/* Simulator for Xilinx MicroBlaze processor
   Copyright 2009-2015 Free Software Foundation, Inc.

   This file is part of GDB, the GNU debugger.

   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 3 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, see <http://www.gnu.org/licenses/>.  */

#include "config.h"
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <sys/times.h>
#include <sys/param.h>
#include <unistd.h>
#include "bfd.h"
#include "gdb/callback.h"
#include "libiberty.h"
#include "gdb/remote-sim.h"
#include "run-sim.h"
#include "sim-main.h"
#include "sim-utils.h"
#include "microblaze-dis.h"


#ifndef NUM_ELEM
#define NUM_ELEM(A) (sizeof (A) / sizeof (A)[0])
#endif

static int target_big_endian = 1;
static unsigned long heap_ptr = 0;
static unsigned long stack_ptr = 0;
host_callback *callback;

static unsigned long
microblaze_extract_unsigned_integer (unsigned char *addr, int len)
{
  unsigned long retval;
  unsigned char *p;
  unsigned char *startaddr = (unsigned char *)addr;
  unsigned char *endaddr = startaddr + len;

  if (len > (int) sizeof (unsigned long))
    printf ("That operation is not available on integers of more than "
	    "%zu bytes.", sizeof (unsigned long));

  /* Start at the most significant end of the integer, and work towards
     the least significant.  */
  retval = 0;

  if (!target_big_endian)
    {
      for (p = endaddr; p > startaddr;)
	retval = (retval << 8) | * -- p;
    }
  else
    {
      for (p = startaddr; p < endaddr;)
	retval = (retval << 8) | * p ++;
    }

  return retval;
}

static void
microblaze_store_unsigned_integer (unsigned char *addr, int len,
				   unsigned long val)
{
  unsigned char *p;
  unsigned char *startaddr = (unsigned char *)addr;
  unsigned char *endaddr = startaddr + len;

  if (!target_big_endian)
    {
      for (p = startaddr; p < endaddr;)
	{
	  *p++ = val & 0xff;
	  val >>= 8;
	}
    }
  else
    {
      for (p = endaddr; p > startaddr;)
	{
	  *--p = val & 0xff;
	  val >>= 8;
	}
    }
}

struct sim_state microblaze_state;

int memcycles = 1;

static SIM_OPEN_KIND sim_kind;
static char *myname;

static int issue_messages = 0;

static void /* INLINE */
wbat (word x, word v)
{
  if (((uword)x) >= CPU.msize)
    {
      if (issue_messages)
	fprintf (stderr, "byte write to 0x%x outside memory range\n", x);

      CPU.exception = SIGSEGV;
    }
  else
    {
      unsigned char *p = CPU.memory + x;
      p[0] = v;
    }
}

static void /* INLINE */
wlat (word x, word v)
{
  if (((uword)x) >= CPU.msize)
    {
      if (issue_messages)
	fprintf (stderr, "word write to 0x%x outside memory range\n", x);

      CPU.exception = SIGSEGV;
    }
  else
    {
      if ((x & 3) != 0)
	{
	  if (issue_messages)
	    fprintf (stderr, "word write to unaligned memory address: 0x%x\n", x);

	  CPU.exception = SIGBUS;
	}
      else if (!target_big_endian)
	{
	  unsigned char *p = CPU.memory + x;
	  p[3] = v >> 24;
	  p[2] = v >> 16;
	  p[1] = v >> 8;
	  p[0] = v;
	}
      else
	{
	  unsigned char *p = CPU.memory + x;
	  p[0] = v >> 24;
	  p[1] = v >> 16;
	  p[2] = v >> 8;
	  p[3] = v;
	}
    }
}

static void /* INLINE */
what (word x, word v)
{
  if (((uword)x) >= CPU.msize)
    {
      if (issue_messages)
	fprintf (stderr, "short write to 0x%x outside memory range\n", x);

      CPU.exception = SIGSEGV;
    }
  else
    {
      if ((x & 1) != 0)
	{
	  if (issue_messages)
	    fprintf (stderr, "short write to unaligned memory address: 0x%x\n",
		     x);

