correct error tracking and reporting.

2 files changed, 105 insertions, 51 deletions

diff --git a/mixlib/mix_vm.c b/mixlib/mix_vm.c
index 4bbc976..8e8a065 100644
--- a/mixlib/mix_vm.c
+++ b/mixlib/mix_vm.c
@@ -1,22 +1,22 @@
 /* -*-c-*- ------------------ mix_vm.c :
  * Implementation of the functions declared in mix_vm.h
  * ------------------------------------------------------------------
- * Copyright (C) 2000, 2001 Free Software Foundation, Inc.
- *  
+ * Copyright (C) 2000, 2001, 2004 Free Software Foundation, Inc.
+ *
  * 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"
@@ -37,6 +37,7 @@ vm_reset_reload_ (mix_vm_t *vm, gboolean is_reload)
   set_over_ (vm, FALSE);
   set_cmp_ (vm, mix_EQ);
   set_loc_ (vm, MIX_WORD_ZERO);
+  set_last_error_ (vm, MIX_VM_ERROR_NONE);
   for ( k = 0; k < MEM_CELLS_NO_; ++k)
     set_cell_ (vm, k, MIX_WORD_ZERO);
   if (vm->symbol_table != NULL )
@@ -81,7 +82,7 @@ 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;
@@ -89,13 +90,14 @@ mix_vm_new (void)
   vm->src_file = NULL;
   vm->pred_list = mix_predicate_list_new (vm);
   vm->address_list = NULL;
-  
+  vm->last_error = MIX_VM_ERROR_NONE;
+
   for (i = 0; i < BD_NO_; ++i)
     vm->devices[i] = NULL;
-  
+
   vm->clock = mix_vm_clock_new ();
   vm->factory = mix_device_new;
-  
+
   vm_reset_ (vm);
 
   return vm;
@@ -106,9 +108,9 @@ void
 mix_vm_delete (mix_vm_t * vm)
 {
   int i;
-  
+
   g_return_if_fail (vm != NULL);
-  
+
   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);
@@ -127,14 +129,14 @@ mix_vm_connect_device (mix_vm_t *vm, mix_device_t *device)
 {
   mix_device_t *old;
   mix_device_type_t type;
-  
+
   g_return_val_if_fail (vm != NULL, NULL);
   g_return_val_if_fail (device != NULL, NULL);
-  
+
   type = mix_device_type (device);
   old = vm->devices[type];
   vm->devices[type] = device;
-  
+
   return old;
 }
 
@@ -202,7 +204,7 @@ mix_vm_get_rI (const mix_vm_t *vm, guint idx)
   return mix_word_to_short_fast (get_rI_ (vm, idx));
 }
 
-void 
+void
 mix_vm_set_rA (mix_vm_t *vm, mix_word_t value)
 {
   g_return_if_fail (vm != NULL);
@@ -216,7 +218,7 @@ mix_vm_set_rX (mix_vm_t *vm, mix_word_t value)
   set_rX_ (vm, value);
 }
 
-void 
+void
 mix_vm_set_rJ (mix_vm_t *vm, mix_short_t value)
 {
   g_return_if_fail (vm != NULL);
@@ -224,7 +226,7 @@ mix_vm_set_rJ (mix_vm_t *vm, mix_short_t value)
   set_rJ_ (vm, mix_short_to_word_fast (value));
 }
 
-void 
+void
 mix_vm_set_rI (mix_vm_t *vm, guint idx, mix_short_t value)
 {
   g_return_if_fail (vm != NULL);
@@ -273,16 +275,14 @@ 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);
+  return (MEMOK_ (addr))? get_cell_ (vm, addr) : MIX_WORD_ZERO;
 }
 
 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);
+  if (MEMOK_ (addr)) set_cell_ (vm, addr, value);
 }
 
 gboolean
@@ -315,7 +315,7 @@ mix_vm_load_file (mix_vm_t *vm, const gchar *name)
   mix_ins_desc_t ins;
   const gchar *sp;
   gboolean reload = FALSE;
-  
+
   g_return_val_if_fail (vm != NULL, FALSE);
   file = mix_code_file_new_read (name);
   if (file == NULL)
@@ -343,16 +343,16 @@ mix_vm_load_file (mix_vm_t *vm, const gchar *name)
     }
 
