version 0.4

10 files changed, 122 insertions, 28 deletions

diff --git a/NEWS b/NEWS
index c01eb86..6785f3d 100644
--- a/NEWS
+++ b/NEWS
@@ -6,7 +6,7 @@ See the end for copying conditions.
 Please send mdk bug reports to bug-mdk@gnu.org.
 
 ---------------------------------------------------------------------------
-* Version 0.4
+* Version 0.4 (22/07/01)
 
 ** Split mode: gmixvm can now be run with the MIXVM, MIXAL and Devices
    windows detached (instead of arranged in a notebook).
diff --git a/doc/mdk_gstart.texi b/doc/mdk_gstart.texi
index 25764a0..70ded05 100644
--- a/doc/mdk_gstart.texi
+++ b/doc/mdk_gstart.texi
@@ -445,6 +445,7 @@ MIX >
 @end example
 
 Other useful commands for debugging are @code{tracing} (which turns on
-tracing of executed intructions) and @code{weval} (which evaluates
+tracing of executed intructions), @code{pbt} (which prints a backtrace
+of executed instructions) and @code{weval} (which evaluates
 w-expressions on the fly). For a complete description of all available
 MIX commands, @xref{mixvm}.
diff --git a/doc/mdk_mixvm.texi b/doc/mdk_mixvm.texi
index f5538cd..480abbc 100644
--- a/doc/mdk_mixvm.texi
+++ b/doc/mdk_mixvm.texi
@@ -373,6 +373,53 @@ actual MIXAL code that was compiled into the executed instruction. The
 tracing behaviour is stored as a configuration parameter in @file{~/.mdk}.
 @end deffn
 
+@deffn {debug command} pbt [INS_NUMBER]
+This command prints a backtrace of executed instructions. Its optional
+argument @var{ins_number} is the number of instructions to print. If it
+is omitted or equals zero, all executed instructions are printed. For
+instance, if you compile and load the following program (@file{bt.mixal}):
+
+@example
+    ORIG 0
+BEG JMP *+1
+    JMP *+1
+FOO JMP BAR
+BAR HLT
+    END BEG
+@end example
+
+@noindent
+you could get the following traces:
+
+@example
+MIX > load bt
+Program loaded. Start address: 0
+MIX > next
+MIX > pbt 
+#0      BEG     in bt.mixal:2
+MIX > next
+MIX > pbt
+#0      1       in bt.mixal:3
+#1      BEG     in bt.mixal:2
+MIX > run
+Running ...
+... done
+MIX > pbt 3
+#0      BAR     in bt.mixal:5
+#1      FOO     in bt.mixal:4
+#2      1       in bt.mixal:3
+MIX > pbt
+#0      BAR     in bt.mixal:5
+#1      FOO     in bt.mixal:4
+#2      1       in bt.mixal:3
+#3      BEG     in bt.mixal:2
+MIX >
+@end example
+
+Note that the executed instruction trace gives you the label of the
+executed line or, if it has no label, the its address.
+@end deffn
+
 As you have probably observed, @code{mixvm} prints timing statistics
 when running programs. This behaviour can be controlled using the
 @code{timing} command (@pxref{Configuration commands}).
diff --git a/mixlib/mix_vm.c b/mixlib/mix_vm.c
index 0e9f61b..692f84d 100644
--- a/mixlib/mix_vm.c
+++ b/mixlib/mix_vm.c
@@ -67,6 +67,12 @@ vm_reset_reload_ (mix_vm_t *vm, gboolean is_reload)
       }
   if (!is_reload)
     mix_vm_clear_all_breakpoints (vm);
+
+  if (vm->address_list)
+    {
+      g_slist_free (vm->address_list);
+      vm->address_list = NULL;
+    }
 }
 
 
@@ -82,6 +88,7 @@ mix_vm_new (void)
   vm->symbol_table = NULL;
   vm->src_file = NULL;
   vm->pred_list = mix_predicate_list_new (vm);
+  vm->address_list = NULL;
   
   for (i = 0; i < BD_NO_; ++i)
     vm->devices[i] = NULL;
@@ -106,6 +113,8 @@ mix_vm_delete (mix_vm_t * vm)
   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);
+  if (vm->pred_list != NULL) mix_predicate_list_delete (vm->pred_list);
+  if (vm->address_list != NULL) g_slist_free (vm->address_list);
   for (i = 0; i < BD_NO_; ++i)
     mix_device_delete (vm->devices[i]);
   mix_vm_clock_delete (vm->clock);
@@ -418,25 +427,6 @@ mix_vm_get_lineno_address (const mix_vm_t *vm, guint lineno)
 }
 
 
-/* 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)
@@ -447,6 +437,9 @@ mix_vm_run (mix_vm_t *vm)
   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) ) 
 	return MIX_VM_ERROR;
       else
@@ -468,6 +461,9 @@ mix_vm_exec_next (mix_vm_t *vm)
   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;
+  vm->address_list =
+    g_slist_prepend (vm->address_list,
+		     GINT_TO_POINTER ((gint)get_loc_ (vm)));
   mix_word_to_ins_uncheck (get_cell_ (vm, get_loc_ (vm)), ins);
   if (!(*ins_handlers_[ins.opcode]) (vm, &ins))
     return MIX_VM_ERROR;
@@ -636,3 +632,10 @@ mix_vm_get_uptime (const mix_vm_t *vm)
   return mix_vm_clock_get_time (get_clock_ (vm));
 }
 
