binutils-gdb/gdb/tm-68k.h

/* Parameters for execution on a 68000 series machine.
   Copyright (C) 1986, 1987, 1989, 1990 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.  */

/* Generic 68000 stuff, to be included by other tm-*.h files.
   Define HAVE_68881 if that is the case.  */

#if defined (HAVE_68881)
#define IEEE_FLOAT 1
#endif

/* Define the bit, byte, and word ordering of the machine.  */
#define TARGET_BYTE_ORDER BIG_ENDIAN

/* Offset from address of function to start of its code.
   Zero on most machines.  */

#define FUNCTION_START_OFFSET 0

/* Advance PC across any function entry prologue instructions
   to reach some "real" code.  */

#if !defined(SKIP_PROLOGUE)
#define SKIP_PROLOGUE(ip)   {(ip) = m68k_skip_prologue(ip);}
extern CORE_ADDR m68k_skip_prologue ();
#endif

/* Immediately after a function call, return the saved pc.
   Can't always go through the frames for this because on some machines
   the new frame is not set up until the new function executes
   some instructions.  */

#define SAVED_PC_AFTER_CALL(frame) \
read_memory_integer (read_register (SP_REGNUM), 4)

/* Stack grows downward.  */

#define INNER_THAN <

/* Sequence of bytes for breakpoint instruction.
   This is a TRAP instruction.  The last 4 bits (0xf below) is the
   vector.  Systems which don't use 0xf should define BPT_VECTOR
   themselves before including this file.  */

#if !defined (BPT_VECTOR)
#define BPT_VECTOR 0xf
#endif

#if !defined (BREAKPOINT)
#define BREAKPOINT {0x4e, (0x40 | BPT_VECTOR)}
#endif

/* If your kernel resets the pc after the trap happens you may need to
   define this before including this file.  */

#if !defined (DECR_PC_AFTER_BREAK)
#define DECR_PC_AFTER_BREAK 2
#endif

/* Nonzero if instruction at PC is a return instruction.  */
/* Allow any of the return instructions, including a trapv and a return
   from interupt.  */

#define ABOUT_TO_RETURN(pc) ((read_memory_integer (pc, 2) & ~0x3) == 0x4e74)

/* Return 1 if P points to an invalid floating point value.  */

#define INVALID_FLOAT(p, len) 0   /* Just a first guess; not checked */

/* Say how long registers are.  */

#define REGISTER_TYPE long

#if defined (HAVE_68881)
#  if defined (GDB_TARGET_IS_SUN3)
    /* Sun3 status includes fpflags, which shows whether the FPU has been used
       by the process, and whether the FPU was done with an instruction or 
       was interrupted in the middle of a long instruction.  See
       <machine/reg.h>.  */
    /*                      a&d, pc,sr, fp, fpstat, fpflags   */
#    define NUM_REGS 31
#    define REGISTER_BYTES (16*4 + 8 + 8*12 + 3*4 + 4)
#  else /* Not sun3.  */
#    define NUM_REGS 29
#    define REGISTER_BYTES (16*4 + 8 + 8*12 + 3*4)
#  endif /* Not sun3.  */
#else /* No 68881.  */
#  define NUM_REGS 18
#  define REGISTER_BYTES (16*4 + 8)
#endif /* No 68881.  */

/* Index within `registers' of the first byte of the space for
   register N.  */

#if defined (HAVE_68881)
#define REGISTER_BYTE(N)  \
 ((N) >= FPC_REGNUM ? (((N) - FPC_REGNUM) * 4) + 168	\
  : (N) >= FP0_REGNUM ? (((N) - FP0_REGNUM) * 12) + 72	\
  : (N) * 4)

/* Number of bytes of storage in the actual machine representation
   for register N.  On the 68000, all regs are 4 bytes
   except the floating point regs which are 12 bytes.  */
/* Note that the unsigned cast here forces the result of the
   subtraction to very high positive values if N < FP0_REGNUM */

#define REGISTER_RAW_SIZE(N) (((unsigned)(N) - FP0_REGNUM) < 8 ? 12 : 4)

