register_unsigned (next_frame, SIM_LM32_SP_REGNUM);
397 static struct frame_id
398 lm32_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)
400 CORE_ADDR sp = get_frame_register_unsigned (this_frame, SIM_LM32_SP_REGNUM);
402 return frame_id_build (sp, get_frame_pc (this_frame));
405 /* Put here the code to store, into fi->saved_regs, the addresses of
406 the saved registers of frame described by FRAME_INFO. This
407 includes special registers such as pc and fp saved in special ways
408 in the stack frame. sp is even more special: the address we return
409 for it IS the sp for the next frame. */
411 static struct lm32_frame_cache *
412 lm32_frame_cache (struct frame_info *this_frame, void **this_prologue_cache)
414 CORE_ADDR current_pc;
417 struct lm32_frame_cache *info;
420 if ((*this_prologue_cache))
421 return (struct lm32_frame_cache *) (*this_prologue_cache);
423 info = FRAME_OBSTACK_ZALLOC (struct lm32_frame_cache);
424 (*this_prologue_cache) = info;
425 info->saved_regs = trad_frame_alloc_saved_regs (this_frame);
427 info->pc = get_frame_func (this_frame);
428 current_pc = get_frame_pc (this_frame);
429 lm32_analyze_prologue (get_frame_arch (this_frame),
430 info->pc, current_pc, info);
432 /* Compute the frame's base, and the previous frame's SP. */
433 this_base = get_frame_register_unsigned (this_frame, SIM_LM32_SP_REGNUM);
434 prev_sp = this_base + info->size;
435 info->base = this_base;
437 /* Convert callee save offsets into addresses. */
438 for (i = 0; i < gdbarch_num_regs (get_frame_arch (this_frame)) - 1; i++)
440 if (trad_frame_addr_p (info->saved_regs, i))
441 info->saved_regs[i].addr = this_base + info->saved_regs[i].addr;
444 /* The call instruction moves the caller's PC in the callee's RA register.
445 Since this is an unwind, do the reverse. Copy the location of RA register
446 into PC (the address / regnum) so that a request for PC will be
447 converted into a request for the RA register. */
448 info->saved_regs[SIM_LM32_PC_REGNUM] = info->saved_regs[SIM_LM32_RA_REGNUM];
450 /* The previous frame's SP needed to be computed. Save the computed
452 trad_frame_set_value (info->saved_regs, SIM_LM32_SP_REGNUM, prev_sp);
458 lm32_frame_this_id (struct frame_info *this_frame, void **this_cache,
459 struct frame_id *this_id)
461 struct lm32_frame_cache *cache = lm32_frame_cache (this_frame, this_cache);
463 /* This marks the outermost frame. */
464 if (cache->base == 0)
467 (*this_id) = frame_id_build (cache->base, cache->pc);
470 static struct value *
471 lm32_frame_prev_register (struct frame_info *this_frame,
472 void **this_prologue_cache, int regnum)
474 struct lm32_frame_cache *info;
476 info = lm32_frame_cache (this_frame, this_prologue_cache);
477 return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
480 static const struct frame_unwind lm32_frame_unwind = {
482 default_frame_unwind_stop_reason,
484 lm32_frame_prev_register,
486 default_frame_sniffer
490 lm32_frame_base_address (struct frame_info *this_frame, void **this_cache)
492 struct lm32_frame_cache *info = lm32_frame_cache (this_frame, this_cache);
497 static const struct frame_base lm32_frame_base = {
499 lm32_frame_base_address,
500 lm32_frame_base_address,
501 lm32_frame_base_address
505 lm32_frame_align (struct gdbarch *gdbarch, CORE_ADDR sp)
507 /* Align to the size of an instruction (so that they can safely be
508 pushed onto the stack. */
512 static struct gdbarch *
513 lm32_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
515 struct gdbarch *gdbarch;
516 struct gdbarch_tdep *tdep;
518 /* If there is already a candidate, use it. */
519 arches = gdbarch_list_lookup_by_info (arches, &info);
521 return arches->gdbarch;
523 /* None found, create a new architecture from the information provided. */
524 tdep = XCNEW (struct gdbarch_tdep);
525 gdbarch = gdbarch_alloc (&info, tdep);
528 set_gdbarch_short_bit (gdbarch, 16);
529 set_gdbarch_int_bit (gdbarch, 32);
530 set_gdbarch_long_bit (gdbarch, 32);
531 set_gdbarch_long_long_bit (gdbarch, 64);
532 set_gdbarch_float_bit (gdbarch, 32);
533 set_gdbarch_double_bit (gdbarch, 64);
534 set_gdbarch_long_double_bit (gdbarch, 64);
535 set_gdbarch_ptr_bit (gdbarch, 32);
538 set_gdbarch_num_regs (gdbarch, SIM_LM32_NUM_REGS);
539 set_gdbarch_sp_regnum (gdbarch, SIM_LM32_SP_REGNUM);
540 set_gdbarch_pc_regnum (gdbarch, SIM_LM32_PC_REGNUM);
541 set_gdbarch_register_name (gdbarch, lm32_register_name);
542 set_gdbarch_register_type (gdbarch, lm32_register_type);
543 set_gdbarch_cannot_store_register (gdbarch, lm32_cannot_store_register);
546 set_gdbarch_skip_prologue (gdbarch, lm32_skip_prologue);
547 set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
548 set_gdbarch_decr_pc_after_break (gdbarch, 0);
549 set_gdbarch_frame_args_skip (gdbarch, 0);
551 /* Frame unwinding. */
552 set_gdbarch_frame_align (gdbarch, lm32_frame_align);
553 frame_base_set_default (gdbarch, &lm32_frame_base);
554 set_gdbarch_unwind_pc (gdbarch, lm32_unwind_pc);
555 set_gdbarch_unwind_sp (gdbarch, lm32_unwind_sp);
556 set_gdbarch_dummy_id (gdbarch, lm32_dummy_id);
557 frame_unwind_append_unwinder (gdbarch, &lm32_frame_unwind);
560 set_gdbarch_breakpoint_kind_from_pc (gdbarch, lm32_breakpoint::kind_from_pc);
561 set_gdbarch_sw_breakpoint_from_kind (gdbarch, lm32_breakpoint::bp_from_kind);
562 set_gdbarch_have_nonsteppable_watchpoint (gdbarch, 1);
564 /* Calling functions in the inferior. */
565 set_gdbarch_push_dummy_call (gdbarch, lm32_push_dummy_call);
566 set_gdbarch_return_value (gdbarch, lm32_return_value);
568 lm32_add_reggroups (gdbarch);
569 set_gdbarch_register_reggroup_p (gdbarch, lm32_register_reggroup_p);
575 _initialize_lm32_tdep (void)
577 register_gdbarch_init (bfd_arch_lm32, lm32_gdbarch_init);