/* -*-c-*- ------------------ mix_vm.c :
 * Implementation of the functions declared in mix_vm.h
 * ------------------------------------------------------------------
 * Copyright (C) 2000 jose antonio ortega ruiz <jaortega@acm.org>
 *  
 * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *  
 */

#include "mix.h"
#include "xmix_vm.h"

static void
vm_reset_ (mix_vm_t *vm)
{
  guint k;
  set_rA_ (vm, MIX_WORD_ZERO);
  set_rX_ (vm, MIX_WORD_ZERO);
  set_rJ_ (vm, MIX_WORD_ZERO);
  for ( k = 1; k < IREG_NO_+1; ++k )
    set_rI_ (vm, k, MIX_WORD_ZERO);
  set_over_ (vm, FALSE);
  set_cmp_ (vm, mix_EQ);
  set_loc_ (vm, MIX_WORD_ZERO);
  for ( k = 0; k < MEM_CELLS_NO_; ++k)
    set_cell_ (vm, k, MIX_WORD_ZERO);
  halt_ (vm, FALSE);
  if (vm->symbol_table != NULL )
    {
      mix_symbol_table_delete (vm->symbol_table);
      vm->symbol_table = NULL;
    }
  if (vm->line_table != NULL)
    {
      g_tree_destroy (vm->line_table);
      vm->line_table = NULL;
    }
  if (vm->address_table != NULL)
    {
      g_tree_destroy (vm->address_table);
      vm->address_table = NULL;
    }
  if (vm->src_file != NULL)
    {
      mix_src_file_delete (vm->src_file);
      vm->src_file = NULL;
    }
  bp_clear_all_ (vm);
}


/* Create/destroy a mix vm */
mix_vm_t *
mix_vm_new (void)
{
  int i;
  
  mix_vm_t *vm = g_new (struct mix_vm_t,1);
  vm->line_table = NULL;
  vm->address_table = NULL;
  vm->symbol_table = NULL;
  
  for (i = 0; i < BD_NO_; ++i)
    vm->devices[i] = NULL;
  
  vm->clock = mix_vm_clock_new ();
  
  vm_reset_ (vm);
  return vm;
}


void
mix_vm_delete (mix_vm_t * vm)
{
  int i;
  
  if (vm->line_table != NULL) g_tree_destroy (vm->line_table);
  if (vm->address_table != NULL) g_tree_destroy (vm->address_table);
  if (vm->symbol_table != NULL) mix_symbol_table_delete (vm->symbol_table);
  if (vm->src_file != NULL) mix_src_file_delete (vm->src_file);
  for (i = 0; i < BD_NO_; ++i)
    mix_device_delete (vm->devices[i]);
  mix_vm_clock_delete (vm->clock);
  g_free (vm);
}

/* Reset a vm  (set state as of a newly created one) */
void
mix_vm_reset (mix_vm_t * vm)
{
  g_return_if_fail (vm != NULL);
  vm_reset_ (vm);
}

/* Set start address for execution */
void
mix_vm_set_start_addr (mix_vm_t *vm, mix_address_t addr)
{
  g_return_if_fail (vm != NULL);
  set_loc_ (vm, addr);
}

/* Access to the vm's registers */
mix_word_t
mix_vm_get_rA (const mix_vm_t *vm)
{
  g_return_val_if_fail (vm != NULL, MIX_WORD_ZERO);
  return get_rA_ (vm);
}

mix_word_t
mix_vm_get_rX (const mix_vm_t *vm)
{
  g_return_val_if_fail (vm != NULL, MIX_WORD_ZERO);
  return get_rX_ (vm);
}

mix_short_t
mix_vm_get_rJ (const mix_vm_t *vm)
{
  g_return_val_if_fail (vm != NULL, MIX_SHORT_ZERO);
  return mix_word_to_short_fast (get_rJ_ (vm));
}

