/*
Date: Thu, 2 Apr 87 00:02:42 EST
From: crl@maxwell.physics.purdue.edu (Charles R. LaBrec)
Message-Id: <8704020502.AA01744@maxwell.physics.purdue.edu>
To: bug-gdb@prep.ai.mit.edu
Subject: gdb for ISI Optimum V

Here is an m-isi-ov.h file for gdb version 2.1.  It supports the 68881
registers, and tracks down the function prologue (since the ISI cc
puts it at the end of the function and branches to it if not
optimizing).  Also included are diffs to core.c, findvar.c, and
inflow.c, since the original code assumed that registers are an int in
the user struct, which isn't the case for 68020's with 68881's (and
not using the NEW_SUN_PTRACE).  I have not fixed the bugs associated
with the other direction (writing registers back to the user struct).
I have also included a diff that turns m68k-pinsn.c into isi-pinsn.c,
which is needed since the 3.05 release of as does not understand
floating point ops, and it compiles incorrectly under "cc -20"

I have used gdb for a while now, and it seems to work relatively well,
but I do not guarantee that it is perfect.  The more that use it, the
faster the bugs will get shaken out.  One bug I know of is not in gdb,
but in the assembler.  It seems to screw up the .stabs of variables.
For externs, this is not important since gdb uses the global symbol
value, but for statics, this makes gdb unable to find them.  I am
currently trying to track it down.

As an aside, I notice that only global functions are used as symbols
to print as relative addresses, i.e. "<function + offset>", and not
static functions, which end up printing as large offsets from the last
global one.  Would there be a problem if static functions were also
recorded as misc functions in read_dbx_symtab?

Charles LaBrec
crl @ maxwell.physics.purdue.edu

  Definitions to make GDB run on a ISI Optimum V (3.05) under 4.2bsd.

   Copyright (C) 1987 Free Software Foundation, Inc.

GDB is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY.  No author or distributor accepts responsibility to anyone
for the consequences of using it or for whether it serves any
particular purpose or works at all, unless he says so in writing.
Refer to the GDB General Public License for full details.

Everyone is granted permission to copy, modify and redistribute GDB,
but only under the conditions described in the GDB General Public
License.  A copy of this license is supposed to have been given to you
along with GDB so you can know your rights and responsibilities.  It
should be in a file named COPYING.  Among other things, the copyright
notice and this notice must be preserved on all copies.

In other words, go ahead and share GDB, but don't try to stop
anyone else from sharing it farther.  Help stamp out software hoarding!
*/


/* Identify this machine */
#ifndef ISI68K
#define ISI68K
#endif

/* Define this if the C compiler puts an underscore at the front
   of external names before giving them to the linker.  */

#define NAMES_HAVE_UNDERSCORE

/* Debugger information will be in DBX format.  */

#define READ_DBX_FORMAT

/* 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.  */

#define SKIP_PROLOGUE(pc)   \
{ register int op = read_memory_integer (pc, 2);	\
  if (op == 0047126)					\
    pc += 4;   /* Skip link #word */			\
  else if (op == 0044016)				\
    pc += 6;   /* Skip link #long */			\
  else if (op == 0060000)				\
    pc += 4;   /* Skip bra #word */			\
  else if (op == 00600377)				\
    pc += 6;   /* skip bra #long */			\
  else if ((op & 0177400) == 0060000)			\
    pc += 2;   /* skip bra #char */			\
}


/* 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)

/* This is the amount to subtract from u.u_ar0
   to get the offset in the core file of the register values.  */

#define KERNEL_U_ADDR 0x10800000

/* Address of end of stack space.  */

#define STACK_END_ADDR 0x10000000

/* Stack grows downward.  */

#define INNER_THAN <

/* Sequence of bytes for breakpoint instruction.  */

#define BREAKPOINT {0x4e, 0x4f}

/* Data segment starts at etext rounded up to DATAROUND in {N,Z}MAGIC files */

#define DATAROUND	0x20000
#define N_DATADDR(hdr)	(hdr.a_magic != OMAGIC ? \
	(hdr.a_text + DATAROUND) & ~(DATAROUND-1) : hdr.a_text)

/* Text segment starts at sizeof (struct exec) in {N,Z}MAGIC files */

#define N_TXTADDR(hdr)	(hdr.a_magic != OMAGIC ? sizeof (struct exec) : 0)

/* Amount PC must be decremented by after a breakpoint.
   This is often the number of bytes in BREAKPOINT
   but not always.  
   On the ISI, the kernel resets the pc to the trap instr */

#define DECR_PC_AFTER_BREAK 0

/* Nonzero if instruction at PC is a return instruction.  */

#define ABOUT_TO_RETURN(pc) (read_memory_integer (pc, 2) == 0x4e75)