/* Number of bytes of storage in the program's representation
   for register N.  On the 68000, all regs are 4 bytes
   except the floating point regs which are 8-byte doubles.  */

#define REGISTER_VIRTUAL_SIZE(N) (((unsigned)(N) - FP0_REGNUM) < 8 ? 8 : 4)

/* Largest value REGISTER_RAW_SIZE can have.  */

#define MAX_REGISTER_RAW_SIZE 12

/* Largest value REGISTER_VIRTUAL_SIZE can have.  */

#define MAX_REGISTER_VIRTUAL_SIZE 8

/* Nonzero if register N requires conversion
   from raw format to virtual format.  */

#define REGISTER_CONVERTIBLE(N) (((unsigned)(N) - FP0_REGNUM) < 8)

/* Put the declaration out here because if it's in the macros, PCC
   will complain.  */
extern struct ext_format ext_format_68881;

/* Convert data from raw format for register REGNUM
   to virtual format for register REGNUM.  */

#define REGISTER_CONVERT_TO_VIRTUAL(REGNUM,FROM,TO)	\
{ \
  if ((REGNUM) >= FP0_REGNUM && (REGNUM) < FPC_REGNUM)	\
    ieee_extended_to_double (&ext_format_68881, (FROM), (double *)(TO)); \
  else					\
    bcopy ((FROM), (TO), 4);	\
}

/* Convert data from virtual format for register REGNUM
   to raw format for register REGNUM.  */

#define REGISTER_CONVERT_TO_RAW(REGNUM,FROM,TO)	\
{ \
  if ((REGNUM) >= FP0_REGNUM && (REGNUM) < FPC_REGNUM)	\
    double_to_ieee_extended (&ext_format_68881, (double *)(FROM), (TO)); \
  else					\
    bcopy ((FROM), (TO), 4);	\
}

/* Return the GDB type object for the "standard" data type
   of data in register N.  */
/* Note, for registers which contain addresses return
   pointer to void, not pointer to char, because we don't
   want to attempt to print the string after printing the address.  */
#define REGISTER_VIRTUAL_TYPE(N) \
 (((unsigned)(N) - FP0_REGNUM) < 8 ? builtin_type_double :           \
  (N) == PC_REGNUM || (N) == FP_REGNUM || (N) == SP_REGNUM ?         \
  lookup_pointer_type (builtin_type_void) : builtin_type_int)

#else /* no 68881.  */
/* Index within `registers' of the first byte of the space for
   register N.  */

#define REGISTER_BYTE(N)  ((N) * 4)

/* Number of bytes of storage in the actual machine representation
   for register N.  On the 68000, all regs are 4 bytes.  */

#define REGISTER_RAW_SIZE(N) 4

/* Number of bytes of storage in the program's representation
   for register N.  On the 68000, all regs are 4 bytes.  */

#define REGISTER_VIRTUAL_SIZE(N) 4

/* Largest value REGISTER_RAW_SIZE can have.  */

#define MAX_REGISTER_RAW_SIZE 4

/* Largest value REGISTER_VIRTUAL_SIZE can have.  */

#define MAX_REGISTER_VIRTUAL_SIZE 4

/* Nonzero if register N requires conversion
   from raw format to virtual format.  */

#define REGISTER_CONVERTIBLE(N) 0

/* Convert data from raw format for register REGNUM
   to virtual format for register REGNUM.  */

#define REGISTER_CONVERT_TO_VIRTUAL(REGNUM,FROM,TO)  bcopy ((FROM), (TO), 4);

/* Convert data from virtual format for register REGNUM
   to raw format for register REGNUM.  */

#define REGISTER_CONVERT_TO_RAW(REGNUM,FROM,TO)  bcopy ((FROM), (TO), 4);

/* Return the GDB type object for the "standard" data type
   of data in register N.  */

#define REGISTER_VIRTUAL_TYPE(N)  builtin_type_int

#endif /* No 68881.  */

/* Initializer for an array of names of registers.
   Entries beyond the first NUM_REGS are ignored.  */

