diff --git a/src/eval.c b/src/eval.c
index e97ddc4..1e2a041 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -812,6 +812,7 @@
 static dictitem_T *find_var __ARGS((char_u *name, hashtab_T **htp, int no_autoload));
 static dictitem_T *find_var_in_ht __ARGS((hashtab_T *ht, int htname, char_u *varname, int no_autoload));
 static hashtab_T *find_var_ht __ARGS((char_u *name, char_u **varname));
+static funccall_T *get_funccal __ARGS((void));
 static void vars_clear_ext __ARGS((hashtab_T *ht, int free_val));
 static void delete_var __ARGS((hashtab_T *ht, hashitem_T *hi));
 static void list_one_var __ARGS((dictitem_T *v, char_u *prefix, int *first));
@@ -21735,7 +21736,7 @@
 
 	if (current_funccal == NULL)
 	    return &globvarht;			/* global variable */
-	return &current_funccal->l_vars.dv_hashtab; /* l: variable */
+	return &get_funccal()->l_vars.dv_hashtab; /* l: variable */
     }
     *varname = name + 2;
     if (*name == 'g')				/* global variable */
@@ -21756,9 +21757,9 @@
     if (*name == 'v')				/* v: variable */
 	return &vimvarht;
     if (*name == 'a' && current_funccal != NULL) /* function argument */
-	return &current_funccal->l_avars.dv_hashtab;
+	return &get_funccal()->l_avars.dv_hashtab;
     if (*name == 'l' && current_funccal != NULL) /* local function variable */
-	return &current_funccal->l_vars.dv_hashtab;
+	return &get_funccal()->l_vars.dv_hashtab;
     if (*name == 's'				/* script variable */
 	    && current_SID > 0 && current_SID <= ga_scripts.ga_len)
 	return &SCRIPT_VARS(current_SID);
@@ -21766,6 +21767,32 @@
 }
 
 /*
+ * Get function call environment based on bactrace debug level
+ */
+    static funccall_T *
+get_funccal()
+{
+    int		i;
+    funccall_T	*funccal;
+    funccall_T	*temp_funccal;
+
+    funccal = current_funccal;
+    if (debug_backtrace_level > 0)
+    {
+        for (i = 0; i < debug_backtrace_level; i++)
+        {
+            temp_funccal = funccal->caller;
+            if (temp_funccal)
+                funccal = temp_funccal;
+	    else
+                /* backtrace level overflow. reset to max */
+                debug_backtrace_level = i;
+        }
+    }
+    return funccal;
+}
+
+/*
  * Get the string value of a (global/local) variable.
  * Note: see get_tv_string() for how long the pointer remains valid.
  * Returns NULL when it doesn't exist.
diff --git a/src/ex_cmds2.c b/src/ex_cmds2.c
index 05baa7e..676cf11 100644
--- a/src/ex_cmds2.c
+++ b/src/ex_cmds2.c
@@ -68,6 +68,10 @@
 #if defined(FEAT_EVAL) || defined(PROTO)
 static int debug_greedy = FALSE;	/* batch mode debugging: don't save
 					   and restore typeahead. */
+static int get_maxbacktrace_level(void);
+static void do_setdebugtracelevel(char_u *arg);
+static void do_checkbacktracelevel(void);
+static void do_showbacktrace(char_u *cmd);
 
 /*
  * do_debug(): Debug mode.
@@ -101,6 +105,10 @@
 #define CMD_FINISH	4
 #define CMD_QUIT	5
 #define CMD_INTERRUPT	6
+#define CMD_BACKTRACE	7
+#define CMD_FRAME	8
+#define CMD_UP		9
+#define CMD_DOWN	10
 
 #ifdef ALWAYS_USE_GUI
     /* Can't do this when there is no terminal for input/output. */
@@ -178,6 +186,7 @@
 # endif
 
