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m68hc11-tdep.c
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m68hc11-tdep.c
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/* Target-dependent code for Motorola 68HC11 & 68HC12
Copyright (C) 1999-2024 Free Software Foundation, Inc.
Contributed by Stephane Carrez, stcarrez@nerim.fr
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "frame.h"
#include "frame-unwind.h"
#include "frame-base.h"
#include "dwarf2/frame.h"
#include "trad-frame.h"
#include "symtab.h"
#include "gdbtypes.h"
#include "gdbcmd.h"
#include "gdbcore.h"
#include "value.h"
#include "inferior.h"
#include "dis-asm.h"
#include "symfile.h"
#include "objfiles.h"
#include "arch-utils.h"
#include "regcache.h"
#include "reggroups.h"
#include "gdbarch.h"
#include "target.h"
#include "opcode/m68hc11.h"
#include "elf/m68hc11.h"
#include "elf-bfd.h"
/* Macros for setting and testing a bit in a minimal symbol.
For 68HC11/68HC12 we have two flags that tell which return
type the function is using. This is used for prologue and frame
analysis to compute correct stack frame layout.
The MSB of the minimal symbol's "info" field is used for this purpose.
MSYMBOL_SET_RTC Actually sets the "RTC" bit.
MSYMBOL_SET_RTI Actually sets the "RTI" bit.
MSYMBOL_IS_RTC Tests the "RTC" bit in a minimal symbol.
MSYMBOL_IS_RTI Tests the "RTC" bit in a minimal symbol. */
#define MSYMBOL_SET_RTC(msym) \
(msym)->set_target_flag_1 (true)
#define MSYMBOL_SET_RTI(msym) \
(msym)->set_target_flag_2 (true)
#define MSYMBOL_IS_RTC(msym) \
(msym)->target_flag_1 ()
#define MSYMBOL_IS_RTI(msym) \
(msym)->target_flag_2 ()
enum insn_return_kind {
RETURN_RTS,
RETURN_RTC,
RETURN_RTI
};
/* Register numbers of various important registers. */
#define HARD_X_REGNUM 0
#define HARD_D_REGNUM 1
#define HARD_Y_REGNUM 2
#define HARD_SP_REGNUM 3
#define HARD_PC_REGNUM 4
#define HARD_A_REGNUM 5
#define HARD_B_REGNUM 6
#define HARD_CCR_REGNUM 7
/* 68HC12 page number register.
Note: to keep a compatibility with gcc register naming, we must
not have to rename FP and other soft registers. The page register
is a real hard register and must therefore be counted by gdbarch_num_regs.
For this it has the same number as Z register (which is not used). */
#define HARD_PAGE_REGNUM 8
#define M68HC11_LAST_HARD_REG (HARD_PAGE_REGNUM)
/* Z is replaced by X or Y by gcc during machine reorg.
??? There is no way to get it and even know whether
it's in X or Y or in ZS. */
#define SOFT_Z_REGNUM 8
/* Soft registers. These registers are special. There are treated
like normal hard registers by gcc and gdb (ie, within dwarf2 info).