#define REGISTER_NAMES  \
 {"d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7", \
  "a0", "a1", "a2", "a3", "a4", "a5", "fp", "sp", \
  "ps", "pc",  \
  "fp0", "fp1", "fp2", "fp3", "fp4", "fp5", "fp6", "fp7", \
  "fpcontrol", "fpstatus", "fpiaddr", "fpcode", "fpflags" }

/* Register numbers of various important registers.
   Note that some of these values are "real" register numbers,
   and correspond to the general registers of the machine,
   and some are "phony" register numbers which are too large
   to be actual register numbers as far as the user is concerned
   but do serve to get the desired values when passed to read_register.  */

#define A1_REGNUM 9
#define FP_REGNUM 14		/* Contains address of executing stack frame */
#define SP_REGNUM 15		/* Contains address of top of stack */
#define PS_REGNUM 16		/* Contains processor status */
#define PC_REGNUM 17		/* Contains program counter */
#if defined (HAVE_68881)
#define FP0_REGNUM 18		/* Floating point register 0 */
#define FPC_REGNUM 26		/* 68881 control register */
#define FPS_REGNUM 27		/* 68881 status register */
#define FPI_REGNUM 28		/* 68881 iaddr register */
#endif /* 68881.  */

/* Store the address of the place in which to copy the structure the
   subroutine will return.  This is called from call_function. */

#define STORE_STRUCT_RETURN(ADDR, SP) \
  { write_register (A1_REGNUM, (ADDR)); }

/* Extract from an array REGBUF containing the (raw) register state
   a function return value of type TYPE, and copy that, in virtual format,
   into VALBUF.  This is assuming that floating point values are returned
   as doubles in d0/d1.  */

#if !defined (EXTRACT_RETURN_VALUE)
#define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \
  bcopy ((char *)(REGBUF) +						\
	         (TYPE_LENGTH(TYPE) >= 4 ? 0 : 4 - TYPE_LENGTH(TYPE)),	\
	 VALBUF, TYPE_LENGTH(TYPE))
#endif

/* Write into appropriate registers a function return value
   of type TYPE, given in virtual format.  Assumes floats are passed
   in d0/d1.  */

#if !defined (STORE_RETURN_VALUE)
#define STORE_RETURN_VALUE(TYPE,VALBUF) \
  write_register_bytes (0, VALBUF, TYPE_LENGTH (TYPE))
#endif

/* Extract from an array REGBUF containing the (raw) register state
   the address in which a function should return its structure value,
   as a CORE_ADDR (or an expression that can be used as one).  */

#define EXTRACT_STRUCT_VALUE_ADDRESS(REGBUF) (*(CORE_ADDR *)(REGBUF))

/* Describe the pointer in each stack frame to the previous stack frame
   (its caller).  */

/* FRAME_CHAIN takes a frame's nominal address
   and produces the frame's chain-pointer.

   However, if FRAME_CHAIN_VALID returns zero,
   it means the given frame is the outermost one and has no caller.  */

/* In the case of the 68000, the frame's nominal address
   is the address of a 4-byte word containing the calling frame's address.  */

#define FRAME_CHAIN(thisframe)  \
  (outside_startup_file ((thisframe)->pc) ? \
   read_memory_integer ((thisframe)->frame, 4) :\
   0)

#if defined (FRAME_CHAIN_VALID_ALTERNATE)

/* Use the alternate method of avoiding running up off the end of
   the frame chain or following frames back into the startup code.
   See the comments in blockframe.c */
   
#define FRAME_CHAIN_VALID(chain, thisframe)	\
  (chain != 0 					\
   && !(inside_main_scope ((thisframe)->pc))	\
   && !(inside_entry_scope ((thisframe)->pc)))

#else

#define FRAME_CHAIN_VALID(chain, thisframe) \
  (chain != 0 && outside_startup_file (FRAME_SAVED_PC (thisframe)))