mix_short_t
mix_vm_get_rI (const mix_vm_t *vm, guint idx)
{
  g_return_val_if_fail (vm != NULL, MIX_SHORT_ZERO);
  g_return_val_if_fail (IOK_ (idx), MIX_SHORT_ZERO);
  return mix_word_to_short_fast (get_rI_ (vm, idx));
}

void 
mix_vm_set_rA (mix_vm_t *vm, mix_word_t value)
{
  g_return_if_fail (vm != NULL);
  set_rA_ (vm, value);
}

void
mix_vm_set_rX (mix_vm_t *vm, mix_word_t value)
{
  g_return_if_fail (vm != NULL);
  set_rX_ (vm, value);
}

void 
mix_vm_set_rJ (mix_vm_t *vm, mix_short_t value)
{
  g_return_if_fail (vm != NULL);
  g_return_if_fail (mix_short_is_positive (value));
  set_rJ_ (vm, mix_short_to_word_fast (value));
}

void 
mix_vm_set_rI (mix_vm_t *vm, guint idx, mix_short_t value)
{
  g_return_if_fail (vm != NULL);
  g_return_if_fail (IOK_ (idx));
  set_rI_ (vm, idx, mix_short_to_word_fast (value));
}

/* Access to the comparison flag and overflow toggle */
mix_cmpflag_t
mix_vm_get_cmpflag (const mix_vm_t *vm)
{
  g_return_val_if_fail (vm != NULL, mix_EQ);
  return get_cmp_ (vm);
}

void
mix_vm_set_cmpflag (mix_vm_t *vm, mix_cmpflag_t value)
{
  g_return_if_fail (vm != NULL);
  set_cmp_ (vm, value);
}

gboolean
mix_vm_get_overflow (const mix_vm_t *vm)
{
  g_return_val_if_fail (vm != NULL, TRUE);
  return get_over_ (vm);
}

void
mix_vm_set_overflow (mix_vm_t *vm, gboolean value)
{
  g_return_if_fail (vm != NULL);
  set_over_ (vm, value);
}

void
mix_vm_toggle_overflow (mix_vm_t *vm)
{
  g_return_if_fail (vm != NULL);
  set_over_ (vm, !get_over_ (vm));
}

/* Access to memory cells */
mix_word_t
mix_vm_get_addr_contents (const mix_vm_t *vm, mix_address_t addr)
{
  g_return_val_if_fail (vm != NULL, MIX_WORD_ZERO);
  g_return_val_if_fail (MEMOK_ (addr), MIX_WORD_ZERO);
  return get_cell_ (vm, addr);
}

void
mix_vm_set_addr_contents (mix_vm_t *vm, mix_address_t addr, mix_word_t value)
{
  g_return_if_fail (vm != NULL);
  g_return_if_fail (MEMOK_ (addr));
  set_cell_ (vm, addr, value);
}

gboolean
mix_vm_is_halted (const mix_vm_t *vm)
{
  return is_halted_ (vm);
}

/* Execution of instructions */
gboolean /* TRUE if success */
mix_vm_exec_ins (mix_vm_t *vm, const mix_ins_t *ins)
{
  g_return_val_if_fail (vm != NULL, FALSE);
  g_return_val_if_fail (ins != NULL, FALSE);
  return (*ins_handlers_[ins->opcode]) (vm,ins);
}

/* comparison function for the line and address tables tree */
static gint
cmp_uint_ (gconstpointer a, gconstpointer b)
{
  return GPOINTER_TO_UINT (a) - GPOINTER_TO_UINT (b);
}

gboolean
mix_vm_load_file (mix_vm_t *vm, const gchar *name)
{
  mix_code_file_t *file;
  mix_ins_desc_t ins;
  const gchar *sp;
  
  g_return_val_if_fail (vm != NULL, FALSE);
  file = mix_code_file_new_read (name);
  if (file == NULL) return FALSE;
  vm_reset_ (vm);
  if ( mix_code_file_is_debug (file) )
    {
      vm->symbol_table = mix_code_file_get_symbol_table (file);
      vm->line_table = g_tree_new (cmp_uint_);
      vm->address_table = g_tree_new (cmp_uint_);
    }

