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Stan Shebs
1999-04-16 01:34:07 +00:00
parent 1730ec6b18
commit 071ea11e85
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gdb/m68k-tdep.c
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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 "frame.h"
#include "symtab.h"
/* 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);
#if defined (HAVE_68881)
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);
}
#endif
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 FRAME frame = get_current_frame ();
register CORE_ADDR fp;
register int regnum;
struct frame_saved_regs fsr;
struct frame_info *fi;
char raw_buffer[12];
fi = get_frame_info (frame);
fp = fi -> frame;
get_frame_saved_regs (fi, &fsr);
#if defined (HAVE_68881)
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);
}
}
#endif
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 ();
set_current_frame (create_new_frame (read_register (FP_REGNUM),
read_pc ()));
}
/* 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 == 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);
}
void
m68k_find_saved_regs (frame_info, saved_regs)
struct frame_info *frame_info;
struct frame_saved_regs *saved_regs;
{
register int regnum;
register int regmask;
register CORE_ADDR next_addr;
register CORE_ADDR pc;
/* First possible address for a pc in a call dummy for this frame. */
CORE_ADDR possible_call_dummy_start =
(frame_info)->frame - CALL_DUMMY_LENGTH - FP_REGNUM*4 - 4
#if defined (HAVE_68881)
- 8*12
#endif
;
int nextinsn;
memset (saved_regs, 0, sizeof (*saved_regs));
if ((frame_info)->pc >= possible_call_dummy_start
&& (frame_info)->pc <= (frame_info)->frame)
{
/* It is a call dummy. We could just stop now, since we know
what the call dummy saves and where. But this code proceeds
to parse the "prologue" which is part of the call dummy.
This is needlessly complex, confusing, and also is the only
reason that the call dummy is customized based on HAVE_68881.
FIXME. */
next_addr = (frame_info)->frame;
pc = possible_call_dummy_start;
}
else
{
pc = get_pc_function_start ((frame_info)->pc);
/* Verify we have a link a6 instruction next;
if not we lose. If we win, find the address above the saved
regs using the amount of storage from the link instruction. */
if (044016 == read_memory_integer (pc, 2))
next_addr = (frame_info)->frame + read_memory_integer (pc += 2, 4), pc+=4;
else if (047126 == read_memory_integer (pc, 2))
next_addr = (frame_info)->frame + read_memory_integer (pc += 2, 2), pc+=2;
else goto lose;
/* If have an addal #-n, sp next, adjust next_addr. */
if ((0177777 & read_memory_integer (pc, 2)) == 0157774)
next_addr += read_memory_integer (pc += 2, 4), pc += 4;
}
regmask = read_memory_integer (pc + 2, 2);
#if defined (HAVE_68881)
/* Here can come an fmovem. Check for it. */
nextinsn = 0xffff & read_memory_integer (pc, 2);
if (0xf227 == nextinsn
&& (regmask & 0xff00) == 0xe000)
{ pc += 4; /* Regmask's low bit is for register fp7, the first pushed */
for (regnum = FP0_REGNUM + 7; regnum >= FP0_REGNUM; regnum--, regmask >>= 1)
if (regmask & 1)
saved_regs->regs[regnum] = (next_addr -= 12);
regmask = read_memory_integer (pc + 2, 2); }
#endif
/* next should be a moveml to (sp) or -(sp) or a movl r,-(sp) */
if (0044327 == read_memory_integer (pc, 2))
{ pc += 4; /* Regmask's low bit is for register 0, the first written */
for (regnum = 0; regnum < 16; regnum++, regmask >>= 1)
if (regmask & 1)
saved_regs->regs[regnum] = (next_addr += 4) - 4; }
else if (0044347 == read_memory_integer (pc, 2))
{
pc += 4; /* Regmask's low bit is for register 15, the first pushed */
for (regnum = 15; regnum >= 0; regnum--, regmask >>= 1)
if (regmask & 1)
saved_regs->regs[regnum] = (next_addr -= 4);
}
else if (0x2f00 == (0xfff0 & read_memory_integer (pc, 2)))
{
regnum = 0xf & read_memory_integer (pc, 2); pc += 2;
saved_regs->regs[regnum] = (next_addr -= 4);
/* gcc, at least, may use a pair of movel instructions when saving
exactly 2 registers. */
if (0x2f00 == (0xfff0 & read_memory_integer (pc, 2)))
{
regnum = 0xf & read_memory_integer (pc, 2);
pc += 2;
saved_regs->regs[regnum] = (next_addr -= 4);
}
}
#if defined (HAVE_68881)
/* fmovemx to index of sp may follow. */
regmask = read_memory_integer (pc + 2, 2);
nextinsn = 0xffff & read_memory_integer (pc, 2);
if (0xf236 == nextinsn
&& (regmask & 0xff00) == 0xf000)
{ pc += 10; /* Regmask's low bit is for register fp0, the first written */
for (regnum = FP0_REGNUM + 7; regnum >= FP0_REGNUM; regnum--, regmask >>= 1)
if (regmask & 1)
saved_regs->regs[regnum] = (next_addr += 12) - 12;
regmask = read_memory_integer (pc + 2, 2); }
#endif
/* clrw -(sp); movw ccr,-(sp) may follow. */
if (0x426742e7 == read_memory_integer (pc, 4))
saved_regs->regs[PS_REGNUM] = (next_addr -= 4);
lose: ;
saved_regs->regs[SP_REGNUM] = (frame_info)->frame + 8;
saved_regs->regs[FP_REGNUM] = (frame_info)->frame;
saved_regs->regs[PC_REGNUM] = (frame_info)->frame + 4;
#ifdef SIG_SP_FP_OFFSET
/* Adjust saved SP_REGNUM for fake _sigtramp frames. */
if (frame_info->signal_handler_caller && frame_info->next)
saved_regs->regs[SP_REGNUM] = frame_info->next->frame + SIG_SP_FP_OFFSET;
#endif
}
#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.
*/
/* 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 *) &registers[REGISTER_BYTE (regi)];
}
}
if ((regno == -1) || (regno == PS_REGNUM))
{
*(regp + R_PS) = *(int *) &registers[REGISTER_BYTE (PS_REGNUM)];
}
if ((regno == -1) || (regno == PC_REGNUM))
{
*(regp + R_PC) = *(int *) &registers[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 *) &registers[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 *) &registers[REGISTER_BYTE (FPC_REGNUM)];
}
if ((regno == -1) || (regno == FPS_REGNUM))
{
fpregsetp -> f_psr = *(int *) &registers[REGISTER_BYTE (FPS_REGNUM)];
}
if ((regno == -1) || (regno == FPI_REGNUM))
{
fpregsetp -> f_fpiaddr = *(int *) &registers[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 GDB_TARGET_IS_SUN3
int op;
op = read_memory_integer (frame->pc, 2);
op &= 0xFFFF;
if (op == P_TRAP)
return read_memory_integer (read_register (SP_REGNUM) + 4, 4);
else
#endif /* GDB_TARGET_IS_SUN3 */
return read_memory_integer (read_register (SP_REGNUM), 4);
}