/* Target-machine dependent code for Zilog Z8000, for GDB.
   Copyright (C) 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.  */

/* 
 Contributed by Steve Chamberlain
                sac@cygnus.com 
 */


#include "defs.h"
#include "frame.h"
#include "obstack.h"
#include "symtab.h"
#include "gdbtypes.h"


/* Return the saved PC from this frame.

   If the frame has a memory copy of SRP_REGNUM, use that.  If not,
   just use the register SRP_REGNUM itself.  */

CORE_ADDR
frame_saved_pc (frame)
FRAME frame;
{
  return ( read_memory_pointer(frame->frame+(BIG ? 4 : 2)));
}

#define IS_PUSHL(x) (BIG ? ((x & 0xfff0) == 0x91e0):((x & 0xfff0) == 0x91F0))
#define IS_PUSHW(x) (BIG ? ((x & 0xfff0) == 0x93e0):((x & 0xfff0)==0x93f0))
#define IS_MOVE_FP(x) (BIG ? x == 0xa1ea : x == 0xa1fa)
#define IS_MOV_SP_FP(x) (BIG ? x == 0x94ea : x == 0x0d76)
#define IS_SUB2_SP(x) (x==0x1b87)
#define IS_MOVK_R5(x) (x==0x7905)
#define IS_SUB_SP(x) ((x & 0xffff) == 0x020f)
#define IS_PUSH_FP(x) (BIG ? (x == 0x93ea) : (x == 0x93fa))


/* work out how much local space is on the stack and 
   return the pc pointing to the first push */

static
CORE_ADDR 
skip_adjust(pc, size)
CORE_ADDR pc;
int *size;
{
  *size = 0;

  if (IS_PUSH_FP(read_memory_short(pc))
      && IS_MOV_SP_FP(read_memory_short(pc+2)))
  {
    /* This is a function with an explict frame pointer */
    pc += 4;
    *size += 2;			/* remember the frame pointer */
  }

  /* remember any stack adjustment */
  if (IS_SUB_SP(read_memory_short(pc)))
  {
    *size += read_memory_short(pc+2);
    pc += 4;
  }
  return pc;
}


int
examine_frame(pc, regs, sp)
CORE_ADDR pc;
struct frame_saved_regs *regs;
CORE_ADDR sp;
{
 int w = read_memory_short(pc);
 int offset = 0;
 int regno;



 for (regno = 0; regno < NUM_REGS; regno++)
  regs->regs[regno] = 0;

  while  (IS_PUSHW(w) || IS_PUSHL(w)) 
  {
    /* work out which register is being pushed to where */
    if (IS_PUSHL(w)) 
    {
      regs->regs[w & 0xf] = offset;
      regs->regs[(w & 0xf) + 1] = offset +2;
      offset += 4;
    }
    else {
      regs->regs[w & 0xf] = offset;
      offset += 2;
    }
    pc += 2;
    w = read_memory_short(pc);
  }

 if (IS_MOVE_FP(w)) 
 {
   /* We know the fp */

 }
 else if (IS_SUB_SP(w))
 {
   /* Subtracting a value from the sp, so were in a function
      which needs stack space for locals, but has no fp.  We fake up
      the values as if we had an fp */
   regs->regs[FP_REGNUM] = sp;
 }
 else
 {
   /* This one didn't have an fp, we'll fake it up */
   regs->regs[SP_REGNUM] = sp;
 }
 /* stack pointer contains address of next frame */
/*  regs->regs[fp_regnum()] = fp;*/
  regs->regs[SP_REGNUM] = sp;
  return pc;
}

CORE_ADDR z8k_skip_prologue(start_pc)
CORE_ADDR start_pc;
{
  struct frame_saved_regs dummy;
  return examine_frame(start_pc, &dummy, 0);
}

CORE_ADDR addr_bits_remove(x)
CORE_ADDR x;
{
  return x & PTR_MASK;
}

read_memory_pointer(x)
CORE_ADDR x;
{

return read_memory_integer(ADDR_BITS_REMOVE(x), BIG ? 4 : 2);
}

FRAME_ADDR
frame_chain (thisframe)
     FRAME thisframe;
{
  if (thisframe->prev == 0) 
  {
    /* This is the top of the stack, let's get the sp for real */
  }
  if (!inside_entry_file ((thisframe)->pc))
  {
return     read_memory_pointer ((thisframe)->frame);
  }

  return 0;
}

init_frame_pc() { abort(); }

/* 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.  */

void get_frame_saved_regs(frame_info, frame_saved_regs) 
     struct frame_info *frame_info;
     struct frame_saved_regs *frame_saved_regs;

