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/* Target dependent code for the Motorola 68000 series.
Copyright (C) 1990, 1992 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., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "defs.h"
#include "ieee-float.h"
#include "frame.h"
#include "symtab.h"
const struct ext_format ext_format_68881 = {
/* tot sbyte smask expbyte manbyte */
12, 0, 0x80, 0,1, 4,8 /* mc68881 */
};
/* Push an empty stack frame, to record the current PC, etc. */
void
m68k_push_dummy_frame ()
{
register CORE_ADDR sp = read_register (SP_REGNUM);
register int regnum;
char raw_buffer[12];
sp = push_word (sp, read_register (PC_REGNUM));
sp = push_word (sp, read_register (FP_REGNUM));
write_register (FP_REGNUM, sp);
/* Always save the floating-point registers, whether they exist on
this target or not. */
for (regnum = FP0_REGNUM + 7; regnum >= FP0_REGNUM; regnum--)
{
read_register_bytes (REGISTER_BYTE (regnum), raw_buffer, 12);
sp = push_bytes (sp, raw_buffer, 12);
}
for (regnum = FP_REGNUM - 1; regnum >= 0; regnum--)
{
sp = push_word (sp, read_register (regnum));
}
sp = push_word (sp, read_register (PS_REGNUM));
write_register (SP_REGNUM, sp);
}
/* Discard from the stack the innermost frame,
restoring all saved registers. */
void
m68k_pop_frame ()
{
register struct frame_info *frame = get_current_frame ();
register CORE_ADDR fp;
register int regnum;
struct frame_saved_regs fsr;
struct frame_info *fi;
char raw_buffer[12];
fp = FRAME_FP (frame);
get_frame_saved_regs (frame, &fsr);
for (regnum = FP0_REGNUM + 7 ; regnum >= FP0_REGNUM ; regnum--)
{
if (fsr.regs[regnum])
{
read_memory (fsr.regs[regnum], raw_buffer, 12);
write_register_bytes (REGISTER_BYTE (regnum), raw_buffer, 12);
}
}
for (regnum = FP_REGNUM - 1 ; regnum >= 0 ; regnum--)
{
if (fsr.regs[regnum])
{
write_register (regnum, read_memory_integer (fsr.regs[regnum], 4));
}
}
if (fsr.regs[PS_REGNUM])
{
write_register (PS_REGNUM, read_memory_integer (fsr.regs[PS_REGNUM], 4));
}
write_register (FP_REGNUM, read_memory_integer (fp, 4));
write_register (PC_REGNUM, read_memory_integer (fp + 4, 4));
write_register (SP_REGNUM, fp + 8);
flush_cached_frames ();
}
#ifdef NeXT
/* Function calls that pass into a shared library must pass thru a small
piece of code that ammounts to a jump table. There are several ways
this could go, depending on the shared library implementation (static
or dynamic). In the dynamic case, it may require passing thru a
function pointer that hasn't been resolved by the dynamic link-editor
yet.
We figure out where the trampoline is going to end up, and return
the PC of the final destination. If we aren't in a trampoline, we just
return NULL.
By the way, a peculiar hitherto-undocumented feature of this function
is that if the "name" parameter is NULL, it need only return true or
false (ie. are we looking at a trampoline stub). MVS -- NeXT */
CORE_ADDR
skip_trampoline_code (pc, name)
CORE_ADDR pc;
char *name;
{
CORE_ADDR new_pc = 0;
/* first test: static shlib jumptable */
if (read_memory_integer (pc, 2) == 0x4ef9) /* jmps @x */
return name ? 1 : read_memory_integer (pc+2, 4);
/* second test: dynamic shlib jumptable (1st entry point) */
if (read_memory_integer (pc, 4) == 0x207b0170 && /* moveal xxxx, a0 */
read_memory_integer (pc+8, 2) == 0x4ed0) /* jmps a0@ */
pc = new_pc = name ? 1 : /* use this new pc for third test below */
read_memory_integer (pc + read_memory_integer (pc+4, 4) + 2, 4);
/* and fall thru to do next test (both may succeed) */
/* third test: dynamic shlib table (as yet unresolved entry) */
if (read_memory_integer (pc, 4) == 0x487b0170 && /* pea xxxx */
read_memory_integer (pc+8, 2) == 0x60ff) /* bral yyyy */
new_pc = name ? 1 : (CORE_ADDR) get_symbol_stub_real_address (pc, NULL);
return new_pc;
}
#endif /* NeXT */
/* Given an ip value corresponding to the start of a function,
return the ip of the first instruction after the function
prologue. This is the generic m68k support. Machines which
require something different can override the SKIP_PROLOGUE
macro to point elsewhere.