They are physically located in memory. */
#define SOFT_FP_REGNUM 9
#define SOFT_TMP_REGNUM 10
#define SOFT_ZS_REGNUM 11
#define SOFT_XY_REGNUM 12
#define SOFT_UNUSED_REGNUM 13
#define SOFT_D1_REGNUM 14
#define SOFT_D32_REGNUM (SOFT_D1_REGNUM+31)
#define M68HC11_MAX_SOFT_REGS 32
#define M68HC11_NUM_REGS (M68HC11_LAST_HARD_REG + 1)
#define M68HC11_NUM_PSEUDO_REGS (M68HC11_MAX_SOFT_REGS+5)
#define M68HC11_ALL_REGS (M68HC11_NUM_REGS+M68HC11_NUM_PSEUDO_REGS)
#define M68HC11_REG_SIZE (2)
#define M68HC12_NUM_REGS (9)
#define M68HC12_NUM_PSEUDO_REGS ((M68HC11_MAX_SOFT_REGS+5)+1-1)
#define M68HC12_HARD_PC_REGNUM (SOFT_D32_REGNUM+1)
struct insn_sequence;
struct m68gc11_gdbarch_tdep : gdbarch_tdep_base
{
/* Stack pointer correction value. For 68hc11, the stack pointer points
to the next push location. An offset of 1 must be applied to obtain
the address where the last value is saved. For 68hc12, the stack
pointer points to the last value pushed. No offset is necessary. */
int stack_correction = 0;
/* Description of instructions in the prologue. */
struct insn_sequence *prologue = nullptr;
/* True if the page memory bank register is available
and must be used. */
int use_page_register = 0;
/* ELF flags for ABI. */
int elf_flags = 0;
};
static int
stack_correction (gdbarch *arch)
{
m68gc11_gdbarch_tdep *tdep = gdbarch_tdep<m68gc11_gdbarch_tdep> (arch);
return tdep->stack_correction;
}
static int
use_page_register (gdbarch *arch)
{
m68gc11_gdbarch_tdep *tdep = gdbarch_tdep<m68gc11_gdbarch_tdep> (arch);
return tdep->stack_correction;
}
struct m68hc11_unwind_cache
{
/* The previous frame's inner most stack address. Used as this
frame ID's stack_addr. */
CORE_ADDR prev_sp;
/* The frame's base, optionally used by the high-level debug info. */
CORE_ADDR base;
CORE_ADDR pc;
int size;
int prologue_type;
CORE_ADDR return_pc;
CORE_ADDR sp_offset;
int frameless;
enum insn_return_kind return_kind;
/* Table indicating the location of each and every register. */
trad_frame_saved_reg *saved_regs;
};
/* Table of registers for 68HC11. This includes the hard registers
and the soft registers used by GCC. */
static const char *
m68hc11_register_names[] =
{
"x", "d", "y", "sp", "pc", "a", "b",
"ccr", "page", "frame","tmp", "zs", "xy", 0,
"d1", "d2", "d3", "d4", "d5", "d6", "d7",
"d8", "d9", "d10", "d11", "d12", "d13", "d14",
"d15", "d16", "d17", "d18", "d19", "d20", "d21",
"d22", "d23", "d24", "d25", "d26", "d27", "d28",
"d29", "d30", "d31", "d32"
};
struct m68hc11_soft_reg
{
const char *name;
CORE_ADDR addr;
};
static struct m68hc11_soft_reg soft_regs[M68HC11_ALL_REGS];
#define M68HC11_FP_ADDR soft_regs[SOFT_FP_REGNUM].addr
static int soft_min_addr;
static int soft_max_addr;
static int soft_reg_initialized = 0;
/* Look in the symbol table for the address of a pseudo register
in memory. If we don't find it, pretend the register is not used
and not available. */
static void
m68hc11_get_register_info (struct m68hc11_soft_reg *reg, const char *name)
{
struct bound_minimal_symbol msymbol;
msymbol = lookup_minimal_symbol (name, NULL, NULL);
if (msymbol.minsym)
{
reg->addr = msymbol.value_address ();
