binutils-gdb/gdb/z8k-tdep.c

432 lines
10 KiB
C

/* Target-machine dependent code for Zilog Z8000, for GDB.
Copyright (C) 1992, 1993, 1994 Free Software Foundation, Inc.
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 2 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, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/*
Contributed by Steve Chamberlain
sac@cygnus.com
*/
#include "defs.h"
#include "frame.h"
#include "obstack.h"
#include "symtab.h"
#include "gdbcmd.h"
#include "gdbtypes.h"
#include "dis-asm.h"
#include "gdbcore.h"
#include "value.h" /* For read_register() */
static int read_memory_pointer (CORE_ADDR x);
/* Return the saved PC from this frame.
If the frame has a memory copy of SRP_REGNUM, use that. If not,
just use the register SRP_REGNUM itself. */
CORE_ADDR
z8k_frame_saved_pc (struct frame_info *frame)
{
return read_memory_pointer (frame->frame + (BIG ? 4 : 2));
}
#define IS_PUSHL(x) (BIG ? ((x & 0xfff0) == 0x91e0):((x & 0xfff0) == 0x91F0))
#define IS_PUSHW(x) (BIG ? ((x & 0xfff0) == 0x93e0):((x & 0xfff0)==0x93f0))
#define IS_MOVE_FP(x) (BIG ? x == 0xa1ea : x == 0xa1fa)
#define IS_MOV_SP_FP(x) (BIG ? x == 0x94ea : x == 0x0d76)
#define IS_SUB2_SP(x) (x==0x1b87)
#define IS_MOVK_R5(x) (x==0x7905)
#define IS_SUB_SP(x) ((x & 0xffff) == 0x020f)
#define IS_PUSH_FP(x) (BIG ? (x == 0x93ea) : (x == 0x93fa))
/* work out how much local space is on the stack and
return the pc pointing to the first push */
static CORE_ADDR
skip_adjust (CORE_ADDR pc, int *size)
{
*size = 0;
if (IS_PUSH_FP (read_memory_short (pc))
&& IS_MOV_SP_FP (read_memory_short (pc + 2)))
{
/* This is a function with an explict frame pointer */
pc += 4;
*size += 2; /* remember the frame pointer */
}
/* remember any stack adjustment */
if (IS_SUB_SP (read_memory_short (pc)))
{
*size += read_memory_short (pc + 2);
pc += 4;
}
return pc;
}
static CORE_ADDR examine_frame (CORE_ADDR, CORE_ADDR * regs, CORE_ADDR);
static CORE_ADDR
examine_frame (CORE_ADDR pc, CORE_ADDR *regs, CORE_ADDR sp)
{
int w = read_memory_short (pc);
int offset = 0;
int regno;
for (regno = 0; regno < NUM_REGS; regno++)
regs[regno] = 0;
while (IS_PUSHW (w) || IS_PUSHL (w))
{
/* work out which register is being pushed to where */
if (IS_PUSHL (w))
{
regs[w & 0xf] = offset;
regs[(w & 0xf) + 1] = offset + 2;
offset += 4;
}
else
{
regs[w & 0xf] = offset;
offset += 2;
}
pc += 2;
w = read_memory_short (pc);
}
if (IS_MOVE_FP (w))
{
/* We know the fp */
}
else if (IS_SUB_SP (w))
{
/* Subtracting a value from the sp, so were in a function
which needs stack space for locals, but has no fp. We fake up
the values as if we had an fp */
regs[FP_REGNUM] = sp;
}
else
{
/* This one didn't have an fp, we'll fake it up */
regs[SP_REGNUM] = sp;
}
/* stack pointer contains address of next frame */
/* regs[fp_regnum()] = fp; */
regs[SP_REGNUM] = sp;
return pc;
}
CORE_ADDR
z8k_skip_prologue (CORE_ADDR start_pc)
{
CORE_ADDR dummy[NUM_REGS];
return examine_frame (start_pc, dummy, 0);
}
CORE_ADDR
z8k_addr_bits_remove (CORE_ADDR addr)
{
return (addr & PTR_MASK);
}
static int
read_memory_pointer (CORE_ADDR x)
{
return read_memory_integer (ADDR_BITS_REMOVE (x), BIG ? 4 : 2);
}
CORE_ADDR
z8k_frame_chain (struct frame_info *thisframe)
{
if (thisframe->prev == 0)
{
/* This is the top of the stack, let's get the sp for real */
}
if (!inside_entry_file (thisframe->pc))
{
return read_memory_pointer (thisframe->frame);
}
return 0;
}
void
init_frame_pc (void)
{
internal_error (__FILE__, __LINE__, "failed internal consistency check");
}
/* Put here the code to store, into a struct frame_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. */
void
z8k_frame_init_saved_regs (struct frame_info *frame_info)
{
CORE_ADDR pc;
int w;
frame_saved_regs_zalloc (frame_info);
pc = get_pc_function_start (frame_info->pc);
/* wander down the instruction stream */
examine_frame (pc, frame_info->saved_regs, frame_info->frame);
}
void
z8k_push_dummy_frame (void)
{
internal_error (__FILE__, __LINE__, "failed internal consistency check");
}
int
gdb_print_insn_z8k (bfd_vma memaddr, disassemble_info *info)
{
if (BIG)
return print_insn_z8001 (memaddr, info);
else
return print_insn_z8002 (memaddr, info);
}
/* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
is not the address of a valid instruction, the address of the next
instruction beyond ADDR otherwise. *PWORD1 receives the first word
of the instruction. */
CORE_ADDR
NEXT_PROLOGUE_INSN (CORE_ADDR addr, CORE_ADDR lim, short *pword1)
{
char buf[2];
if (addr < lim + 8)
{
read_memory (addr, buf, 2);
*pword1 = extract_signed_integer (buf, 2);
return addr + 2;
}
return 0;
}
#if 0
/* Put here the code to store, into a struct frame_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.