Some instructions which typically may appear in a function
prologue include:
A link instruction, word form:
link.w %a6,&0 4e56 XXXX
A link instruction, long form:
link.l %fp,&F%1 480e XXXX XXXX
A movm instruction to preserve integer regs:
movm.l &M%1,(4,%sp) 48ef XXXX XXXX
A fmovm instruction to preserve float regs:
fmovm &FPM%1,(FPO%1,%sp) f237 XXXX XXXX XXXX XXXX
Some profiling setup code (FIXME, not recognized yet):
lea.l (.L3,%pc),%a1 43fb XXXX XXXX XXXX
bsr _mcount 61ff XXXX XXXX
*/
#define P_LINK_L 0x480e
#define P_LINK_W 0x4e56
#define P_MOV_L 0x207c
#define P_JSR 0x4eb9
#define P_BSR 0x61ff
#define P_LEA_L 0x43fb
#define P_MOVM_L 0x48ef
#define P_FMOVM 0xf237
#define P_TRAP 0x4e40
CORE_ADDR
m68k_skip_prologue (ip)
CORE_ADDR ip;
{
register CORE_ADDR limit;
struct symtab_and_line sal;
register int op;
/* Find out if there is a known limit for the extent of the prologue.
If so, ensure we don't go past it. If not, assume "infinity". */
sal = find_pc_line (ip, 0);
limit = (sal.end) ? sal.end : (CORE_ADDR) ~0;
while (ip < limit)
{
op = read_memory_integer (ip, 2);
op &= 0xFFFF;
if (op == P_LINK_W)
{
ip += 4; /* Skip link.w */
}
else if (op == 0x4856)
ip += 2; /* Skip pea %fp */
else if (op == 0x2c4f)
ip += 2; /* Skip move.l %sp, %fp */
else if (op == P_LINK_L)
{
ip += 6; /* Skip link.l */
}
else if (op == P_MOVM_L)
{
ip += 6; /* Skip movm.l */
}
else if (op == P_FMOVM)
{
ip += 10; /* Skip fmovm */
}
else
{
break; /* Found unknown code, bail out. */
}
}
return (ip);
}
#ifdef USE_PROC_FS /* Target dependent support for /proc */
#include <sys/procfs.h>
/* The /proc interface divides the target machine's register set up into
two different sets, the general register set (gregset) and the floating
point register set (fpregset). For each set, there is an ioctl to get
the current register set and another ioctl to set the current values.
The actual structure passed through the ioctl interface is, of course,
naturally machine dependent, and is different for each set of registers.
For the m68k for example, the general register set is typically defined
by:
typedef int gregset_t[18];
#define R_D0 0
...
#define R_PS 17
and the floating point set by:
typedef struct fpregset {
int f_pcr;
int f_psr;
int f_fpiaddr;
int f_fpregs[8][3]; (8 regs, 96 bits each)
} fpregset_t;
These routines provide the packing and unpacking of gregset_t and
fpregset_t formatted data.
