* gdbtk.c (gdbtk_flush gdbtk_fputs): Buffer up output to make

	disassembly more efficient.
	* (breakpoint_notify):  Include pc in gdbtk_tcl_breakpoint
	callback.
	* (gdb_loc):  Include pc in return value.  Also, return function
	name if arg was specified.
	* (gdb_cmd_stub):  Call gdb_flush to drain internal GDB buffers
	after command completes.
	* (gdbtk_init):  Improve error handling.

	* gdbtk.tcl:  Add lots of comments.  Clean up code.
	* (gdbtk_tcl_fputs):  Make output window redirectable.
	* Add assembly window, and breapoint support.
	* Make button 1 in margin toggle breakpoints.
	* Use stippling to indicate breakpoint disabling.

1 files changed, 792 insertions, 68 deletions

diff --git a/gdb/gdbtk.tcl b/gdb/gdbtk.tcl
index 425041e..3d9f978 100644
--- a/gdb/gdbtk.tcl
+++ b/gdb/gdbtk.tcl
@@ -6,6 +6,8 @@ set current_label {}
 set screen_height 0
 set screen_top 0
 set screen_bot 0
+set current_output_win .command.text
+set cfunc NIL
 
 proc test {} {
 	update_listing {termcap.c foo /etc/termcap 200}
@@ -13,136 +15,353 @@ proc test {} {
 
 proc echo string {puts stdout $string}
 
+if [info exists env(EDITOR)] then {
+	set editor $env(EDITOR)
+	} else {
+	set editor emacs
+}
+
+# GDB callbacks
+#
+#  These functions are called by GDB (from C code) to do various things in
+#  TK-land.  All start with the prefix `gdbtk_tcl_' to make them easy to find.
+#
+
+#
+# GDB Callback:
+#
+#	gdbtk_tcl_fputs (text) - Output text to the command window
+#
+# Description:
+#
+#	GDB calls this to output TEXT to the GDB command window.  The text is
+#	placed at the end of the text widget.  Note that output may not occur,
+#	due to buffering.  Use gdbtk_tcl_flush to cause an immediate update.
+#
+
 proc gdbtk_tcl_fputs {arg} {
-	.command.text insert end "$arg"
-	.command.text yview -pickplace end
+	global current_output_win
+
+	$current_output_win insert end "$arg"
+	$current_output_win yview -pickplace end
+}
+
+#
+# GDB Callback:
+#
+#	gdbtk_tcl_flush () - Flush output to the command window
+#
+# Description:
+#
+#	GDB calls this to force all buffered text to the GDB command window.
+#
+
+proc gdbtk_tcl_flush {} {
+	$current_output_win yview -pickplace end
+	update idletasks
 }
 
-proc gdbtk_tcl_flush {} {update idletasks}
+#
+# GDB Callback:
+#
+#	gdbtk_tcl_query (message) - Create a yes/no query dialog box
+#
+# Description:
+#
+#	GDB calls this to create a yes/no dialog box containing MESSAGE.  GDB
+#	is hung while the dialog box is active (ie: no commands will work),
+#	however windows can still be refreshed in case of damage or exposure.
+#
 
 proc gdbtk_tcl_query {message} {
 	tk_dialog .query "gdb : query" "$message" {} 1 "No" "Yes"
 	}
 
-if [info exists env(EDITOR)] then {
-	set editor $env(EDITOR)
-	} else {
-	set editor emacs
-}
+#
+# GDB Callback:
+#
+#	gdbtk_start_variable_annotation (args ...) - 
+#
+# Description:
+#
+#	Not yet implemented.
+#
 
 proc gdbtk_tcl_start_variable_annotation {valaddr ref_type stor_cl cum_expr field type_cast} {
 	echo "gdbtk_tcl_start_variable_annotation $valaddr $ref_type $stor_cl $cum_expr $field $type_cast"
 }
 
+#
+# GDB Callback:
+#
+#	gdbtk_end_variable_annotation (args ...) - 
+#
+# Description:
+#
+#	Not yet implemented.
+#
+
 proc gdbtk_tcl_end_variable_annotation {} {
 	echo gdbtk_tcl_end_variable_annotation
 }
 