	  CPU.exception = SIGBUS;
	}
      else if (!target_big_endian)
	{
	  unsigned char *p = CPU.memory + x;
	  p[1] = v >> 8;
	  p[0] = v;
	}
      else
	{
	  unsigned char *p = CPU.memory + x;
	  p[0] = v >> 8;
	  p[1] = v;
	}
    }
}

/* Read functions.  */
static int /* INLINE */
rbat (word x)
{
  if (((uword)x) >= CPU.msize)
    {
      if (issue_messages)
	fprintf (stderr, "byte read from 0x%x outside memory range\n", x);

      CPU.exception = SIGSEGV;
      return 0;
    }
  else
    {
      unsigned char *p = CPU.memory + x;
      return p[0];
    }
}

static int /* INLINE */
rlat (word x)
{
  if (((uword) x) >= CPU.msize)
    {
      if (issue_messages)
	fprintf (stderr, "word read from 0x%x outside memory range\n", x);

      CPU.exception = SIGSEGV;
      return 0;
    }
  else
    {
      if ((x & 3) != 0)
	{
	  if (issue_messages)
	    fprintf (stderr, "word read from unaligned address: 0x%x\n", x);

	  CPU.exception = SIGBUS;
	  return 0;
	}
      else if (! target_big_endian)
	{
	  unsigned char *p = CPU.memory + x;
	  return (p[3] << 24) | (p[2] << 16) | (p[1] << 8) | p[0];
	}
      else
	{
	  unsigned char *p = CPU.memory + x;
	  return (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
	}
    }
}

static int /* INLINE */
rhat (word x)
{
  if (((uword)x) >= CPU.msize)
    {
      if (issue_messages)
	fprintf (stderr, "short read from 0x%x outside memory range\n", x);

      CPU.exception = SIGSEGV;
      return 0;
    }
  else
    {
      if ((x & 1) != 0)
	{
	  if (issue_messages)
	    fprintf (stderr, "short read from unaligned address: 0x%x\n", x);

	  CPU.exception = SIGBUS;
	  return 0;
	}
      else if (!target_big_endian)
	{
	  unsigned char *p = CPU.memory + x;
	  return (p[1] << 8) | p[0];
	}
      else
	{
	  unsigned char *p = CPU.memory + x;
	  return (p[0] << 8) | p[1];
	}
    }
}

/* Default to a 8 Mbyte (== 2^23) memory space.  */
static int sim_memory_size = 1 << 23;

#define	MEM_SIZE_FLOOR	64
void
sim_size (int size)
{
  sim_memory_size = size;
  CPU.msize = sim_memory_size;

  if (CPU.memory)
    free (CPU.memory);

  CPU.memory = (unsigned char *) calloc (1, CPU.msize);

  if (!CPU.memory)
    {
      if (issue_messages)
	fprintf (stderr,
		 "Not enough VM for simulation of %ld bytes of RAM\n",
		 CPU.msize);

      CPU.msize = 1;
      CPU.memory = (unsigned char *) calloc (1, 1);
    }
}

static void
init_pointers (void)
{
  if (CPU.msize != (sim_memory_size))
    sim_size (sim_memory_size);
}

static void
set_initial_gprs (void)
{
  int i;
  long space;
  unsigned long memsize;

  init_pointers ();

  /* Set up machine just out of reset.  */
  PC = 0;
  MSR = 0;

  memsize = CPU.msize / (1024 * 1024);

  if (issue_messages > 1)
    fprintf (stderr, "Simulated memory of %ld Mbytes (0x0 .. 0x%08lx)\n",
	     memsize, CPU.msize - 1);

  /* Clean out the GPRs */
  for (i = 0; i < 32; i++)
    CPU.regs[i] = 0;
  CPU.insts = 0;
  CPU.cycles = 0;
  CPU.imm_enable = 0;
}