reg->name = xstrdup (name);
/* Keep track of the address range for soft registers. */
if (reg->addr < (CORE_ADDR) soft_min_addr)
soft_min_addr = reg->addr;
if (reg->addr > (CORE_ADDR) soft_max_addr)
soft_max_addr = reg->addr;
}
else
{
reg->name = 0;
reg->addr = 0;
}
}
/* Initialize the table of soft register addresses according
to the symbol table. */
static void
m68hc11_initialize_register_info (void)
{
int i;
if (soft_reg_initialized)
return;
soft_min_addr = INT_MAX;
soft_max_addr = 0;
for (i = 0; i < M68HC11_ALL_REGS; i++)
{
soft_regs[i].name = 0;
}
m68hc11_get_register_info (&soft_regs[SOFT_FP_REGNUM], "_.frame");
m68hc11_get_register_info (&soft_regs[SOFT_TMP_REGNUM], "_.tmp");
m68hc11_get_register_info (&soft_regs[SOFT_ZS_REGNUM], "_.z");
soft_regs[SOFT_Z_REGNUM] = soft_regs[SOFT_ZS_REGNUM];
m68hc11_get_register_info (&soft_regs[SOFT_XY_REGNUM], "_.xy");
for (i = SOFT_D1_REGNUM; i < M68HC11_MAX_SOFT_REGS; i++)
{
char buf[10];
xsnprintf (buf, sizeof (buf), "_.d%d", i - SOFT_D1_REGNUM + 1);
m68hc11_get_register_info (&soft_regs[i], buf);
}
if (soft_regs[SOFT_FP_REGNUM].name == 0)
warning (_("No frame soft register found in the symbol table.\n"
"Stack backtrace will not work."));
soft_reg_initialized = 1;
}
/* Given an address in memory, return the soft register number if
that address corresponds to a soft register. Returns -1 if not. */
static int
m68hc11_which_soft_register (CORE_ADDR addr)
{
int i;
if (addr < soft_min_addr || addr > soft_max_addr)
return -1;
for (i = SOFT_FP_REGNUM; i < M68HC11_ALL_REGS; i++)
{
if (soft_regs[i].name && soft_regs[i].addr == addr)
return i;
}
return -1;
}
/* Fetch a pseudo register. The 68hc11 soft registers are treated like
pseudo registers. They are located in memory. Translate the register
fetch into a memory read. */
static enum register_status
m68hc11_pseudo_register_read (struct gdbarch *gdbarch,
readable_regcache *regcache,
int regno, gdb_byte *buf)
{
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
/* The PC is a pseudo reg only for 68HC12 with the memory bank
addressing mode. */
if (regno == M68HC12_HARD_PC_REGNUM)
{
ULONGEST pc;
const int regsize = 4;
enum register_status status;
status = regcache->cooked_read (HARD_PC_REGNUM, &pc);
if (status != REG_VALID)
return status;
if (pc >= 0x8000 && pc < 0xc000)
{
ULONGEST page;
regcache->cooked_read (HARD_PAGE_REGNUM, &page);
pc -= 0x8000;
pc += (page << 14);
pc += 0x1000000;
}
store_unsigned_integer (buf, regsize, byte_order, pc);
return REG_VALID;
}
m68hc11_initialize_register_info ();
/* Fetch a soft register: translate into a memory read. */
if (soft_regs[regno].name)
{
target_read_memory (soft_regs[regno].addr, buf, 2);
}
else
{
memset (buf, 0, 2);
}
return REG_VALID;
}
/* Store a pseudo register. Translate the register store
into a memory write. */
static void
m68hc11_pseudo_register_write (struct gdbarch *gdbarch,
struct regcache *regcache,
int regno, const gdb_byte *buf)
{
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
/* The PC is a pseudo reg only for 68HC12 with the memory bank
addressing mode. */
if (regno == M68HC12_HARD_PC_REGNUM)
{