-proc insert_breakpoint_tag {win line} {
-	$win configure -state normal
-	$win delete $line.0
-	$win insert $line.0 "B"
-	$win tag add $line $line.0
-	$win tag bind $line <1> {
-#		echo "tag %W %X %Y %x"
-#		echo "tag names [$wins($cfile) tag names]"
-	}
-
-	$win configure -state disabled
+#
+# GDB Callback:
+#
+#	gdbtk_tcl_breakpoint (action bpnum file line) - Notify the TK
+#	interface of changes to breakpoints.
+#
+# Description:
+#
+#	GDB calls this to notify TK of changes to breakpoints.  ACTION is one
+#	of:
+#		create		- Notify of breakpoint creation
+#		delete		- Notify of breakpoint deletion
+#		enable		- Notify of breakpoint enabling
+#		disable		- Notify of breakpoint disabling
+#
+#	All actions take the same set of arguments:  BPNUM is the breakpoint
+#	number,  FILE is the source file and LINE is the line number, and PC is
+#	the pc of the affected breakpoint.
+#
+
+proc gdbtk_tcl_breakpoint {action bpnum file line pc} {
+	${action}_breakpoint $bpnum $file $line $pc
 }
 
-proc delete_breakpoint_tag {win line} {
-	$win configure -state normal
-	$win delete $line.0
-	$win insert $line.0 " "
-	$win tag delete $line
-	$win configure -state disabled
-}
-
-# Callback from GDB to notify us of breakpoint creation.
-
-proc create_breakpoint {bpnum file line} {
+#
+# Local procedure:
+#
+#	create_breakpoint (bpnum file line pc) - Record breakpoint info in TK land
+#
+# Description:
+#
+#	GDB calls this indirectly (through gdbtk_tcl_breakpoint) to notify TK
+#	land of breakpoint creation.  This consists of recording the file and
+#	line number in the breakpoint_file and breakpoint_line arrays.  Also,
+#	if there is already a window associated with FILE, it is updated with
+#	a breakpoint tag.
+#
+
+proc create_breakpoint {bpnum file line pc} {
 	global wins
 	global breakpoint_file
 	global breakpoint_line
+	global pos_to_breakpoint
+	global cfunc
+	global pclist
 
 # Record breakpoint locations
 
 	set breakpoint_file($bpnum) $file
 	set breakpoint_line($bpnum) $line
+	set pos_to_breakpoint($file:$line) $bpnum
 	
-# If there isn't a window for this file, don't try to update it
+# If there's a window for this file, update it
 
 	if [info exists wins($file)] {
 		insert_breakpoint_tag $wins($file) $line
 	}
+
+# If there's an assembly window, update that too
+
+	set win .asm.func_${cfunc}
+	if [winfo exists $win] {
+		set line [lsearch -exact $pclist($cfunc) $pc]
+		incr line
+		insert_breakpoint_tag $win $line
+	}
 }
 
-proc delete_breakpoint {bpnum file line} {
+#
+# Local procedure:
+#
+#	delete_breakpoint (bpnum file line pc) - Delete breakpoint info from TK land
+#
+# Description:
+#
+#	GDB calls this indirectly (through gdbtk_tcl_breakpoint) to notify TK
+#	land of breakpoint destruction.  This consists of removing the file and
+#	line number from the breakpoint_file and breakpoint_line arrays.  Also,
+#	if there is already a window associated with FILE, the tags are removed
+#	from it.
+#
+
+proc delete_breakpoint {bpnum file line pc} {
 	global wins
 	global breakpoint_file
 	global breakpoint_line
+	global pos_to_breakpoint
 
-# Save line number for later
+# Save line number and file for later
 
 	set line $breakpoint_line($bpnum)
 
+	set file $breakpoint_file($bpnum)
+
 # Reset breakpoint annotation info
 
+	unset pos_to_breakpoint($file:$line)
 	unset breakpoint_file($bpnum)
 	unset breakpoint_line($bpnum)
 
-# If there isn't a window for this file, don't try to update it
+# If there's a window for this file, update it
 
 	if [info exists wins($file)] {
 		delete_breakpoint_tag $wins($file) $line
 	}
 }
 
-# This is a callback from C code to notify us of breakpoint changes.  ACTION
-# can be one of create, delete, enable, or disable.
+#
+# Local procedure:
+#
+#	enable_breakpoint (bpnum file line pc) - Record breakpoint info in TK land
+#
+# Description:
+#
+#	GDB calls this indirectly (through gdbtk_tcl_breakpoint) to notify TK
+#	land of a breakpoint being enabled.  This consists of unstippling the
+#	specified breakpoint indicator.
+#
+
+proc enable_breakpoint {bpnum file line pc} {
+	global wins
 
-proc gdbtk_tcl_breakpoint {action bpnum file line} {
-	${action}_breakpoint $bpnum $file $line
+	$wins($file) tag configure $line -fgstipple {}
 }
 