{
CORE_ADDR pc;
int w;
bzero(frame_saved_regs, sizeof(*frame_saved_regs));
pc = get_pc_function_start(frame_info->pc);

/* wander down the instruction stream */
examine_frame(pc, frame_saved_regs, frame_info->frame);

}


extract_return_value(valtype, regbuf, valbuf)
struct type *valtype;
char regbuf[REGISTER_BYTES];
char *valbuf;
{ 
  bcopy(regbuf + REGISTER_BYTE(2), valbuf, TYPE_LENGTH(valtype));
}
void z8k_push_dummy_frame() { abort(); }

int print_insn(memaddr, stream)
CORE_ADDR memaddr;
FILE *stream;
{
  char temp[20];
  read_memory (memaddr, temp, 20);
  if (BIG) {
    return print_insn_z8001(memaddr, temp, stream);
  }
  else {
    return print_insn_z8002(memaddr, temp, stream);
  }
}

void
store_return_value()
{
abort();
}
void
store_struct_return() { abort(); }



/* Fetch the instruction at ADDR, returning 0 if ADDR is beyond LIM or
   is not the address of a valid instruction, the address of the next
   instruction beyond ADDR otherwise.  *PWORD1 receives the first word
   of the instruction.*/


CORE_ADDR
NEXT_PROLOGUE_INSN(addr, lim, pword1)
CORE_ADDR addr;
CORE_ADDR lim;
short *pword1;
{
  if (addr < lim+8)   
  {
    read_memory (addr, pword1, sizeof(*pword1));
    SWAP_TARGET_AND_HOST (pword1, sizeof (short));
    return addr + 2;
  }

  return 0;

}


/* 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.

   We cache the result of doing this in the frame_cache_obstack, since
   it is fairly expensive.  */

void
frame_find_saved_regs (fip, fsrp)
     struct frame_info *fip;
     struct frame_saved_regs *fsrp;
{
  int locals;
  CORE_ADDR pc;
  CORE_ADDR adr;
  int i;
  
  memset (fsrp, 0, sizeof *fsrp);

  pc = skip_adjust(get_pc_function_start (fip->pc), &locals);

 {
   adr = fip->frame - locals;
   for (i = 0; i < 8; i++) 
   {
     int word = read_memory_short(pc);
     pc += 2 ;
     if (IS_PUSHL(word)) {
       fsrp->regs[word & 0xf] = adr;
       fsrp->regs[(word & 0xf) + 1] = adr - 2;
       adr -= 4;
     }
     else if (IS_PUSHW(word)) {
       fsrp->regs[word & 0xf] = adr;
       adr -= 2;
     }
     else
      break;
   }

 }
  
  fsrp->regs[PC_REGNUM] = fip->frame + 4;
  fsrp->regs[FP_REGNUM] = fip->frame;

}

void
addr_bits_set() { abort(); }

int
saved_pc_after_call() 
{ 
  return addr_bits_remove(read_memory_integer(read_register(SP_REGNUM), PTR_SIZE));
}

void
print_register_hook(regno)
int regno;
{

  if ((regno & 1)==0 && regno < 16) 
  {
    unsigned    short l[2];
    read_relative_register_raw_bytes(regno, (char *)(l+0));
    read_relative_register_raw_bytes(regno+1, (char *)(l+1));
    printf("\t");
    printf("%04x%04x", l[0],l[1]);
  }

  if ((regno & 3)== 0 && regno < 16)
  {
    unsigned    short l[4];
    read_relative_register_raw_bytes(regno, l+0);
    read_relative_register_raw_bytes(regno+1, l+1);
    read_relative_register_raw_bytes(regno+2, l+2);
    read_relative_register_raw_bytes(regno+3, l+3);

    printf("\t");
    printf("%04x%04x%04x%04x", l[0],l[1],l[2],l[3]);
  }
  if (regno == 15) 
  {
    unsigned    short  rval;
    int i;
    read_relative_register_raw_bytes(regno, (char *)(&rval));

    printf("\n");
    for (i = 0; i < 10; i+=2)   {
      printf("(sp+%d=%04x)",i, read_memory_short(rval+i));
    }
  }
  
}


void
register_convert_to_virtual(regnum, from, to) 
unsigned char *from;
unsigned char *to;
{
    to[0] = from[0];
    to[1] = from[1];
    to[2] = from[2];
    to[3] = from[3];
}

void
register_convert_to_raw(regnum, to, from) 
char *to;
char *from;
{
    to[0] = from[0];
    to[1] = from[1];
    to[2] = from[2];
    to[3] = from[3];
}



void z8k_pop_frame() {  }