/* Definitions to target GDB on an ISI Optimum V (3.05) under 4.3bsd.
   Copyright (C) 1987, 1989 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.  */

/* This has not been tested on ISI's running BSD 4.2, but it will probably
   work.  */

/* 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

/*#define STACK_END_ADDR 0x10000000*/
#define STACK_END_ADDR 0xfffe000

/* 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


/* 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);			\
  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; }

/* 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;		\
}

/* 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 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);					\
  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 ();						\
  set_current_frame ( create_new_frame (read_register (FP_REGNUM),	\
					read_pc ())); }

/* 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, pc, fun, nargs, args, type, gcc_p)     \
{ *(int *)((char *) dummyname + 20) = nargs * 4;  \
  *(int *)((char *) dummyname + 14) = fun; }

#define HAVE_68881 1

#include "tm-68k.h"