#define WATCHFUNCTIONS 1
#ifdef WATCHFUNCTIONS

#define MAXWL 80
word WL[MAXWL];
char *WLstr[MAXWL];

int ENDWL=0;
int WLincyc;
int WLcyc[MAXWL];
int WLcnts[MAXWL];
int WLmax[MAXWL];
int WLmin[MAXWL];
word WLendpc;
int WLbcyc;
int WLW;
#endif

static int tracing = 0;

void
sim_resume (SIM_DESC sd, int step, int siggnal)
{
  int needfetch;
  word inst;
  enum microblaze_instr op;
  int memops;
  int bonus_cycles;
  int insts;
  int w;
  int cycs;
  word WLhash;
  ubyte carry;
  int imm_unsigned;
  short ra, rb, rd;
  long immword;
  uword oldpc, newpc;
  short delay_slot_enable;
  short branch_taken;
  short num_delay_slot; /* UNUSED except as reqd parameter */
  enum microblaze_instr_type insn_type;

  CPU.exception = step ? SIGTRAP : 0;

  memops = 0;
  bonus_cycles = 0;
  insts = 0;

  do
    {
      /* Fetch the initial instructions that we'll decode. */
      inst = rlat (PC & 0xFFFFFFFC);

      op = get_insn_microblaze (inst, &imm_unsigned, &insn_type,
				&num_delay_slot);

      if (op == invalid_inst)
	fprintf (stderr, "Unknown instruction 0x%04x", inst);

      if (tracing)
	fprintf (stderr, "%.4x: inst = %.4x ", PC, inst);

      rd = GET_RD;
      rb = GET_RB;
      ra = GET_RA;
      /*      immword = IMM_W; */

      oldpc = PC;
      delay_slot_enable = 0;
      branch_taken = 0;
      if (op == microblaze_brk)
	CPU.exception = SIGTRAP;
      else if (inst == MICROBLAZE_HALT_INST)
	{
	  CPU.exception = SIGQUIT;
	  insts += 1;
	  bonus_cycles++;
	}
      else
	{
	  switch(op)
	    {
#define INSTRUCTION(NAME, OPCODE, TYPE, ACTION)		\
	    case NAME:					\
	      ACTION;					\
	      break;
#include "microblaze.isa"
#undef INSTRUCTION

	    default:
	      CPU.exception = SIGILL;
	      fprintf (stderr, "ERROR: Unknown opcode\n");
	    }
	  /* Make R0 consistent */
	  CPU.regs[0] = 0;

	  /* Check for imm instr */
	  if (op == imm)
	    IMM_ENABLE = 1;
	  else
	    IMM_ENABLE = 0;

	  /* Update cycle counts */
	  insts ++;
	  if (insn_type == memory_store_inst || insn_type == memory_load_inst)
	    memops++;
	  if (insn_type == mult_inst)
	    bonus_cycles++;
	  if (insn_type == barrel_shift_inst)
	    bonus_cycles++;
	  if (insn_type == anyware_inst)
	    bonus_cycles++;
	  if (insn_type == div_inst)
	    bonus_cycles += 33;

	  if ((insn_type == branch_inst || insn_type == return_inst)
	      && branch_taken)
	    {
	      /* Add an extra cycle for taken branches */
	      bonus_cycles++;
	      /* For branch instructions handle the instruction in the delay slot */
	      if (delay_slot_enable)
	        {
	          newpc = PC;
	          PC = oldpc + INST_SIZE;
	          inst = rlat (PC & 0xFFFFFFFC);
	          op = get_insn_microblaze (inst, &imm_unsigned, &insn_type,
					    &num_delay_slot);
	          if (op == invalid_inst)
		    fprintf (stderr, "Unknown instruction 0x%04x", inst);
	          if (tracing)
		    fprintf (stderr, "%.4x: inst = %.4x ", PC, inst);
	          rd = GET_RD;
	          rb = GET_RB;
	          ra = GET_RA;
	          /*	      immword = IMM_W; */
	          if (op == microblaze_brk)
		    {
		      if (issue_messages)
		        fprintf (stderr, "Breakpoint set in delay slot "
			         "(at address 0x%x) will not be honored\n", PC);
		      /* ignore the breakpoint */
		    }
	          else if (insn_type == branch_inst || insn_type == return_inst)
		    {
		      if (issue_messages)
		        fprintf (stderr, "Cannot have branch or return instructions "
			         "in delay slot (at address 0x%x)\n", PC);
		      CPU.exception = SIGILL;
		    }
	          else
		    {
		      switch(op)
		        {
#define INSTRUCTION(NAME, OPCODE, TYPE, ACTION)		\
		        case NAME:			\
			  ACTION;			\
			  break;
#include "microblaze.isa"
#undef INSTRUCTION