-# Create the popup listing window menu
+#
+# Local procedure:
+#
+#	disable_breakpoint (bpnum file line pc) - Record breakpoint info in TK land
+#
+# Description:
+#
+#	GDB calls this indirectly (through gdbtk_tcl_breakpoint) to notify TK
+#	land of a breakpoint being disabled.  This consists of stippling the
+#	specified breakpoint indicator.
+#
+
+proc disable_breakpoint {bpnum file line pc} {
+	global wins
 
-menu .breakpoint -cursor hand2
-.breakpoint add command -label Break
-.breakpoint add separator
-.breakpoint add command -label "Edit" -command {exec $editor +$selected_line $selected_file &}
-.breakpoint add command -label "Set breakpoint" -command {gdb_cmd "break $selected_file:$selected_line"}
-#.breakpoint add command -label "Clear breakpoint" -command {echo "Clear"}
-#.breakpoint add command -label "Enable breakpoint" -command {echo "Enable"}
-#.breakpoint add command -label "Disable breakpoint" -command {echo "Disable"}
+	$wins($file) tag configure $line -fgstipple gray50
+}
+
+#
+# Local procedure:
+#
+#	insert_breakpoint_tag (win line) - Insert a breakpoint tag in WIN.
+#
+# Description:
+#
+#	GDB calls this indirectly (through gdbtk_tcl_breakpoint) to insert a
+#	breakpoint tag into window WIN at line LINE.
+#
 
-# Come here when button is released in the popup menu
+proc insert_breakpoint_tag {win line} {
+	$win configure -state normal
+	$win delete $line.0
+	$win insert $line.0 "B"
+	$win tag add $line $line.0
+
+	$win configure -state disabled
+}
+
+#
+# Local procedure:
+#
+#	delete_breakpoint_tag (win line) - Remove a breakpoint tag from WIN.
+#
+# Description:
+#
+#	GDB calls this indirectly (through gdbtk_tcl_breakpoint) to remove a
+#	breakpoint tag from window WIN at line LINE.
+#
+
+proc delete_breakpoint_tag {win line} {
+	$win configure -state normal
+	$win delete $line.0
+	$win insert $line.0 " "
+	$win tag delete $line
+	$win configure -state disabled
+}
 
-bind .breakpoint <Any-ButtonRelease-1> {
+#
+# Menu:
+#
+#	file popup menu - Define the file popup menu.
+#
+# Description:
+#
+#	This menu just contains a bunch of buttons that do various things to
+#	the line under the cursor.
+#
+# Items:
+#
+#	Edit - Run the editor (specified by the environment variable EDITOR) on
+#	       this file, at the current line.
+#	Breakpoint - Set a breakpoint at the current line.  This just shoves
+#		a `break' command at GDB with the appropriate file and line
+#		number.  Eventually, GDB calls us back (at gdbtk_tcl_breakpoint)
+#		to notify us of where the breakpoint needs to show up.
+#
+
+menu .file_popup -cursor hand2
+.file_popup add command -label "Not yet set" -state disabled
+.file_popup add separator
+.file_popup add command -label "Edit" -command {exec $editor +$selected_line $selected_file &}
+.file_popup add command -label "Set breakpoint" -command {gdb_cmd "break $selected_file:$selected_line"}
+
+#
+# Bindings:
+#
+#	file popup menu - Define the file popup menu bindings.
+#
+# Description:
+#
+#	This defines the binding for the file popup menu.  Currently, there is
+#	only one, which is activated when Button-1 is released.  This causes
+#	the menu to be unposted, releases the grab for the menu, and then
+#	unhighlights the line under the cursor.  After that, the selected menu
+#	item is invoked.
+#
+
+bind .file_popup <Any-ButtonRelease-1> {
 	global selected_win
 
 # First, remove the menu, and release the pointer
 
-	.breakpoint unpost
-	grab release .breakpoint
+	.file_popup unpost
+	grab release .file_popup
 
 # Unhighlight the selected line
 
 	$selected_win tag delete breaktag
-#	echo "after deleting $selected_win [$selected_win tag names]"
-#	echo "grab [grab current]"
 
 # Actually invoke the menubutton here!
 
 	tk_invokeMenu %W
-#	destroy .breakpoint
-	grab release $selected_win
 }
 
+#
+# Local procedure:
+#
+#	file_popup_menu (win x y xrel yrel) - Popup the file popup menu.
+#
+# Description:
+#
+#	This procedure is invoked as a result of a command binding in the
+#	listing window.  It does several things:
+#		o - It highlights the line under the cursor.
+#		o - It pops up the file popup menu which is intended to do
+#		    various things to the aforementioned line.
+#		o - Grabs the mouse for the file popup menu.
+#
+
 # Button 1 has been pressed in a listing window.  Pop up a menu.
 