   vm->src_file = sfile;
-  
-  while ( mix_code_file_get_ins (file, &ins) ) 
+
+  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, 
+	  g_tree_insert (vm->line_table,
 			 GUINT_TO_POINTER (ins.lineno),
 			 GUINT_TO_POINTER ((guint)ins.address));
-	  g_tree_insert (vm->address_table, 
+	  g_tree_insert (vm->address_table,
 			 GUINT_TO_POINTER ((guint)ins.address),
 			 GUINT_TO_POINTER (ins.lineno));
 	}
@@ -360,7 +360,7 @@ mix_vm_load_file (mix_vm_t *vm, const gchar *name)
   set_loc_ (vm, mix_code_file_get_start_addr (file));
   set_start_ (vm, get_loc_ (vm));
   mix_code_file_delete (file);
-  
+
   set_status_ (vm, MIX_VM_LOADED);
   return TRUE;
 }
@@ -379,7 +379,7 @@ mix_vm_get_symbol_table (const mix_vm_t *vm)
   return vm->symbol_table;
 }
 
-mix_address_t 
+mix_address_t
 mix_vm_get_prog_count (const mix_vm_t *vm)
 {
   g_return_val_if_fail (vm != NULL, MIX_SHORT_ZERO);
@@ -394,13 +394,13 @@ mix_vm_get_address_lineno (const mix_vm_t *vm, mix_address_t addr)
   guint lineno;
 
   g_return_val_if_fail (vm != NULL, 0);
-  g_return_val_if_fail (MEMOK_ (addr), 0);
+  if (!(MEMOK_ (addr))) return 0;
   lineno = GPOINTER_TO_UINT (g_tree_lookup (vm->address_table, gp_addr));
   return lineno;
 }
 
 /* Get the address for a given source line number */
-typedef struct 
+typedef struct
 {
   guint lineno;
   mix_address_t result;
@@ -422,7 +422,7 @@ mix_address_t
 mix_vm_get_lineno_address (const mix_vm_t *vm, guint lineno)
 {
   addr_traverse_t tr;
-  
+
   g_return_val_if_fail (vm != NULL, MIX_VM_CELL_NO);
   if (!vm->line_table) return MIX_VM_CELL_NO;
   tr.lineno = lineno;
@@ -438,14 +438,14 @@ 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);
       vm->address_list =
 	g_slist_prepend (vm->address_list,
 			 GINT_TO_POINTER ((gint)get_loc_ (vm)));
-      if ( !(*ins_handlers_[ins.opcode]) (vm,&ins) ) 
+      if ( !(*ins_handlers_[ins.opcode]) (vm,&ins) )
 	return set_status_ (vm, MIX_VM_ERROR);
       else
 	update_time_ (vm, &ins);
@@ -489,6 +489,39 @@ mix_vm_get_run_status (const mix_vm_t *vm)
   return get_status_ (vm);
 }
 
+mix_vm_error_t
+mix_vm_get_last_error (const mix_vm_t *vm)
+{
+  g_return_val_if_fail (vm != NULL, MIX_VM_ERROR_UNEXPECTED);
+  return get_last_error_ (vm);
+}
+
+const gchar *
+mix_vm_get_last_error_string (const mix_vm_t *vm)
+{
+  return mix_vm_get_error_string (mix_vm_get_last_error (vm));
+}
+
+const gchar *
+mix_vm_get_error_string (mix_vm_error_t code)
+{
+  static const gchar *errors[] = {
+    N_("No error"),
+    N_("Invalid memory address"),
+    N_("Invalid device number"),
+    N_("Invalid fspec"),
+    N_("Invalid M-value"),
+    N_("Cannot access device"),
+    N_("Cannot access device for reading"),
+    N_("Cannot access device for writing"),
+    N_("Unexpected error"),
+    N_("Unknow error code")
+  };
+
+  return errors[(code < 0 || code > MIX_VM_ERROR_UNEXPECTED)
+                ? MIX_VM_ERROR_UNEXPECTED + 1 : code];
+}
+
 /* Breakpoints */
 gulong
 mix_vm_get_break_lineno (const mix_vm_t *vm)
@@ -503,7 +536,7 @@ mix_vm_get_break_lineno (const mix_vm_t *vm)
     }
 }
 
-typedef struct 
+typedef struct
 {
   mix_vm_t *vm;
   guint lineno;
@@ -528,7 +561,7 @@ 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;
@@ -542,7 +575,7 @@ mix_vm_set_breakpoint (mix_vm_t *vm, guint lineno)
 }
 
 gint
-mix_vm_set_breakpoint_address (mix_vm_t *vm, guint address) 
+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)
@@ -572,7 +605,7 @@ clear_break_ (gpointer key, gpointer value, gpointer data)
     }
   else if (GPOINTER_TO_UINT (key) > tr->lineno)
     return TRUE;
-  
+
   return FALSE;
 }
 