		        default:
		          CPU.exception = SIGILL;
		          fprintf (stderr, "ERROR: Unknown opcode at 0x%x\n", PC);
		        }
		      /* Update cycle counts */
		      insts++;
		      if (insn_type == memory_store_inst
		          || insn_type == memory_load_inst)
		        memops++;
		      if (insn_type == mult_inst)
		        bonus_cycles++;
		      if (insn_type == barrel_shift_inst)
		        bonus_cycles++;
		      if (insn_type == anyware_inst)
		        bonus_cycles++;
		      if (insn_type == div_inst)
		        bonus_cycles += 33;
		    }
	          /* Restore the PC */
	          PC = newpc;
	          /* Make R0 consistent */
	          CPU.regs[0] = 0;
	          /* Check for imm instr */
	          if (op == imm)
		    IMM_ENABLE = 1;
	          else
		    IMM_ENABLE = 0;
	        }
	      else
		/* no delay slot: increment cycle count */
		bonus_cycles++;
	    }
	}

      if (tracing)
	fprintf (stderr, "\n");
    }
  while (!CPU.exception);

  /* Hide away the things we've cached while executing.  */
  /*  CPU.pc = pc; */
  CPU.insts += insts;		/* instructions done ... */
  CPU.cycles += insts;		/* and each takes a cycle */
  CPU.cycles += bonus_cycles;	/* and extra cycles for branches */
  CPU.cycles += memops; 	/* and memop cycle delays */
}


int
sim_write (SIM_DESC sd, SIM_ADDR addr, const unsigned char *buffer, int size)
{
  int i;
  init_pointers ();

  memcpy (&CPU.memory[addr], buffer, size);

  return size;
}

int
sim_read (SIM_DESC sd, SIM_ADDR addr, unsigned char *buffer, int size)
{
  int i;
  init_pointers ();

  memcpy (buffer, &CPU.memory[addr], size);

  return size;
}


int
sim_store_register (SIM_DESC sd, int rn, unsigned char *memory, int length)
{
  init_pointers ();

  if (rn < NUM_REGS + NUM_SPECIAL && rn >= 0)
    {
      if (length == 4)
	{
	  /* misalignment safe */
	  long ival = microblaze_extract_unsigned_integer (memory, 4);
	  if (rn < NUM_REGS)
	    CPU.regs[rn] = ival;
	  else
	    CPU.spregs[rn-NUM_REGS] = ival;
	  return 4;
	}
      else
	return 0;
    }
  else
    return 0;
}

int
sim_fetch_register (SIM_DESC sd, int rn, unsigned char *memory, int length)
{
  long ival;
  init_pointers ();

  if (rn < NUM_REGS + NUM_SPECIAL && rn >= 0)
    {
      if (length == 4)
	{
	  if (rn < NUM_REGS)
	    ival = CPU.regs[rn];
	  else
	    ival = CPU.spregs[rn-NUM_REGS];

	  /* misalignment-safe */
	  microblaze_store_unsigned_integer (memory, 4, ival);
	  return 4;
	}
      else
	return 0;
    }
  else
    return 0;
}


int
sim_trace (SIM_DESC sd)
{
  tracing = 1;

  sim_resume (sd, 0, 0);

  tracing = 0;

  return 1;
}

void
sim_stop_reason (SIM_DESC sd, enum sim_stop *reason, int *sigrc)
{
  if (CPU.exception == SIGQUIT)
    {
      *reason = sim_exited;
      *sigrc = RETREG;
    }
  else
    {
      *reason = sim_stopped;
      *sigrc = CPU.exception;
    }
}


int
sim_stop (SIM_DESC sd)
{
  CPU.exception = SIGINT;
  return 1;
}


void
sim_info (SIM_DESC sd, int verbose)
{
#ifdef WATCHFUNCTIONS
  int w, wcyc;
#endif

  callback->printf_filtered (callback, "\n\n# instructions executed  %10d\n",
			     CPU.insts);
  callback->printf_filtered (callback, "# cycles                 %10d\n",
			     (CPU.cycles) ? CPU.cycles+2 : 0);