/* 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

/* Number of machine registers */

#define NUM_REGS 29

/* Initializer for an array of names of registers.
   There should be NUM_REGS strings in this initializer.  */

#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" }

/* 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 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 */
#define FP0_REGNUM 18		/* Floating point register 0 */
#define FPC_REGNUM 26		/* 68881 control register */

#ifdef BSD43_ISI40D
#define BLOCKFUDGE	0x400000
#else
#define BLOCKFUDGE	0
#endif
#define REGISTER_U_ADDR(addr, blockend, regno)			\
{	blockend -= BLOCKFUDGE;					\
	if (regno < 2) addr = blockend - 0x18 + regno * 4;	\
	else if (regno < 8) addr = blockend - 0x54 + regno * 4;	\
	else if (regno < 10) addr = blockend - 0x30 + regno * 4;\
	else if (regno < 15) addr = blockend - 0x5c + regno * 4;\
	else if (regno < 16) addr = blockend - 0x1c;		\
	else if (regno < 18) addr = blockend - 0x44 + regno * 4;\
	else if (regno < 26) addr = (int) ((struct user *)0)->u_68881_regs \
	    + (regno - 18) * 12;				\
	else if (regno < 29) addr = (int) ((struct user *)0)->u_68881_regs \
	    + 8 * 12 + (regno - 26) * 4;			\
}

/* Total amount of space needed to store our copies of the machine's
   register state, the array `registers'.  */
#define REGISTER_BYTES (16*4+8*12+8+20)

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

#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.  */

#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)

/* 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)	\
    convert_from_68881 ((FROM), (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)	\
    convert_to_68881 ((FROM), (TO));	\
  else					\
    bcopy ((FROM), (TO), 4); }

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

#define REGISTER_VIRTUAL_TYPE(N) \
 (((unsigned)(N) - FP0_REGNUM) < 8 ? builtin_type_double : builtin_type_int)

/* 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.  */

#define EXTRACT_RETURN_VALUE(TYPE,REGBUF,VALBUF) \
  bcopy (REGBUF, VALBUF, TYPE_LENGTH (TYPE))

/* Write into appropriate registers a function return value
   of type TYPE, given in virtual format.  */

#define STORE_RETURN_VALUE(TYPE,VALBUF) \
  write_register_bytes (0, VALBUF, TYPE_LENGTH (TYPE))

/* 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) (*(int *)(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.

   FRAME_CHAIN_COMBINE takes the chain pointer and the frame's nominal address
   and produces the nominal address of the caller frame.

   However, if FRAME_CHAIN_VALID returns zero,
   it means the given frame is the outermost one and has no caller.
   In that case, FRAME_CHAIN_COMBINE is not used.  */

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

#define FRAME_CHAIN(thisframe)  (read_memory_integer (thisframe, 4))

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

#define FRAME_CHAIN_COMBINE(chain, thisframe) (chain)

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

#define FRAME_SAVED_PC(frame) (read_memory_integer (frame + 4, 4))

#define FRAME_ARGS_ADDRESS(fi) (fi.frame)

#define FRAME_LOCALS_ADDRESS(fi) (fi.frame)

/* Return number of args passed to a frame.
   Can return -1, meaning no way to tell.  */

#define FRAME_NUM_ARGS(val, fi)  \
{ register CORE_ADDR pc = FRAME_SAVED_PC (fi.frame);		\
  register int insn = 0177777 & read_memory_integer (pc, 2);	\
  val = 0;							\
  if (insn == 0047757 || insn == 0157374)  /* lea W(sp),sp or addaw #W,sp */ \
    val = read_memory_integer (pc + 2, 2);			\
  else if ((insn & 0170777) == 0050217 /* addql #N, sp */	\
	   || (insn & 0170777) == 0050117)  /* addqw */		\
    { val = (insn >> 9) & 7; if (val == 0) val = 8; }		\
  else if (insn == 0157774) /* addal #WW, sp */			\
    val = read_memory_integer (pc + 2, 4);			\
  val >>= 2; }