  sp = mix_code_file_get_source_path (file);
  if (sp != NULL)
    vm->src_file = mix_src_file_new_for_read (sp);
  
  while ( mix_code_file_get_ins (file, &ins) ) 
    {
      set_cell_ (vm, ins.address, ins.ins);
      if ( vm->line_table != NULL )
	{
	  g_tree_insert (vm->line_table, 
			 GUINT_TO_POINTER (ins.lineno),
			 GUINT_TO_POINTER ((guint)ins.address));
	  g_tree_insert (vm->address_table, 
			 GUINT_TO_POINTER ((guint)ins.address),
			 GUINT_TO_POINTER (ins.lineno));
	}
    }
  set_loc_ (vm, mix_code_file_get_start_addr (file));
  set_start_ (vm, get_loc_ (vm));
  mix_code_file_delete (file);
  
  return TRUE;
}

const mix_src_file_t *
mix_vm_get_src_file (const mix_vm_t *vm)
{
  g_return_val_if_fail (vm != NULL, NULL);
  return vm->src_file;
}

const mix_symbol_table_t *
mix_vm_get_symbol_table (const mix_vm_t *vm)
{
  g_return_val_if_fail (vm != NULL, NULL);
  return vm->symbol_table;
}

mix_address_t 
mix_vm_get_prog_count (const mix_vm_t *vm)
{
  g_return_val_if_fail (vm != NULL, MIX_SHORT_ZERO);
  return get_loc_ (vm);
}

/* Reposition program counter and reset state so that a loaded
   program can be restarted.
*/
void
mix_vm_reset_program (mix_vm_t *vm)
{
  guint k;
  g_return_if_fail (vm != NULL);
  reset_loc_ (vm);
  halt_ (vm, FALSE);
  set_rA_ (vm, MIX_WORD_ZERO);
  set_rX_ (vm, MIX_WORD_ZERO);
  set_rJ_ (vm, MIX_WORD_ZERO);
  for ( k = 1; k < IREG_NO_+1; ++k )
    set_rI_ (vm, k, MIX_WORD_ZERO);
  set_over_ (vm, FALSE);
  set_cmp_ (vm, mix_EQ);
}

/* continue execution of instructions in memory */
int
mix_vm_run (mix_vm_t *vm)
{
  mix_ins_t ins;
  g_return_val_if_fail (vm != NULL, MIX_VM_ERROR);
  
  while ( !is_halted_ (vm) )
    {
      mix_word_to_ins_uncheck (get_cell_ (vm, get_loc_ (vm)), ins);
      if ( !(*ins_handlers_[ins.opcode]) (vm,&ins) ) 
	return MIX_VM_ERROR;
      else
	update_time_ (vm, &ins);
      if (bp_is_set_ (vm, get_loc_ (vm)))
	return MIX_VM_BREAK;
      if (get_loc_ (vm) >= MIX_VM_CELL_NO) halt_ (vm, TRUE);
    }
  return MIX_VM_HALT;
}

/* execute next memory instruction */
int
mix_vm_exec_next (mix_vm_t *vm)
{
  mix_ins_t ins;
  g_return_val_if_fail (vm != NULL, MIX_VM_ERROR);
  if (get_loc_ (vm) >= MIX_VM_CELL_NO) halt_ (vm, TRUE);
  if (is_halted_ (vm)) return MIX_VM_HALT;
  mix_word_to_ins_uncheck (get_cell_ (vm, get_loc_ (vm)), ins);
  if (!(*ins_handlers_[ins.opcode]) (vm, &ins))
    return MIX_VM_ERROR;
  else
    update_time_ (vm, &ins);
  if (is_halted_ (vm)) return MIX_VM_HALT;
  return bp_is_set_ (vm, get_loc_ (vm)) ? MIX_VM_BREAK : MIX_VM_OK;
}