#ifdef WATCHFUNCTIONS
  callback->printf_filtered (callback, "\nNumber of watched functions: %d\n",
			     ENDWL);

  wcyc = 0;

  for (w = 1; w <= ENDWL; w++)
    {
      callback->printf_filtered (callback, "WL = %s %8x\n",WLstr[w],WL[w]);
      callback->printf_filtered (callback, "  calls = %d, cycles = %d\n",
				 WLcnts[w],WLcyc[w]);

      if (WLcnts[w] != 0)
	callback->printf_filtered (callback,
				   "  maxcpc = %d, mincpc = %d, avecpc = %d\n",
				   WLmax[w],WLmin[w],WLcyc[w]/WLcnts[w]);
      wcyc += WLcyc[w];
    }

  callback->printf_filtered (callback,
			     "Total cycles for watched functions: %d\n",wcyc);
#endif
}

struct	aout
{
  unsigned char  sa_machtype[2];
  unsigned char  sa_magic[2];
  unsigned char  sa_tsize[4];
  unsigned char  sa_dsize[4];
  unsigned char  sa_bsize[4];
  unsigned char  sa_syms[4];
  unsigned char  sa_entry[4];
  unsigned char  sa_trelo[4];
  unsigned char  sa_drelo[4];
} aout;

#define	LONG(x)		(((x)[0]<<24)|((x)[1]<<16)|((x)[2]<<8)|(x)[3])
#define	SHORT(x)	(((x)[0]<<8)|(x)[1])

SIM_DESC
sim_open (SIM_OPEN_KIND kind, host_callback *cb, struct bfd *abfd, char **argv)
{
  /*  SIM_DESC sd = sim_state_alloc(kind, alloc);*/

  int osize = sim_memory_size;
  myname = argv[0];
  callback = cb;

  if (kind == SIM_OPEN_STANDALONE)
    issue_messages = 1;

  /* Discard and reacquire memory -- start with a clean slate.  */
  sim_size (1);		/* small */
  sim_size (osize);	/* and back again */

  set_initial_gprs ();	/* Reset the GPR registers.  */

  return ((SIM_DESC) 1);
}

void
sim_close (SIM_DESC sd, int quitting)
{
  if (CPU.memory)
    {
      free(CPU.memory);
      CPU.memory = NULL;
      CPU.msize = 0;
    }
}

SIM_RC
sim_load (SIM_DESC sd, const char *prog, bfd *abfd, int from_tty)
{
  /* Do the right thing for ELF executables; this turns out to be
     just about the right thing for any object format that:
       - we crack using BFD routines
       - follows the traditional UNIX text/data/bss layout
       - calls the bss section ".bss".   */

  extern bfd *sim_load_file (); /* ??? Don't know where this should live.  */
  bfd *prog_bfd;

  {
    bfd *handle;
    asection *s;
    int found_loadable_section = 0;
    bfd_vma max_addr = 0;
    handle = bfd_openr (prog, 0);

    if (!handle)
      {
	printf("``%s'' could not be opened.\n", prog);
	return SIM_RC_FAIL;
      }

    /* Makes sure that we have an object file, also cleans gets the
       section headers in place.  */
    if (!bfd_check_format (handle, bfd_object))
      {
	/* wasn't an object file */
	bfd_close (handle);
	printf ("``%s'' is not appropriate object file.\n", prog);
	return SIM_RC_FAIL;
      }

    for (s = handle->sections; s; s = s->next)
      {
	if (s->flags & SEC_ALLOC)
	  {
	    bfd_vma vma = 0;
	    int size = bfd_get_section_size (s);
	    if (size > 0)
	      {
		vma = bfd_section_vma (handle, s);
		if (vma >= max_addr)
		  {
		    max_addr = vma + size;
		  }
	      }
	    if (s->flags & SEC_LOAD)
	      found_loadable_section = 1;
	  }
      }

    if (!found_loadable_section)
      {
	/* No loadable sections */
	bfd_close(handle);
	printf("No loadable sections in file %s\n", prog);
	return SIM_RC_FAIL;
      }

    sim_memory_size = (unsigned long) max_addr;