 	cmdline_row = msg_row;
+	msg_starthere();
 	if (cmdline != NULL)
 	{
 	    /* If this is a debug command, set "last_cmd".
@@ -197,8 +206,18 @@
 		    case 's': last_cmd = CMD_STEP;
 			      tail = "tep";
 			      break;
-		    case 'f': last_cmd = CMD_FINISH;
-			      tail = "inish";
+		    case 'f':
+			      last_cmd = 0;
+			      if (p[1] == 'r')
+			      {
+				  last_cmd = CMD_FRAME;
+				  tail = "rame";
+			      }
+			      else
+			      {
+				  last_cmd = CMD_FINISH;
+				  tail = "inish";
+			      }
 			      break;
 		    case 'q': last_cmd = CMD_QUIT;
 			      tail = "uit";
@@ -206,6 +225,21 @@
 		    case 'i': last_cmd = CMD_INTERRUPT;
 			      tail = "nterrupt";
 			      break;
+		    case 'b': last_cmd = CMD_BACKTRACE;
+			      if (p[1] == 't')
+				  tail = "t";
+			      else
+				  tail = "acktrace";
+			      break;
+		    case 'w': last_cmd = CMD_BACKTRACE;
+			      tail = "here";
+			      break;
+		    case 'u': last_cmd = CMD_UP;
+			      tail = "p";
+			      break;
+		    case 'd': last_cmd = CMD_DOWN;
+			      tail = "own";
+			      break;
 		    default: last_cmd = 0;
 		}
 		if (last_cmd != 0)
@@ -217,7 +251,7 @@
 			++p;
 			++tail;
 		    }
-		    if (ASCII_ISALPHA(*p))
+		    if (ASCII_ISALPHA(*p) && last_cmd != CMD_FRAME)
 			last_cmd = 0;
 		}
 	    }
@@ -250,7 +284,31 @@
 			/* Do not repeat ">interrupt" cmd, continue stepping. */
 			last_cmd = CMD_STEP;
 			break;
+		    case CMD_BACKTRACE:
+			do_showbacktrace(cmd);
+			continue;
+		    case CMD_FRAME:
+			if (*p == NUL)
+			{
+			    do_showbacktrace(cmd);
+			}
+			else
+			{
+			    p = skipwhite(p);
+			    do_setdebugtracelevel(p);
+			}
+			continue;
+		    case CMD_UP:
+			debug_backtrace_level++;
+			do_checkbacktracelevel();
+			continue;
+		    case CMD_DOWN:
+			debug_backtrace_level--;
+			do_checkbacktracelevel();
+			continue;
 		}
+		/* Going out reset backtrace_level */
+		debug_backtrace_level = 0;
 		break;
 	    }
 