-proc breakpoint_menu {win x y xrel yrel} {
+proc file_popup_menu {win x y xrel yrel} {
 	global wins
 	global win_to_file
 	global file_to_debug_file
@@ -151,10 +370,6 @@ proc breakpoint_menu {win x y xrel yrel} {
 	global selected_file
 	global selected_win
 
-	grab $win
-
-#	echo "bpm grab current [grab current]"
-
 # Map TK window name back to file name.
 
 	set file $win_to_file($win)
@@ -174,22 +389,178 @@ proc breakpoint_menu {win x y xrel yrel} {
 
 # Post the menu near the pointer, (and grab it)
 
-	.breakpoint post [expr $x-[winfo width .breakpoint]/2] [expr $y-10]
-	grab .breakpoint
-#	echo "after grab [grab current]"
+	.file_popup entryconfigure 0 -label "$selected_file:$selected_line"
+	.file_popup post [expr $x-[winfo width .file_popup]/2] [expr $y-10]
+	grab .file_popup
 }
 
+#
+# Local procedure:
+#
+#	listing_window_button_1 (win x y xrel yrel) - Handle button 1 in listing window
+#
+# Description:
+#
+#	This procedure is invoked as a result of holding down button 1 in the
+#	listing window.  The action taken depends upon where the button was
+#	pressed.  If it was in the left margin (the breakpoint column), it
+#	sets or clears a breakpoint.  In the main text area, it will pop up a
+#	menu.
+#
+
+proc listing_window_button_1 {win x y xrel yrel} {
+	global wins
+	global win_to_file
+	global file_to_debug_file
+	global highlight
+	global selected_line
+	global selected_file
+	global selected_win
+	global pos_to_breakpoint
+
+# Map TK window name back to file name.
+
+	set file $win_to_file($win)
+
+	set pos [split [$win index @$xrel,$yrel] .]
+
+# Record selected file and line for menu button actions
+
+	set selected_file $file_to_debug_file($file)
+	set selected_line [lindex $pos 0]
+	set selected_col [lindex $pos 1]
+	set selected_win $win
+
+# If we're in the margin, then toggle the breakpoint
+
+	if {$selected_col < 8} {
+		set pos_break $selected_file:$selected_line
+		set pos $file:$selected_line
+		set tmp pos_to_breakpoint($pos)
+		if [info exists $tmp] {
+			set bpnum [set $tmp]
+			gdb_cmd "delete	$bpnum"
+		} else {
+			gdb_cmd "break $pos_break"
+		}
+		return
+	}
+
+# Post the menu near the pointer, (and grab it)
+
+	.file_popup entryconfigure 0 -label "$selected_file:$selected_line"
+	.file_popup post [expr $x-[winfo width .file_popup]/2] [expr $y-10]
+	grab .file_popup
+}
+
+#
+# Local procedure:
+#
+#	asm_window_button_1 (win x y xrel yrel) - Handle button 1 in asm window
+#
+# Description:
+#
+#	This procedure is invoked as a result of holding down button 1 in the
+#	assembly window.  The action taken depends upon where the button was
+#	pressed.  If it was in the left margin (the breakpoint column), it
+#	sets or clears a breakpoint.  In the main text area, it will pop up a
+#	menu.
+#
+
+proc asm_window_button_1 {win x y xrel yrel} {
+	global wins
+	global win_to_file
+	global file_to_debug_file
+	global highlight
+	global selected_line
+	global selected_file
+	global selected_win
+	global pos_to_breakpoint
+	global pclist
+	global cfunc
+
+	set pos [split [$win index @$xrel,$yrel] .]
+
+# Record selected file and line for menu button actions
+
+	set selected_line [lindex $pos 0]
+	set selected_col [lindex $pos 1]
+	set selected_win $win
+
+# Figure out the PC
+
+	set pc [lindex $pclist($cfunc) $selected_line]
+
+# If we're in the margin, then toggle the breakpoint
+
+	if {$selected_col < 8} {
+		set tmp pos_to_breakpoint($pc)
+		if [info exists $tmp] {
+			set bpnum [set $tmp]
+			gdb_cmd "delete	$bpnum"
+		} else {
+			gdb_cmd "break *$pc"
+		}
+		return
+	}
+
+# Post the menu near the pointer, (and grab it)
+
+#	.file_popup entryconfigure 0 -label "$selected_file:$selected_line"
+#	.file_popup post [expr $x-[winfo width .file_popup]/2] [expr $y-10]
+#	grab .file_popup
+}
+
+#
+# Local procedure:
+#
+#	do_nothing - Does absoultely nothing.
+#
+# Description:
+#
+#	This procedure does nothing.  It is used as a placeholder to allow
+#	the disabling of bindings that would normally be inherited from the
+#	parent widget.  I can't think of any other way to do this.
+#
+
 proc do_nothing {} {}
 