const int regsize = 4;
gdb_byte *tmp = (gdb_byte *) alloca (regsize);
CORE_ADDR pc;
memcpy (tmp, buf, regsize);
pc = extract_unsigned_integer (tmp, regsize, byte_order);
if (pc >= 0x1000000)
{
pc -= 0x1000000;
regcache_cooked_write_unsigned (regcache, HARD_PAGE_REGNUM,
(pc >> 14) & 0x0ff);
pc &= 0x03fff;
regcache_cooked_write_unsigned (regcache, HARD_PC_REGNUM,
pc + 0x8000);
}
else
regcache_cooked_write_unsigned (regcache, HARD_PC_REGNUM, pc);
return;
}
m68hc11_initialize_register_info ();
/* Store a soft register: translate into a memory write. */
if (soft_regs[regno].name)
{
const int regsize = 2;
gdb_byte *tmp = (gdb_byte *) alloca (regsize);
memcpy (tmp, buf, regsize);
target_write_memory (soft_regs[regno].addr, tmp, regsize);
}
}
static const char *
m68hc11_register_name (struct gdbarch *gdbarch, int reg_nr)
{
if (reg_nr == M68HC12_HARD_PC_REGNUM && use_page_register (gdbarch))
return "pc";
if (reg_nr == HARD_PC_REGNUM && use_page_register (gdbarch))
return "ppc";
if (reg_nr >= M68HC11_ALL_REGS)
return "";
m68hc11_initialize_register_info ();
/* If we don't know the address of a soft register, pretend it
does not exist. */
if (reg_nr > M68HC11_LAST_HARD_REG && soft_regs[reg_nr].name == 0)
return "";
return m68hc11_register_names[reg_nr];
}
constexpr gdb_byte m68hc11_break_insn[] = {0x0};
typedef BP_MANIPULATION (m68hc11_break_insn) m68hc11_breakpoint;
/* 68HC11 & 68HC12 prologue analysis. */
#define MAX_CODES 12
/* 68HC11 opcodes. */
#undef M6811_OP_PAGE2
#define M6811_OP_PAGE2 (0x18)
#define M6811_OP_LDX (0xde)
#define M6811_OP_LDX_EXT (0xfe)
#define M6811_OP_PSHX (0x3c)
#define M6811_OP_STS (0x9f)
#define M6811_OP_STS_EXT (0xbf)
#define M6811_OP_TSX (0x30)
#define M6811_OP_XGDX (0x8f)
#define M6811_OP_ADDD (0xc3)
#define M6811_OP_TXS (0x35)
#define M6811_OP_DES (0x34)
/* 68HC12 opcodes. */
#define M6812_OP_PAGE2 (0x18)
#define M6812_OP_MOVW (0x01)
#define M6812_PB_PSHW (0xae)
#define M6812_OP_STS (0x5f)
#define M6812_OP_STS_EXT (0x7f)
#define M6812_OP_LEAS (0x1b)
#define M6812_OP_PSHX (0x34)
#define M6812_OP_PSHY (0x35)
/* Operand extraction. */
#define OP_DIRECT (0x100) /* 8-byte direct addressing. */
#define OP_IMM_LOW (0x200) /* Low part of 16-bit constant/address. */
#define OP_IMM_HIGH (0x300) /* High part of 16-bit constant/address. */
#define OP_PBYTE (0x400) /* 68HC12 indexed operand. */
/* Identification of the sequence. */
enum m6811_seq_type
{
P_LAST = 0,
P_SAVE_REG, /* Save a register on the stack. */
P_SET_FRAME, /* Setup the frame pointer. */
P_LOCAL_1, /* Allocate 1 byte for locals. */
P_LOCAL_2, /* Allocate 2 bytes for locals. */
P_LOCAL_N /* Allocate N bytes for locals. */
};
struct insn_sequence {
enum m6811_seq_type type;
unsigned length;
unsigned short code[MAX_CODES];
};
/* Sequence of instructions in the 68HC11 function prologue. */
static struct insn_sequence m6811_prologue[] = {
/* Sequences to save a soft-register. */
{ P_SAVE_REG, 3, { M6811_OP_LDX, OP_DIRECT,
M6811_OP_PSHX } },
{ P_SAVE_REG, 5, { M6811_OP_PAGE2, M6811_OP_LDX, OP_DIRECT,
M6811_OP_PAGE2, M6811_OP_PSHX } },
{ P_SAVE_REG, 4, { M6811_OP_LDX_EXT, OP_IMM_HIGH, OP_IMM_LOW,