*/
/* Atari SVR4 has R_SR but not R_PS */
#if !defined (R_PS) && defined (R_SR)
#define R_PS R_SR
#endif
/* Given a pointer to a general register set in /proc format (gregset_t *),
unpack the register contents and supply them as gdb's idea of the current
register values. */
void
supply_gregset (gregsetp)
gregset_t *gregsetp;
{
register int regi;
register greg_t *regp = (greg_t *) gregsetp;
for (regi = 0 ; regi < R_PC ; regi++)
{
supply_register (regi, (char *) (regp + regi));
}
supply_register (PS_REGNUM, (char *) (regp + R_PS));
supply_register (PC_REGNUM, (char *) (regp + R_PC));
}
void
fill_gregset (gregsetp, regno)
gregset_t *gregsetp;
int regno;
{
register int regi;
register greg_t *regp = (greg_t *) gregsetp;
extern char registers[];
for (regi = 0 ; regi < R_PC ; regi++)
{
if ((regno == -1) || (regno == regi))
{
*(regp + regi) = *(int *) ®isters[REGISTER_BYTE (regi)];
}
}
if ((regno == -1) || (regno == PS_REGNUM))
{
*(regp + R_PS) = *(int *) ®isters[REGISTER_BYTE (PS_REGNUM)];
}
if ((regno == -1) || (regno == PC_REGNUM))
{
*(regp + R_PC) = *(int *) ®isters[REGISTER_BYTE (PC_REGNUM)];
}
}
#if defined (FP0_REGNUM)
/* Given a pointer to a floating point register set in /proc format
(fpregset_t *), unpack the register contents and supply them as gdb's
idea of the current floating point register values. */
void
supply_fpregset (fpregsetp)
fpregset_t *fpregsetp;
{
register int regi;
char *from;
for (regi = FP0_REGNUM ; regi < FPC_REGNUM ; regi++)
{
from = (char *) &(fpregsetp -> f_fpregs[regi-FP0_REGNUM][0]);
supply_register (regi, from);
}
supply_register (FPC_REGNUM, (char *) &(fpregsetp -> f_pcr));
supply_register (FPS_REGNUM, (char *) &(fpregsetp -> f_psr));
supply_register (FPI_REGNUM, (char *) &(fpregsetp -> f_fpiaddr));
}
/* Given a pointer to a floating point register set in /proc format
(fpregset_t *), update the register specified by REGNO from gdb's idea
of the current floating point register set. If REGNO is -1, update
them all. */
void
fill_fpregset (fpregsetp, regno)
fpregset_t *fpregsetp;
int regno;
{
int regi;
char *to;
char *from;
extern char registers[];
for (regi = FP0_REGNUM ; regi < FPC_REGNUM ; regi++)
{
if ((regno == -1) || (regno == regi))
{
from = (char *) ®isters[REGISTER_BYTE (regi)];
to = (char *) &(fpregsetp -> f_fpregs[regi-FP0_REGNUM][0]);
memcpy (to, from, REGISTER_RAW_SIZE (regi));
}
}
if ((regno == -1) || (regno == FPC_REGNUM))
{
fpregsetp -> f_pcr = *(int *) ®isters[REGISTER_BYTE (FPC_REGNUM)];
}
if ((regno == -1) || (regno == FPS_REGNUM))
{
fpregsetp -> f_psr = *(int *) ®isters[REGISTER_BYTE (FPS_REGNUM)];
}
if ((regno == -1) || (regno == FPI_REGNUM))
{
fpregsetp -> f_fpiaddr = *(int *) ®isters[REGISTER_BYTE (FPI_REGNUM)];
}
}
#endif /* defined (FP0_REGNUM) */
#endif /* USE_PROC_FS */
#ifdef GET_LONGJMP_TARGET
/* Figure out where the longjmp will land. Slurp the args out of the stack.
We expect the first arg to be a pointer to the jmp_buf structure from which
we extract the pc (JB_PC) that we will land at. The pc is copied into PC.
This routine returns true on success. */
int
get_longjmp_target(pc)
CORE_ADDR *pc;
{
char buf[TARGET_PTR_BIT / TARGET_CHAR_BIT];
CORE_ADDR sp, jb_addr;
sp = read_register(SP_REGNUM);
if (target_read_memory (sp + SP_ARG0, /* Offset of first arg on stack */
buf,
TARGET_PTR_BIT / TARGET_CHAR_BIT))
return 0;
jb_addr = extract_address (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT);
if (target_read_memory (jb_addr + JB_PC * JB_ELEMENT_SIZE, buf,
TARGET_PTR_BIT / TARGET_CHAR_BIT))
return 0;
*pc = extract_address (buf, TARGET_PTR_BIT / TARGET_CHAR_BIT);
return 1;
}
#endif /* GET_LONGJMP_TARGET */
/* Immediately after a function call, return the saved pc before the frame
is setup. For sun3's, we check for the common case of being inside of a
system call, and if so, we know that Sun pushes the call # on the stack
prior to doing the trap. */
CORE_ADDR
m68k_saved_pc_after_call(frame)
struct frame_info *frame;
{
#ifdef SYSCALL_TRAP
int op;
op = read_memory_integer (frame->pc - SYSCALL_TRAP_OFFSET, 2);
if (op == SYSCALL_TRAP)
return read_memory_integer (read_register (SP_REGNUM) + 4, 4);
else
#endif /* SYSCALL_TRAP */
return read_memory_integer (read_register (SP_REGNUM), 4);
}
void
_initialize_m68k_tdep ()
{
tm_print_insn = print_insn_m68k;
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.