/* 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.  */

#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;						\
  register int insn;							\
  register int offset;							\
  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,			\
	 or a branch followed by a link a6 instruction;			\
	 if not we lose.  If we win, find the address above the saved   \
	 regs using the amount of storage from the link instruction.  */\
retry:									\
      insn = read_memory_integer (pc, 2);				\
      if (insn == 044016)						\
	next_addr = (frame_info).frame - read_memory_integer (pc += 2, 4), pc+=4; \
      else if (insn == 047126)						\
	next_addr = (frame_info).frame - read_memory_integer (pc += 2, 2), pc+=2; \
      else if ((insn & 0177400) == 060000)	/* bra insn */		\
	{ offset = insn & 0377;						\
          pc += 2;				/* advance past bra */	\
	  if (offset == 0)			/* bra #word */		\
	    offset = read_memory_integer (pc, 2), pc += 2;		\
	  else if (offset == 0377)		/* bra #long */		\
	    offset = read_memory_integer (pc, 4), pc += 4;		\
	  pc += offset;							\
	  goto retry;							\
      } 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) */	\
  insn = read_memory_integer (pc, 2), pc += 2;				\
  regmask = read_memory_integer (pc, 2);				\
  if ((insn & 0177760) == 022700)	/* movl rn, (sp) */		\
    (frame_saved_regs).regs[(insn&7) + ((insn&010)?8:0)] = next_addr;	\
  else if ((insn & 0177760) == 024700)	/* movl rn, -(sp) */		\
    (frame_saved_regs).regs[(insn&7) + ((insn&010)?8:0)] = next_addr-=4; \
  else if (insn == 0044327)		/* moveml mask, (sp) */		\
    { pc += 2;								\
      /* Regmask's low bit is for register 0, the first written */	\
      next_addr -= 4;							\
      for (regnum = 0; regnum < 16; regnum++, regmask >>= 1)		\
	if (regmask & 1)						\
          (frame_saved_regs).regs[regnum] = (next_addr += 4);		\
  } else if (insn == 0044347)		/* moveml mask, -(sp) */	\
    { pc += 2;								\
      /* 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); }		\
  /* clrw -(sp); movw ccr,-(sp) may follow.  */				\
  if (read_memory_integer (pc, 2) == 041147 				\
      && read_memory_integer (pc+2, 2) == 042347)			\
    (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;		\
}

/* Compensate for lack of `vprintf' function.  */ 
#define vprintf(format, ap) _doprnt (format, ap, stdout) 

/* Things needed for making the inferior call functions.  */

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

#define 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);					\
  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 registers.  */

#define POP_FRAME  \
{ register CORE_ADDR fp = read_register (FP_REGNUM);			\
  register int regnum;							\
  struct frame_saved_regs fsr;						\
  struct frame_info fi;							\
  char raw_buffer[12];							\
  fi = get_frame_info (fp);						\
  get_frame_saved_regs (&fi, &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);					\
}

/* This sequence of words is the instructions
     fmovem #<f0-f7>,-(sp)
     moveml 0xfffc,-(sp)
     clrw -(sp)
     movew ccr,-(sp)
     /..* 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 @#32323232
     addl #69696969,sp
     bpt
     nop
Note this is 24 bytes.
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.  */

#define CALL_DUMMY {0xf227e0ff, 0x48e7fffc, 0x426742e7, 0x4eb93232, 0x3232dffc, 0x69696969, 0x4e4f4e71}

#define CALL_DUMMY_LENGTH 28

#define CALL_DUMMY_START_OFFSET 12

/* 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, fun, nargs)     \
{ *(int *)((char *) dummyname + 20) = nargs * 4;  \
  *(int *)((char *) dummyname + 14) = fun; }

/* Interface definitions for kernel debugger KDB.  */

/* Map machine fault codes into signal numbers.
   First subtract 0, divide by 4, then index in a table.
   Faults for which the entry in this table is 0
   are not handled by KDB; the program's own trap handler
   gets to handle then.  */

#define FAULT_CODE_ORIGIN 0
#define FAULT_CODE_UNITS 4
#define FAULT_TABLE    \
{ 0, 0, 0, 0, SIGTRAP, 0, 0, 0, \
  0, SIGTRAP, 0, 0, 0, 0, 0, SIGKILL, \
  0, 0, 0, 0, 0, 0, 0, 0, \
  SIGILL }

/* Start running with a stack stretching from BEG to END.
   BEG and END should be symbols meaningful to the assembler.
   This is used only for kdb.  */

#define INIT_STACK(beg, end)  \
{ asm (".globl end");         \
  asm ("movl $ end, sp");      \
  asm ("clrl fp"); }

/* Push the frame pointer register on the stack.  */
#define PUSH_FRAME_PTR        \
  asm ("movel fp, -(sp)");

/* Copy the top-of-stack to the frame pointer register.  */
#define POP_FRAME_PTR  \
  asm ("movl (sp), fp");

/* After KDB is entered by a fault, push all registers
   that GDB thinks about (all NUM_REGS of them),
   so that they appear in order of ascending GDB register number.
   The fault code will be on the stack beyond the last register.  */

#define PUSH_REGISTERS        \
{ asm ("clrw -(sp)");	      \
  asm ("pea 10(sp)");	      \
  asm ("movem $ 0xfffe,-(sp)"); }

/* Assuming the registers (including processor status) have been
   pushed on the stack in order of ascending GDB register number,
   restore them and return to the address in the saved PC register.  */

#define POP_REGISTERS          \
{ asm ("subil $8,28(sp)");     \
  asm ("movem (sp),$ 0xffff"); \
  asm ("rte"); }