M6811_OP_PSHX } },
{ P_SAVE_REG, 6, { M6811_OP_PAGE2, M6811_OP_LDX_EXT, OP_IMM_HIGH, OP_IMM_LOW,
M6811_OP_PAGE2, M6811_OP_PSHX } },
/* Sequences to allocate local variables. */
{ P_LOCAL_N, 7, { M6811_OP_TSX,
M6811_OP_XGDX,
M6811_OP_ADDD, OP_IMM_HIGH, OP_IMM_LOW,
M6811_OP_XGDX,
M6811_OP_TXS } },
{ P_LOCAL_N, 11, { M6811_OP_PAGE2, M6811_OP_TSX,
M6811_OP_PAGE2, M6811_OP_XGDX,
M6811_OP_ADDD, OP_IMM_HIGH, OP_IMM_LOW,
M6811_OP_PAGE2, M6811_OP_XGDX,
M6811_OP_PAGE2, M6811_OP_TXS } },
{ P_LOCAL_1, 1, { M6811_OP_DES } },
{ P_LOCAL_2, 1, { M6811_OP_PSHX } },
{ P_LOCAL_2, 2, { M6811_OP_PAGE2, M6811_OP_PSHX } },
/* Initialize the frame pointer. */
{ P_SET_FRAME, 2, { M6811_OP_STS, OP_DIRECT } },
{ P_SET_FRAME, 3, { M6811_OP_STS_EXT, OP_IMM_HIGH, OP_IMM_LOW } },
{ P_LAST, 0, { 0 } }
};
/* Sequence of instructions in the 68HC12 function prologue. */
static struct insn_sequence m6812_prologue[] = {
{ P_SAVE_REG, 5, { M6812_OP_PAGE2, M6812_OP_MOVW, M6812_PB_PSHW,
OP_IMM_HIGH, OP_IMM_LOW } },
{ P_SET_FRAME, 2, { M6812_OP_STS, OP_DIRECT } },
{ P_SET_FRAME, 3, { M6812_OP_STS_EXT, OP_IMM_HIGH, OP_IMM_LOW } },
{ P_LOCAL_N, 2, { M6812_OP_LEAS, OP_PBYTE } },
{ P_LOCAL_2, 1, { M6812_OP_PSHX } },
{ P_LOCAL_2, 1, { M6812_OP_PSHY } },
{ P_LAST, 0 }
};
/* Analyze the sequence of instructions starting at the given address.
Returns a pointer to the sequence when it is recognized and
the optional value (constant/address) associated with it. */
static struct insn_sequence *
m68hc11_analyze_instruction (struct gdbarch *gdbarch,
struct insn_sequence *seq, CORE_ADDR pc,
CORE_ADDR *val)
{
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
unsigned char buffer[MAX_CODES];
unsigned bufsize;
unsigned j;
CORE_ADDR cur_val;
short v = 0;
bufsize = 0;
for (; seq->type != P_LAST; seq++)
{
cur_val = 0;
for (j = 0; j < seq->length; j++)
{
if (bufsize < j + 1)
{
buffer[bufsize] = read_memory_unsigned_integer (pc + bufsize,
1, byte_order);
bufsize++;
}
/* Continue while we match the opcode. */
if (seq->code[j] == buffer[j])
continue;
if ((seq->code[j] & 0xf00) == 0)
break;
/* Extract a sequence parameter (address or constant). */
switch (seq->code[j])
{
case OP_DIRECT:
cur_val = (CORE_ADDR) buffer[j];
break;
case OP_IMM_HIGH:
cur_val = cur_val & 0x0ff;
cur_val |= (buffer[j] << 8);
break;
case OP_IMM_LOW:
cur_val &= 0x0ff00;
cur_val |= buffer[j];
break;
case OP_PBYTE:
if ((buffer[j] & 0xE0) == 0x80)
{
v = buffer[j] & 0x1f;
if (v & 0x10)
v |= 0xfff0;
}
else if ((buffer[j] & 0xfe) == 0xf0)
{
v = read_memory_unsigned_integer (pc + j + 1, 1, byte_order);
if (buffer[j] & 1)
v |= 0xff00;
}
else if (buffer[j] == 0xf2)
{
v = read_memory_unsigned_integer (pc + j + 1, 2, byte_order);
}
cur_val = v;
break;
}
}
/* We have a full match. */
if (j == seq->length)
{
*val = cur_val;
return seq;
}
}
return 0;
}
/* Return the instruction that the function at the PC is using. */
static enum insn_return_kind
m68hc11_get_return_insn (CORE_ADDR pc)
{
struct bound_minimal_symbol sym;
/* A flag indicating that this is a STO_M68HC12_FAR or STO_M68HC12_INTERRUPT
function is stored by elfread.c in the high bit of the info field.