/* Breakpoints */
gulong
mix_vm_get_break_lineno (const mix_vm_t *vm)
{
  g_return_val_if_fail (vm != NULL, 0);
  if (vm->address_table == NULL)
    return 0;
  else
    {
      gpointer loc = GUINT_TO_POINTER ((guint)get_loc_ (vm));
      return GPOINTER_TO_UINT (g_tree_lookup (vm->address_table,loc));
    }
}

typedef struct 
{
  mix_vm_t *vm;
  guint lineno;
  gint result;
} bp_traverse_t;

static gint
set_break_ (gpointer key, gpointer value, gpointer data)
{
  bp_traverse_t *tr = (bp_traverse_t *)data;
  if (GPOINTER_TO_UINT (key) >= tr->lineno)
    {
      bp_set_ (tr->vm, mix_short_new (GPOINTER_TO_UINT (value)));
      tr->lineno = GPOINTER_TO_UINT (key);
      tr->result = MIX_VM_BP_OK;
      return TRUE;
    }
  return FALSE;
}

gint /* if >0 the line no. of the break point */
mix_vm_set_breakpoint (mix_vm_t *vm, guint lineno)
{
  bp_traverse_t tr;
  
  g_return_val_if_fail (vm != NULL, MIX_VM_BP_ERROR);
  if (!vm->line_table) return MIX_VM_BP_NDEBUG;
  tr.lineno = lineno;
  tr.vm = vm;
  tr.result = MIX_VM_BP_INV_LINE;
  g_tree_traverse (vm->line_table, set_break_, G_IN_ORDER, (gpointer)&tr);
  if (tr.result == MIX_VM_BP_OK)
    return tr.lineno;
  else
    return tr.result;
}

gint
mix_vm_set_breakpoint_address (mix_vm_t *vm, guint address) 
{
  g_return_val_if_fail (vm != NULL, MIX_VM_BP_ERROR);
  if (address >= MIX_VM_CELL_NO)
    return MIX_VM_BP_INV_ADDRESS;
  else
    bp_set_ (vm, mix_short_new (address));
  return MIX_VM_BP_OK;
}

static gint
clear_break_ (gpointer key, gpointer value, gpointer data)
{
  bp_traverse_t *tr = (bp_traverse_t *)data;
  if (GPOINTER_TO_UINT (key) == tr->lineno)
    {
      bp_clear_ (tr->vm, mix_short_new (GPOINTER_TO_UINT (value)));
      tr->result = MIX_VM_BP_OK;
      return TRUE;
    }
  else if (GPOINTER_TO_UINT (key) > tr->lineno)
    return TRUE;
  
  return FALSE;
}

gint /* one of MIX_VM_BP_ */
mix_vm_clear_breakpoint (mix_vm_t *vm, guint lineno)
{
  bp_traverse_t tr;
  
  g_return_val_if_fail (vm != NULL, MIX_VM_BP_ERROR);
  if (!vm->line_table) return MIX_VM_BP_NDEBUG;
  tr.lineno = lineno;
  tr.vm = vm;
  tr.result = MIX_VM_BP_INV_LINE;
  g_tree_traverse (vm->line_table, clear_break_, G_IN_ORDER, (gpointer)&tr);
  return tr.result;
}

gint
mix_vm_clear_breakpoint_address (mix_vm_t *vm, guint address) 
{
  g_return_val_if_fail (vm != NULL, MIX_VM_BP_ERROR);
  if (address >= MIX_VM_CELL_NO)
    return MIX_VM_BP_INV_ADDRESS;
  else
    bp_clear_ (vm, mix_short_new (address));
  return MIX_VM_BP_OK;
}

void
mix_vm_clear_all_breakpoints (mix_vm_t *vm)
{
  g_return_if_fail (vm != NULL);
  bp_clear_all_ (vm);
}

/* Get the vm uptime, defined as the time spent executing instructions */
mix_time_t
mix_vm_get_uptime (const mix_vm_t *vm)
{
  g_return_val_if_fail (vm != NULL, 0);
  return mix_vm_clock_get_time (get_clock_ (vm));
}