#endif	/* FRAME_CHAIN_VALID_ALTERNATE */

/* Define other aspects of the stack frame.  */

/* A macro that tells us whether the function invocation represented
   by FI does not have a frame on the stack associated with it.  If it
   does not, FRAMELESS is set to 1, else 0.  */
#define FRAMELESS_FUNCTION_INVOCATION(FI, FRAMELESS) \
  (FRAMELESS) = frameless_look_for_prologue(FI)

#define FRAME_SAVED_PC(FRAME) (read_memory_integer ((FRAME)->frame + 4, 4))

#define FRAME_ARGS_ADDRESS(fi) ((fi)->frame)

#define FRAME_LOCALS_ADDRESS(fi) ((fi)->frame)

/* Set VAL to the number of args passed to frame described by FI.
   Can set VAL to -1, meaning no way to tell.  */

/* We can't tell how many args there are
   now that the C compiler delays popping them.  */
#if !defined (FRAME_NUM_ARGS)
#define FRAME_NUM_ARGS(val,fi) (val = -1)
#endif

/* Return number of bytes at start of arglist that are not really args.  */

#define FRAME_ARGS_SKIP 8

/* 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.  */

#if !defined (FRAME_FIND_SAVED_REGS)
#if defined (HAVE_68881)
#define FRAME_FIND_SAVED_REGS(frame_info, frame_saved_regs)		\
{ register int regnum;							\
  register int regmask;							\
  register CORE_ADDR next_addr;						\
  register CORE_ADDR pc;						\
  int nextinsn;								\
  bzero (&frame_saved_regs, sizeof frame_saved_regs);			\
  if ((frame_info)->pc >= (frame_info)->frame - CALL_DUMMY_LENGTH - FP_REGNUM*4 - 8*12 - 4 \
      && (frame_info)->pc <= (frame_info)->frame)				\
    { next_addr = (frame_info)->frame;					\
      pc = (frame_info)->frame - CALL_DUMMY_LENGTH - FP_REGNUM * 4 - 8*12 - 4; }\
  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;		\
    }									\
  /* next should be a moveml to (sp) or -(sp) or a movl r,-(sp) */	\
  regmask = read_memory_integer (pc + 2, 2);				\
  /* But before that 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)						\
          (frame_saved_regs).regs[regnum] = (next_addr -= 12);		\
      regmask = read_memory_integer (pc + 2, 2); }			\
  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)						\
          (frame_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)						\
          (frame_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;		\
      (frame_saved_regs).regs[regnum] = (next_addr -= 4); }		\
  /* 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)						\
          (frame_saved_regs).regs[regnum] = (next_addr += 12) - 12;	\
      regmask = read_memory_integer (pc + 2, 2); }			\
  /* clrw -(sp); movw ccr,-(sp) may follow.  */				\
  if (0x426742e7 == read_memory_integer (pc, 4))			\
    (frame_saved_regs).regs[PS_REGNUM] = (next_addr -= 4);		\
  lose: ;								\
  (frame_saved_regs).regs[SP_REGNUM] = (frame_info)->frame + 8;		\
  (frame_saved_regs).regs[FP_REGNUM] = (frame_info)->frame;		\
  (frame_saved_regs).regs[PC_REGNUM] = (frame_info)->frame + 4;		\
}
#else /* no 68881.  */
#define FRAME_FIND_SAVED_REGS(frame_info, frame_saved_regs)		\
{ register int regnum;							\
  register int regmask;							\
  register CORE_ADDR next_addr;						\
  register CORE_ADDR pc;						\
  bzero (&frame_saved_regs, sizeof frame_saved_regs);			\
  if ((frame_info)->pc >= (frame_info)->frame - CALL_DUMMY_LENGTH - FP_REGNUM*4 - 4 \
      && (frame_info)->pc <= (frame_info)->frame)				\
    { next_addr = (frame_info)->frame;					\
      pc = (frame_info)->frame - CALL_DUMMY_LENGTH - FP_REGNUM * 4 - 4; }\
  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;		\
    }									\
  /* next should be a moveml to (sp) or -(sp) or a movl r,-(sp) */	\
  regmask = read_memory_integer (pc + 2, 2);				\
  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)						\
          (frame_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)						\
          (frame_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;		\
      (frame_saved_regs).regs[regnum] = (next_addr -= 4); }		\
  /* clrw -(sp); movw ccr,-(sp) may follow.  */				\
  if (0x426742e7 == read_memory_integer (pc, 4))			\
    (frame_saved_regs).regs[PS_REGNUM] = (next_addr -= 4);		\
  lose: ;								\
  (frame_saved_regs).regs[SP_REGNUM] = (frame_info)->frame + 8;		\
  (frame_saved_regs).regs[FP_REGNUM] = (frame_info)->frame;		\
  (frame_saved_regs).regs[PC_REGNUM] = (frame_info)->frame + 4;		\
}
#endif /* no 68881.  */
#endif /* no FIND_FRAME_SAVED_REGS.  */