@@ -580,7 +613,7 @@ 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;
@@ -591,7 +624,7 @@ mix_vm_clear_breakpoint (mix_vm_t *vm, guint lineno)
 }
 
 gint
-mix_vm_clear_breakpoint_address (mix_vm_t *vm, guint address) 
+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)
diff --git a/mixlib/mix_vm.h b/mixlib/mix_vm.h
index b7412bf..005bfc2 100644
--- a/mixlib/mix_vm.h
+++ b/mixlib/mix_vm.h
@@ -1,22 +1,22 @@
 /* ---------------------- mix_vm.h :
  * Types and functions implementing the MIX virtual machine
  * ------------------------------------------------------------------
- * Copyright (C) 2000, 2001 Free Software Foundation, Inc.
- *  
+ * Copyright (C) 2000, 2001, 2004 Free Software Foundation, Inc.
+ *
  * 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.
- *  
+ *
  */
 
 
@@ -55,7 +55,6 @@ mix_vm_connect_device (mix_vm_t *vm, mix_device_t *device);
 extern mix_device_t *
 mix_vm_get_device (const mix_vm_t *vm, mix_device_type_t dev);
 
-
 /* install a device factory for automatic connection */
 typedef mix_device_t * (* mix_device_factory_t) (mix_device_type_t device);
 extern void
@@ -82,19 +81,18 @@ mix_vm_get_rJ(const mix_vm_t *vm);
 extern mix_short_t
 mix_vm_get_rI(const mix_vm_t *vm, guint idx);
 
-extern void 
+extern void
 mix_vm_set_rA(mix_vm_t *vm, mix_word_t value);
 
 extern void
 mix_vm_set_rX(mix_vm_t *vm, mix_word_t value);
 
-extern void 
+extern void
 mix_vm_set_rJ(mix_vm_t *vm, mix_short_t value);
 
-extern void 
+extern void
 mix_vm_set_rI(mix_vm_t *vm, guint idx, mix_short_t value);
 
-
 /* Access to the comparison flag and overflow toggle */
 extern mix_cmpflag_t
 mix_vm_get_cmpflag(const mix_vm_t *vm);
@@ -125,7 +123,7 @@ mix_vm_set_addr_contents(mix_vm_t *vm, mix_address_t addr, mix_word_t value);
 extern gboolean /* TRUE if success */
 mix_vm_exec_ins(mix_vm_t *vm, const mix_ins_t *ins);
 
-/* Load a code file into memory (-name- does not need the default extension) 
+/* Load a code file into memory (-name- does not need the default extension)
  * resetting the vm's state
  */
 extern gboolean
@@ -140,7 +138,7 @@ extern const mix_symbol_table_t *
 mix_vm_get_symbol_table (const mix_vm_t *vm);
 
 /* Get current program counter */
-extern mix_address_t 
+extern mix_address_t
 mix_vm_get_prog_count (const mix_vm_t *vm);
 
 /* Get the source line number for a given address */
@@ -163,6 +161,28 @@ typedef enum {
   MIX_VM_EMPTY			/* no program loaded */
 } mix_vm_status_t;
 
+/* execution errors */
+typedef enum {
+  MIX_VM_ERROR_NONE,            /* no error */
+  MIX_VM_ERROR_BAD_ACCESS,      /* bad memory address */
+  MIX_VM_ERROR_BAD_DEVICE_NO,   /* bad device number */
+  MIX_VM_ERROR_BAD_FSPEC,       /* invalid fspec */
+  MIX_VM_ERROR_BAD_M,           /* invalid M-value */
+  MIX_VM_ERROR_DEV_CTL,         /* error accessing device for ioctl */
+  MIX_VM_ERROR_DEV_READ,        /* error accessing device for reading */
+  MIX_VM_ERROR_DEV_WRITE,       /* error accessing device for writing */
+  MIX_VM_ERROR_UNEXPECTED       /* unexpected error */
+} mix_vm_error_t;
+
+extern mix_vm_error_t
+mix_vm_get_last_error (const mix_vm_t *vm);
+
+extern const gchar *
+mix_vm_get_last_error_string (const mix_vm_t *vm);
+
+extern const gchar *
+mix_vm_get_error_string (mix_vm_error_t code);
+
 /* run until next breakpoint or end of execution */
 extern mix_vm_status_t
 mix_vm_run (mix_vm_t *vm);
@@ -190,6 +210,7 @@ enum {
   MIX_VM_BP_OK = 0		/* success */
 };
 
+
 extern gint /* if >0 the line no. of the break point */
 mix_vm_set_breakpoint (mix_vm_t *vm, guint lineno);