@@ -285,6 +343,92 @@
     debug_did_msg = TRUE;
 }
 
+    static int
+get_maxbacktrace_level(void)
+{
+    char	*p, *q;
+    int		maxbacktrace = 1;
+
+    maxbacktrace = 0;
+    if (sourcing_name != NULL)
+    {
+	p = (char *)sourcing_name;
+	while ((q = strstr(p, "..")) != NULL)
+	{
+	    p = q + 2;
+	    maxbacktrace++;
+	}
+    }
+    return maxbacktrace;
+}
+
+    static void
+do_setdebugtracelevel(char_u *arg)
+{
+    int level;
+
+    level = atoi((char *)arg);
+    if (*arg == '+' || level < 0)
+	debug_backtrace_level += level;
+    else
+	debug_backtrace_level = level;
+
+    do_checkbacktracelevel();
+}
+
+    static void
+do_checkbacktracelevel(void)
+{
+    if (debug_backtrace_level < 0)
+    {
+	debug_backtrace_level = 0;
+	MSG(_("frame is zero"));
+    }
+    else
+    {
+	int max = get_maxbacktrace_level();
+
+	if (debug_backtrace_level > max)
+	{
+	    debug_backtrace_level = max;
+	    smsg((char_u *)_("frame at highest level: %d"), max);
+	}
+    }
+}
+
+    static void
+do_showbacktrace(char_u *cmd)
+{
+    char    *cur;
+    char    *next;
+    int	    i = 0;
+    int	    max = get_maxbacktrace_level();
+
+    if (sourcing_name != NULL)
+    {
+	cur = (char *)sourcing_name;
+	while (!got_int)
+	{
+	    next = strstr(cur, "..");
+	    if (next != NULL)
+		*next = NUL;
+	    if (i == max - debug_backtrace_level)
+		smsg((char_u *)"->%d %s", max - i, cur);
+	    else
+		smsg((char_u *)"  %d %s", max - i, cur);
+	    ++i;
+	    if (next == NULL)
+		break;
+	    *next = '.';
+	    cur = next + 2;
+	}
+    }
+    if (sourcing_lnum != 0)
+       smsg((char_u *)_("line %ld: %s"), (long)sourcing_lnum, cmd);
+    else
+       smsg((char_u *)_("cmd: %s"), cmd);
+}
+
 /*
  * ":debug".
  */
diff --git a/src/globals.h b/src/globals.h
index 0931466..d6abc67 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -231,6 +231,7 @@
 EXTERN int	debug_break_level INIT(= -1);	/* break below this level */
 EXTERN int	debug_did_msg INIT(= FALSE);	/* did "debug mode" message */
 EXTERN int	debug_tick INIT(= 0);		/* breakpoint change count */
+EXTERN int	debug_backtrace_level INIT(= 0); /* breakpoint backtrace level */
 # ifdef FEAT_PROFILE
 EXTERN int	do_profiling INIT(= PROF_NONE);	/* PROF_ values */
 # endif
diff --git a/src/testdir/Make_all.mak b/src/testdir/Make_all.mak
index 6af9b84..33fc345 100644
--- a/src/testdir/Make_all.mak
+++ b/src/testdir/Make_all.mak
@@ -89,6 +89,7 @@
 	test105.out \
 	test106.out \
 	test107.out \
+	test108.out \
 	test_argument_0count.out \
 	test_argument_count.out \
 	test_autocmd_option.out \
diff --git a/src/testdir/test108.in b/src/testdir/test108.in
new file mode 100644
index 0000000..b442cf7
--- /dev/null
+++ b/src/testdir/test108.in
@@ -0,0 +1,87 @@
+Tests for backtrace debug commands.     vim: set ft=vim :
+
+STARTTEST
+:so small.vim
+:function! Foo()
+:   let var1 = 1
+:   let var2 = Bar(var1) + 9
+:   return var2
+:endfunction
+:
+:function! Bar(var)
+:    let var1 = 2 + a:var
+:    let var2 = Bazz(var1) + 4
+:    return var2
+:endfunction
+:
+:function! Bazz(var)
+:    let var1 = 3 + a:var
+:    let var3 = "another var"
+:    return var1
+:endfunction
+:new
+:debuggreedy
+:redir => out
+:debug echo Foo()
+step
+step
+step
+step
+step
+step
+echo "- show backtrace:\n"
+backtrace
+echo "\nshow variables on different levels:\n"
+echo var1
+up
+back
+echo var1
+u
+bt
+echo var1
+echo "\n- undefined vars:\n"
+step
+frame 2
+echo "undefined var3 on former level:"
+echo var3
+fr 0
+echo "here var3 is defined with \"another var\":"
+echo var3
+step
+step
+step
+up
+echo "\nundefined var2 on former level"
+echo var2
+down
+echo "here var2 is defined with 10:"
+echo var2
+echo "\n- backtrace movements:\n"
+b
+echo "\nnext command cannot go down, we are on bottom\n"
+down
+up
+echo "\nnext command cannot go up, we are on top\n"
+up
+b
+echo "fil is not frame or finish, it is file"
+fil
+echo "\n- relative backtrace movement\n"
+fr -1
+frame
+fra +1
+fram
+echo "\n- go beyond limits does not crash\n"
+fr 100
+fra
+frame -40
+fram
+echo "\n- final result 19:"
+cont
+:0debuggreedy
+:redir END
+:$put =out
+:w! test.out
+:qa!
+ENDTEST
+
diff --git a/src/testdir/test108.ok b/src/testdir/test108.ok
new file mode 100644
index 0000000..6315edc
--- /dev/null
+++ b/src/testdir/test108.ok
@@ -0,0 +1,84 @@
+
+
+
+- show backtrace:
+
+  2 function Foo[2]
+  1 Bar[2]
+->0 Bazz
+line 2: let var3 = "another var"
+
+show variables on different levels:
+
+6
+  2 function Foo[2]
+->1 Bar[2]
+  0 Bazz
+line 2: let var3 = "another var"
+3
+->2 function Foo[2]
+  1 Bar[2]
+  0 Bazz
+line 2: let var3 = "another var"
+1
+
+- undefined vars:
+
+undefined var3 on former level:
+Error detected while processing function Foo[2]..Bar[2]..Bazz:
+line    3:
+E121: Undefined variable: var3
+E15: Invalid expression: var3
+here var3 is defined with "another var":
+another var
+
+undefined var2 on former level
+Error detected while processing function Foo[2]..Bar:
+line    3:
+E121: Undefined variable: var2
+E15: Invalid expression: var2
+here var2 is defined with 10:
+10
+
+- backtrace movements:
+
+  1 function Foo[2]
+->0 Bar
+line 3: End of function
+
+next command cannot go down, we are on bottom
+
+frame is zero
+
+next command cannot go up, we are on top
+
+frame at highest level: 1
+->1 function Foo[2]
+  0 Bar
+line 3: End of function
+fil is not frame or finish, it is file
+"[No Name]" --No lines in buffer--
+
+- relative backtrace movement
+
+  1 function Foo[2]
+->0 Bar
+line 3: End of function
+->1 function Foo[2]
+  0 Bar
+line 3: End of function
+
+- go beyond limits does not crash
+
+frame at highest level: 1
+->1 function Foo[2]
+  0 Bar
+line 3: End of function
+frame is zero
+  1 function Foo[2]
+->0 Bar
+line 3: End of function
+
+- final result 19:
+19
+
diff --git a/src/version.c b/src/version.c
index 1abb93e..947d3c8 100644
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1102,
+/**/
     1101,
 /**/
     1100,