    /* Clean up after ourselves.  */
    bfd_close (handle);

  }

  /* from sh -- dac */
  prog_bfd = sim_load_file (sd, myname, callback, prog, abfd,
			    /* sim_kind == SIM_OPEN_DEBUG, */
			    0,
			    0, sim_write);
  if (prog_bfd == NULL)
    return SIM_RC_FAIL;

  target_big_endian = bfd_big_endian (prog_bfd);
  PC = bfd_get_start_address (prog_bfd);

  if (abfd == NULL)
    bfd_close (prog_bfd);

  return SIM_RC_OK;
}

SIM_RC
sim_create_inferior (SIM_DESC sd, struct bfd *prog_bfd, char **argv, char **env)
{
  char **avp;
  int nargs = 0;
  int nenv = 0;
  int s_length;
  int l;
  unsigned long strings;
  unsigned long pointers;
  unsigned long hi_stack;


  /* Set the initial register set.  */
  l = issue_messages;
  issue_messages = 0;
  set_initial_gprs ();
  issue_messages = l;

  hi_stack = CPU.msize - 4;
  PC = bfd_get_start_address (prog_bfd);

  /* For now ignore all parameters to the program */

  return SIM_RC_OK;
}

void
sim_do_command (SIM_DESC sd, const char *cmd)
{
  /* Nothing there yet; it's all an error.  */

  if (cmd != NULL)
    {
      char ** simargv = buildargv (cmd);

      if (strcmp (simargv[0], "watch") == 0)
	{
	  if ((simargv[1] == NULL) || (simargv[2] == NULL))
	    {
	      fprintf (stderr, "Error: missing argument to watch cmd.\n");
	      freeargv (simargv);
	      return;
	    }

	  ENDWL++;

	  WL[ENDWL] = strtol (simargv[2], NULL, 0);
	  WLstr[ENDWL] = strdup (simargv[1]);
	  fprintf (stderr, "Added %s (%x) to watchlist, #%d\n",WLstr[ENDWL],
		   WL[ENDWL], ENDWL);

	}
      else if (strcmp (simargv[0], "dumpmem") == 0)
	{
	  unsigned char * p;
	  FILE * dumpfile;

	  if (simargv[1] == NULL)
	    fprintf (stderr, "Error: missing argument to dumpmem cmd.\n");

	  fprintf (stderr, "Writing dumpfile %s...",simargv[1]);

	  dumpfile = fopen (simargv[1], "w");
	  p = CPU.memory;
	  fwrite (p, CPU.msize-1, 1, dumpfile);
	  fclose (dumpfile);

	  fprintf (stderr, "done.\n");
	}
      else if (strcmp (simargv[0], "clearstats") == 0)
	{
	  CPU.cycles = 0;
	  CPU.insts = 0;
	  ENDWL = 0;
	}
      else if (strcmp (simargv[0], "verbose") == 0)
	{
	  issue_messages = 2;
	}
      else
	{
	  fprintf (stderr,"Error: \"%s\" is not a valid M.CORE simulator command.\n",
		   cmd);
	}

      freeargv (simargv);
    }
  else
    {
      fprintf (stderr, "M.CORE sim commands: \n");
      fprintf (stderr, "  watch <funcname> <addr>\n");
      fprintf (stderr, "  dumpmem <filename>\n");
      fprintf (stderr, "  clearstats\n");
      fprintf (stderr, "  verbose\n");
    }
}

void
sim_set_callbacks (host_callback *ptr)
{
  callback = ptr;
}

char **
sim_complete_command (SIM_DESC sd, const char *text, const char *word)
{
  return NULL;
}