/* Things needed for making the inferior call functions.
   It seems like every m68k based machine has almost identical definitions
   in the individual machine's configuration files.  Most other cpu types
   (mips, i386, etc) have routines in their *-tdep.c files to handle this
   for most configurations.  The m68k family should be able to do this as
   well.  These macros can still be overridden when necessary.  */

/* The CALL_DUMMY macro is the sequence of instructions, as disassembled
   by gdb itself:

	fmovemx fp0-fp7,sp@-			0xf227 0xe0ff
	moveml d0-a5,sp@-			0x48e7 0xfffc
	clrw sp@-				0x4267
	movew ccr,sp@-				0x42e7

	/..* The arguments are pushed at this point by GDB;
	no code is needed in the dummy for this.
	The CALL_DUMMY_START_OFFSET gives the position of 
	the following jsr instruction.  *../

	jsr @#0x32323232			0x4eb9 0x3232 0x3232
	addal #0x69696969,sp			0xdffc 0x6969 0x6969
	trap #<your BPT_VECTOR number here>	0x4e4?
	nop					0x4e71

   Note this is CALL_DUMMY_LENGTH bytes (28 for the above example).
   We actually start executing at the jsr, since the pushing of the
   registers is done by PUSH_DUMMY_FRAME.  If this were real code,
   the arguments for the function called by the jsr would be pushed
   between the moveml and the jsr, and we could allow it to execute through.
   But the arguments have to be pushed by GDB after the PUSH_DUMMY_FRAME is
   done, and we cannot allow the moveml to push the registers again lest
   they be taken for the arguments.  */

#if defined (HAVE_68881)

#define CALL_DUMMY {0xf227e0ff, 0x48e7fffc, 0x426742e7, 0x4eb93232, 0x3232dffc, 0x69696969, (0x4e404e71 | (BPT_VECTOR << 16))}
#define CALL_DUMMY_LENGTH 28		/* Size of CALL_DUMMY */
#define CALL_DUMMY_START_OFFSET 12	/* Offset to jsr instruction*/

#else

#define CALL_DUMMY {0x48e7fffc, 0x426742e7, 0x4eb93232, 0x3232dffc, 0x69696969, (0x4e404e71 | (BPT_VECTOR << 16))}
#define CALL_DUMMY_LENGTH 24		/* Size of CALL_DUMMY */
#define CALL_DUMMY_START_OFFSET 8	/* Offset to jsr instruction*/

#endif	/* HAVE_68881 */

/* Insert the specified number of args and function address
   into a call sequence of the above form stored at DUMMYNAME.  */

#define FIX_CALL_DUMMY(dummyname, pc, fun, nargs, args, type, gcc_p)     \
{ *(int *)((char *) dummyname + CALL_DUMMY_START_OFFSET + 2) = fun;  \
  *(int *)((char *) dummyname + CALL_DUMMY_START_OFFSET + 8) = nargs * 4; }

/* Push an empty stack frame, to record the current PC, etc.  */

#define PUSH_DUMMY_FRAME	{ m68k_push_dummy_frame (); }

/* Discard from the stack the innermost frame, restoring all registers.  */

#define POP_FRAME		{ m68k_pop_frame (); }