Use this to decide which instruction the function uses to return. */
sym = lookup_minimal_symbol_by_pc (pc);
if (sym.minsym == 0)
return RETURN_RTS;
if (MSYMBOL_IS_RTC (sym.minsym))
return RETURN_RTC;
else if (MSYMBOL_IS_RTI (sym.minsym))
return RETURN_RTI;
else
return RETURN_RTS;
}
/* Analyze the function prologue to find some information
about the function:
- the PC of the first line (for m68hc11_skip_prologue)
- the offset of the previous frame saved address (from current frame)
- the soft registers which are pushed. */
static CORE_ADDR
m68hc11_scan_prologue (struct gdbarch *gdbarch, CORE_ADDR pc,
CORE_ADDR current_pc, struct m68hc11_unwind_cache *info)
{
LONGEST save_addr;
CORE_ADDR func_end;
int size;
int found_frame_point;
int saved_reg;
int done = 0;
struct insn_sequence *seq_table;
info->size = 0;
info->sp_offset = 0;
if (pc >= current_pc)
return current_pc;
size = 0;
m68hc11_initialize_register_info ();
if (pc == 0)
{
info->size = 0;
return pc;
}
m68gc11_gdbarch_tdep *tdep = gdbarch_tdep<m68gc11_gdbarch_tdep> (gdbarch);
seq_table = tdep->prologue;
/* The 68hc11 stack is as follows:
| |
+-----------+
| |
| args |
| |
+-----------+
| PC-return |
+-----------+
| Old frame |
+-----------+
| |
| Locals |
| |
+-----------+ <--- current frame
| |
With most processors (like 68K) the previous frame can be computed
easily because it is always at a fixed offset (see link/unlink).
That is, locals are accessed with negative offsets, arguments are
accessed with positive ones. Since 68hc11 only supports offsets
in the range [0..255], the frame is defined at the bottom of
locals (see picture).
The purpose of the analysis made here is to find out the size
of locals in this function. An alternative to this is to use
DWARF2 info. This would be better but I don't know how to
access dwarf2 debug from this function.
Walk from the function entry point to the point where we save
the frame. While walking instructions, compute the size of bytes
which are pushed. This gives us the index to access the previous
frame.
We limit the search to 128 bytes so that the algorithm is bounded
in case of random and wrong code. We also stop and abort if
we find an instruction which is not supposed to appear in the
prologue (as generated by gcc 2.95, 2.96). */
func_end = pc + 128;
found_frame_point = 0;
info->size = 0;
save_addr = 0;
while (!done && pc + 2 < func_end)
{
struct insn_sequence *seq;
CORE_ADDR val;
seq = m68hc11_analyze_instruction (gdbarch, seq_table, pc, &val);
if (seq == 0)
break;
/* If we are within the instruction group, we can't advance the
pc nor the stack offset. Otherwise the caller's stack computed
from the current stack can be wrong. */
if (pc + seq->length > current_pc)
break;
pc = pc + seq->length;
if (seq->type == P_SAVE_REG)
{
if (found_frame_point)
{
saved_reg = m68hc11_which_soft_register (val);
if (saved_reg < 0)
break;
save_addr -= 2;
if (info->saved_regs)
info->saved_regs[saved_reg].set_addr (save_addr);
}
else
{
size += 2;
}
}
else if (seq->type == P_SET_FRAME)
{
found_frame_point = 1;
info->size = size;
}
else if (seq->type == P_LOCAL_1)
{
size += 1;
}
else if (seq->type == P_LOCAL_2)
{
size += 2;
}
else if (seq->type == P_LOCAL_N)
{
/* Stack pointer is decremented for the allocation. */
if (val & 0x8000)
size -= (int) (val) | 0xffff0000;
else
size -= val;
}
}
if (found_frame_point == 0)
info->sp_offset = size;