We cache the result of doing this in the frame_cache_obstack, since
it is fairly expensive. */
void
frame_find_saved_regs (struct frame_info *fip, struct frame_saved_regs *fsrp)
{
int locals;
CORE_ADDR pc;
CORE_ADDR adr;
int i;
memset (fsrp, 0, sizeof *fsrp);
pc = skip_adjust (get_pc_function_start (fip->pc), &locals);
{
adr = FRAME_FP (fip) - locals;
for (i = 0; i < 8; i++)
{
int word = read_memory_short (pc);
pc += 2;
if (IS_PUSHL (word))
{
fsrp->regs[word & 0xf] = adr;
fsrp->regs[(word & 0xf) + 1] = adr - 2;
adr -= 4;
}
else if (IS_PUSHW (word))
{
fsrp->regs[word & 0xf] = adr;
adr -= 2;
}
else
break;
}
}
fsrp->regs[PC_REGNUM] = fip->frame + 4;
fsrp->regs[FP_REGNUM] = fip->frame;
}
#endif
int
z8k_saved_pc_after_call (struct frame_info *frame)
{
return ADDR_BITS_REMOVE
(read_memory_integer (read_register (SP_REGNUM), PTR_SIZE));
}
void
extract_return_value (struct type *type, char *regbuf, char *valbuf)
{
int b;
int len = TYPE_LENGTH (type);
for (b = 0; b < len; b += 2)
{
int todo = len - b;
if (todo > 2)
todo = 2;
memcpy (valbuf + b, regbuf + b, todo);
}
}
void
write_return_value (struct type *type, char *valbuf)
{
int reg;
int len;
for (len = 0; len < TYPE_LENGTH (type); len += 2)
write_register_bytes (REGISTER_BYTE (len / 2 + 2), valbuf + len, 2);
}
void
store_struct_return (CORE_ADDR addr, CORE_ADDR sp)
{
write_register (2, addr);
}
void
z8k_print_register_hook (int regno)
{
if ((regno & 1) == 0 && regno < 16)
{
unsigned short l[2];
read_relative_register_raw_bytes (regno, (char *) (l + 0));
read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
printf_unfiltered ("\t");
printf_unfiltered ("%04x%04x", l[0], l[1]);
}
if ((regno & 3) == 0 && regno < 16)
{
unsigned short l[4];
read_relative_register_raw_bytes (regno, (char *) (l + 0));
read_relative_register_raw_bytes (regno + 1, (char *) (l + 1));
read_relative_register_raw_bytes (regno + 2, (char *) (l + 2));
read_relative_register_raw_bytes (regno + 3, (char *) (l + 3));
printf_unfiltered ("\t");
printf_unfiltered ("%04x%04x%04x%04x", l[0], l[1], l[2], l[3]);
}
if (regno == 15)
{
unsigned short rval;
int i;
read_relative_register_raw_bytes (regno, (char *) (&rval));
printf_unfiltered ("\n");
for (i = 0; i < 10; i += 2)
{
printf_unfiltered ("(sp+%d=%04x)", i,
(unsigned int)read_memory_short (rval + i));
}
}
}
void
z8k_pop_frame (void)
{
}
struct cmd_list_element *setmemorylist;
void
z8k_set_pointer_size (int newsize)
{
static int oldsize = 0;
if (oldsize != newsize)
{
printf_unfiltered ("pointer size set to %d bits\n", newsize);
oldsize = newsize;
if (newsize == 32)
{
BIG = 1;
}
else
{
BIG = 0;
}
/* FIXME: This code should be using the GDBARCH framework to
handle changed type sizes. If this problem is ever fixed
(the direct reference to _initialize_gdbtypes() below
eliminated) then Makefile.in should be updated so that
z8k-tdep.c is again compiled with -Werror. */
_initialize_gdbtypes ();
}
}
static void
segmented_command (char *args, int from_tty)
{
z8k_set_pointer_size (32);
}
static void
unsegmented_command (char *args, int from_tty)
{
z8k_set_pointer_size (16);
}
static void
set_memory (char *args, int from_tty)
{
printf_unfiltered ("\"set memory\" must be followed by the name of a memory subcommand.\n");
help_list (setmemorylist, "set memory ", -1, gdb_stdout);
}
void
_initialize_z8ktdep (void)
{
tm_print_insn = gdb_print_insn_z8k;
add_prefix_cmd ("memory", no_class, set_memory,
"set the memory model", &setmemorylist, "set memory ", 0,
&setlist);
add_cmd ("segmented", class_support, segmented_command,
"Set segmented memory model.", &setmemorylist);
add_cmd ("unsegmented", class_support, unsegmented_command,
"Set unsegmented memory model.", &setmemorylist);
}