+/* Get the list of addresses for executed instructions */
+const GSList *
+mix_vm_get_backtrace (const mix_vm_t *vm)
+{
+  g_return_val_if_fail (vm != NULL, NULL);
+  return get_address_list_ (vm);
+}
diff --git a/mixlib/mix_vm.h b/mixlib/mix_vm.h
index d0403cc..d3f4e3f 100644
--- a/mixlib/mix_vm.h
+++ b/mixlib/mix_vm.h
@@ -151,12 +151,6 @@ mix_vm_get_address_lineno (const mix_vm_t *vm, mix_address_t addr);
 extern mix_address_t
 mix_vm_get_lineno_address (const mix_vm_t *vm, guint lineno);
 
-/* Reposition program counter and reset state so that a loaded
-   program can be restarted.
-*/
-extern void
-mix_vm_reset_program (mix_vm_t *vm);
-
 /* continue execution of instructions in memory */
 /* Possible outcomes */
 enum {
@@ -220,6 +214,10 @@ mix_vm_get_last_breakpoint_message (const mix_vm_t *vm);
 extern mix_time_t
 mix_vm_get_uptime (const mix_vm_t *vm);
 
+/* Get the list of addresses for executed instructions */
+extern const GSList *
+mix_vm_get_backtrace (const mix_vm_t *vm);
+
 
 #endif /* MIX_VM_H */
 
diff --git a/mixlib/mix_vm_command.c b/mixlib/mix_vm_command.c
index 264c9ff..0ccfd7b 100644
--- a/mixlib/mix_vm_command.c
+++ b/mixlib/mix_vm_command.c
@@ -126,6 +126,7 @@ DEC_FUN (cbpr_);
 DEC_FUN (cbpm_);
 DEC_FUN (cbpc_);
 DEC_FUN (cbpo_);
+DEC_FUN (pbt_);
 
 
 /* internal command info struct */
@@ -198,6 +199,8 @@ command_ commands_[] = {
     "w2d WORD"},
   { "tracing", cmd_tracing_, N_("Turn on/off instruction tracing"),
     "tracing [on|off]"},
+  { "pbt", cmd_pbt_, N_("Print backtrace of executed instructions"),
+    "pbt [INS_NO] (e.g pbt 5)"},
   { "timing", cmd_timing_, N_("Turn on/off timing statistics"),
     "timing [on|off]"},
   { "devdir", cmd_devdir_, N_("Print/set devices directory"),
@@ -1699,4 +1702,36 @@ cmd_cbpc_ (mix_vm_cmd_dispatcher_t *dis, const gchar *arg)
   return TRUE;
 }
 
-    
+static gboolean
+cmd_pbt_ (mix_vm_cmd_dispatcher_t *dis, const gchar *arg)
+{
+  enum {SIZE = 256};
+  static gchar BUFFER[SIZE];
+  gint no = atoi (arg);
+  gint k = 0, address;
+  guint line;
+  const mix_src_file_t *file = mix_vm_get_src_file (dis->vm);
+  char *name = file ? g_basename (mix_src_file_get_path (file)) : NULL;
+
+  const GSList *add = mix_vm_get_backtrace (dis->vm);
+  while (add && (no == 0 || k < no))
+    {
+      BUFFER[0] = '\0';
+      address = GPOINTER_TO_INT (add->data);
+      line = mix_vm_get_address_lineno (dis->vm, address);
+      if (line && file)
+	{
+	  int j = 0;
+	  snprintf (BUFFER, SIZE, "%s", mix_src_file_get_line (file, line));
+	  while (!isspace (BUFFER[j])) j++;
+	  BUFFER[j] = '\0';
+	}
+      if (strlen (BUFFER) == 0)	snprintf (BUFFER, SIZE, "%d", address);
+      fprintf (dis->out, "#%d\t%s\tin %s%s:%d\n", k, BUFFER, name,
+	       MIX_SRC_DEFEXT, line);
+      ++k;
+      add = add->next;
+    }
+  /*  if (name) g_free (name); */
+  return TRUE;
+}
diff --git a/mixlib/mix_vm_command.h b/mixlib/mix_vm_command.h
index 6c60264..5d5ebca 100644
--- a/mixlib/mix_vm_command.h
+++ b/mixlib/mix_vm_command.h
@@ -75,6 +75,7 @@ typedef enum {
   MIX_CMD_WEVAL,		/* evaluate a w-expression */
   MIX_CMD_W2D,			/* print word in decimal notation */
   MIX_CMD_TRACING,		/* enable/disable instruction traces */
+  MIX_CMD_PBT,			/* print backtrace */
   MIX_CMD_TIMING,		/* enable/disable timing statistics */
   MIX_CMD_DEVDIR,		/* print/set device directory */
   MIX_CMD_INVALID,		/* invalid command identifier */
diff --git a/samples/.cvsignore b/samples/.cvsignore
index bebe302..21be91e 100644
--- a/samples/.cvsignore
+++ b/samples/.cvsignore
@@ -1,7 +1,9 @@
 Makefile
 Makefile.in
+bt.mix
 cardwr.dev
 cbp.mix
+cbp.mls
 disk0.dev
 disk1.dev
 disk2.dev
diff --git a/samples/bt.mixal b/samples/bt.mixal
new file mode 100644
index 0000000..00306ae
--- /dev/null
+++ b/samples/bt.mixal
@@ -0,0 +1,6 @@
+    ORIG 0
+BEG JMP *+1
+    JMP *+1
+FOO JMP BAR
+BAR HLT
+    END BEG
diff --git a/samples/cbp.mixal b/samples/cbp.mixal
index b436c8c..8c7b394 100644
--- a/samples/cbp.mixal
+++ b/samples/cbp.mixal
@@ -7,6 +7,7 @@ START	ENTA	100
 	CMPA	1001 	* cmp flag changed
 	CMPX	1000    * cmp flag changed
 	DIV	1002    * over toggle
+	HLT
 	END	START