else
info->sp_offset = -1;
return pc;
}
static CORE_ADDR
m68hc11_skip_prologue (struct gdbarch *gdbarch, CORE_ADDR pc)
{
CORE_ADDR func_addr, func_end;
struct symtab_and_line sal;
struct m68hc11_unwind_cache tmp_cache = { 0 };
/* If we have line debugging information, then the end of the
prologue should be the first assembly instruction of the
first source line. */
if (find_pc_partial_function (pc, NULL, &func_addr, &func_end))
{
sal = find_pc_line (func_addr, 0);
if (sal.end && sal.end < func_end)
return sal.end;
}
pc = m68hc11_scan_prologue (gdbarch, pc, (CORE_ADDR) -1, &tmp_cache);
return pc;
}
/* Put here the code to store, into fi->saved_regs, the addresses of
the saved registers of frame described by FRAME_INFO. This
includes special registers such as pc and fp saved in special ways
in the stack frame. sp is even more special: the address we return
for it IS the sp for the next frame. */
static struct m68hc11_unwind_cache *
m68hc11_frame_unwind_cache (frame_info_ptr this_frame,
void **this_prologue_cache)
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
ULONGEST prev_sp;
ULONGEST this_base;
struct m68hc11_unwind_cache *info;
CORE_ADDR current_pc;
int i;
if ((*this_prologue_cache))
return (struct m68hc11_unwind_cache *) (*this_prologue_cache);
info = FRAME_OBSTACK_ZALLOC (struct m68hc11_unwind_cache);
(*this_prologue_cache) = info;
info->saved_regs = trad_frame_alloc_saved_regs (this_frame);
info->pc = get_frame_func (this_frame);
info->size = 0;
info->return_kind = m68hc11_get_return_insn (info->pc);
/* The SP was moved to the FP. This indicates that a new frame
was created. Get THIS frame's FP value by unwinding it from
the next frame. */
this_base = get_frame_register_unsigned (this_frame, SOFT_FP_REGNUM);
if (this_base == 0)
{
info->base = 0;
return info;
}
current_pc = get_frame_pc (this_frame);
if (info->pc != 0)
m68hc11_scan_prologue (gdbarch, info->pc, current_pc, info);
info->saved_regs[HARD_PC_REGNUM].set_addr (info->size);
if (info->sp_offset != (CORE_ADDR) -1)
{
info->saved_regs[HARD_PC_REGNUM].set_addr (info->sp_offset);
this_base = get_frame_register_unsigned (this_frame, HARD_SP_REGNUM);
prev_sp = this_base + info->sp_offset + 2;
this_base += stack_correction (gdbarch);
}
else
{
/* The FP points at the last saved register. Adjust the FP back
to before the first saved register giving the SP. */
prev_sp = this_base + info->size + 2;
this_base += stack_correction (gdbarch);
if (soft_regs[SOFT_FP_REGNUM].name)
info->saved_regs[SOFT_FP_REGNUM].set_addr (info->size - 2);
}
if (info->return_kind == RETURN_RTC)
{
prev_sp += 1;
info->saved_regs[HARD_PAGE_REGNUM].set_addr (info->size);
info->saved_regs[HARD_PC_REGNUM].set_addr (info->size + 1);
}
else if (info->return_kind == RETURN_RTI)
{
prev_sp += 7;
info->saved_regs[HARD_CCR_REGNUM].set_addr (info->size);
info->saved_regs[HARD_D_REGNUM].set_addr (info->size + 1);
info->saved_regs[HARD_X_REGNUM].set_addr (info->size + 3);
info->saved_regs[HARD_Y_REGNUM].set_addr (info->size + 5);
info->saved_regs[HARD_PC_REGNUM].set_addr (info->size + 7);
}
/* Add 1 here to adjust for the post-decrement nature of the push
instruction. */
info->prev_sp = prev_sp;
info->base = this_base;
/* Adjust all the saved registers so that they contain addresses and not
offsets. */
for (i = 0; i < gdbarch_num_cooked_regs (gdbarch); i++)
if (info->saved_regs[i].is_addr ())
{
info->saved_regs[i].set_addr (info->saved_regs[i].addr () + this_base);
}
/* The previous frame's SP needed to be computed. Save the computed
value. */
info->saved_regs[HARD_SP_REGNUM].set_value (info->prev_sp);
return info;
}
/* Given a GDB frame, determine the address of the calling function's
frame. This will be used to create a new GDB frame struct. */
static void
m68hc11_frame_this_id (frame_info_ptr this_frame,
void **this_prologue_cache,
struct frame_id *this_id)
{
struct m68hc11_unwind_cache *info
= m68hc11_frame_unwind_cache (this_frame, this_prologue_cache);
CORE_ADDR base;
CORE_ADDR func;
struct frame_id id;
/* The FUNC is easy. */
func = get_frame_func (this_frame);
/* Hopefully the prologue analysis either correctly determined the
frame's base (which is the SP from the previous frame), or set
that base to "NULL". */
base = info->prev_sp;
if (base == 0)
return;
id = frame_id_build (base, func);
(*this_id) = id;
}
static struct value *
m68hc11_frame_prev_register (frame_info_ptr this_frame,
void **this_prologue_cache, int regnum)
{
struct value *value;
struct m68hc11_unwind_cache *info
= m68hc11_frame_unwind_cache (this_frame, this_prologue_cache);
value = trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
/* Take into account the 68HC12 specific call (PC + page). */
if (regnum == HARD_PC_REGNUM
&& info->return_kind == RETURN_RTC
&& use_page_register (get_frame_arch (this_frame)))
{
CORE_ADDR pc = value_as_long (value);
if (pc >= 0x08000 && pc < 0x0c000)
{
CORE_ADDR page;
release_value (value);
value = trad_frame_get_prev_register (this_frame, info->saved_regs,
HARD_PAGE_REGNUM);
page = value_as_long (value);
release_value (value);
pc -= 0x08000;
pc += ((page & 0x0ff) << 14);
pc += 0x1000000;
return frame_unwind_got_constant (this_frame, regnum, pc);
}
}
return value;
}
static const struct frame_unwind m68hc11_frame_unwind = {
"m68hc11 prologue",
NORMAL_FRAME,
default_frame_unwind_stop_reason,
m68hc11_frame_this_id,
m68hc11_frame_prev_register,
NULL,
default_frame_sniffer
};
static CORE_ADDR
m68hc11_frame_base_address (frame_info_ptr this_frame, void **this_cache)
{
struct m68hc11_unwind_cache *info
= m68hc11_frame_unwind_cache (this_frame, this_cache);
return info->base;
}
static CORE_ADDR
m68hc11_frame_args_address (frame_info_ptr this_frame, void **this_cache)
{
CORE_ADDR addr;
struct m68hc11_unwind_cache *info
= m68hc11_frame_unwind_cache (this_frame, this_cache);
addr = info->base + info->size;
if (info->return_kind == RETURN_RTC)
addr += 1;
else if (info->return_kind == RETURN_RTI)
addr += 7;
return addr;
}
static const struct frame_base m68hc11_frame_base = {
&m68hc11_frame_unwind,
m68hc11_frame_base_address,
m68hc11_frame_base_address,
m68hc11_frame_args_address
};
/* Assuming THIS_FRAME is a dummy, return the frame ID of that dummy
frame. The frame ID's base needs to match the TOS value saved by
save_dummy_frame_tos(), and the PC match the dummy frame's breakpoint. */
static struct frame_id
m68hc11_dummy_id (struct gdbarch *gdbarch, frame_info_ptr this_frame)
{
ULONGEST tos;
CORE_ADDR pc = get_frame_pc (this_frame);
tos = get_frame_register_unsigned (this_frame, SOFT_FP_REGNUM);
tos += 2;
return frame_id_build (tos, pc);
}
/* Get and print the register from the given frame. */
static void
m68hc11_print_register (struct gdbarch *gdbarch, struct ui_file *file,
frame_info_ptr frame, int regno)