+#
+# Local procedure:
+#
+#	create_file_win (filename) - Create a win for FILENAME.
+#
+# Return value:
+#
+#	The new text widget.
+#
+# Description:
+#
+#	This procedure creates a text widget for FILENAME.  It returns the
+#	newly created widget.  First, a text widget is created, and given basic
+#	configuration info.  Second, all the bindings are setup.  Third, the
+#	file FILENAME is read into the text widget.  Fourth, margins and line
+#	numbers are added.
+#
+
 proc create_file_win {filename} {
 	global breakpoint_file
 	global breakpoint_line
 
+# Replace all the dirty characters in $filename with clean ones, and generate
+# a unique name for the text widget.
+
 	regsub -all {\.|/} $filename {} temp
 	set win .text$temp
+
+# Actually create and do basic configuration on the text widget.
+
 	text $win -height 25 -width 80 -relief raised -borderwidth 2 -yscrollcommand textscrollproc -setgrid true -cursor hand2
+
+# Setup all the bindings
+
 	bind $win <Enter> {focus %W}
-#	bind $win <1> {breakpoint_menu %W %X %Y %x %y}
+	bind $win <1> {listing_window_button_1 %W %X %Y %x %y}
 	bind $win <B1-Motion> do_nothing
 	bind $win n {gdb_cmd next ; update_ptr}
 	bind $win s {gdb_cmd step ; update_ptr}
@@ -197,28 +568,176 @@ proc create_file_win {filename} {
 	bind $win f {gdb_cmd finish ; update_ptr}
 	bind $win u {gdb_cmd up ; update_ptr}
 	bind $win d {gdb_cmd down ; update_ptr}
+
+# Open the file, and read it into the text widget
+
 	set fh [open $filename]
 	$win delete 0.0 end
 	$win insert 0.0 [read $fh]
 	close $fh
+
+# Add margins (for annotations) and a line number to each line
+
 	set numlines [$win index end]
 	set numlines [lindex [split $numlines .] 0]
 	for {set i 1} {$i <= $numlines} {incr i} {
 		$win insert $i.0 [format "   %4d " $i]
 		}
 
-	$win tag add wholebuf 0.0 end
-	$win tag bind wholebuf <1> {breakpoint_menu %W %X %Y %x %y}
+# Scan though the breakpoint data base and install any destined for this file
+
 	foreach bpnum [array names breakpoint_file] {
 		if {$breakpoint_file($bpnum) == $filename} {
 			insert_breakpoint_tag $win $breakpoint_line($bpnum)
 			}
 		}
 
+# Disable the text widget to prevent user modifications
+
 	$win configure -state disabled
 	return $win
 }
 
+#
+# Local procedure:
+#
+#	create_asm_win (funcname) - Create an assembly win for FUNCNAME.
+#
+# Return value:
+#
+#	The new text widget.
+#
+# Description:
+#
+#	This procedure creates a text widget for FUNCNAME.  It returns the
+#	newly created widget.  First, a text widget is created, and given basic
+#	configuration info.  Second, all the bindings are setup.  Third, the
+#	function FUNCNAME is read into the text widget.
+#
+
+proc create_asm_win {funcname} {
+	global breakpoint_file
+	global breakpoint_line
+	global current_output_win
+	global pclist
+
+# Replace all the dirty characters in $filename with clean ones, and generate
+# a unique name for the text widget.
+
+	set win .asm.func_${funcname}
+
+# Actually create and do basic configuration on the text widget.
+
+	text $win -height 25 -width 80 -relief raised -borderwidth 2 \
+		-setgrid true -cursor hand2 -yscrollcommand asmscrollproc
+
+# Setup all the bindings
+
+	bind $win <Enter> {focus %W}
+	bind $win <1> {asm_window_button_1 %W %X %Y %x %y}
+	bind $win <B1-Motion> do_nothing
+	bind $win n {gdb_cmd nexti ; update_ptr}
+	bind $win s {gdb_cmd stepi ; update_ptr}
+	bind $win c {gdb_cmd continue ; update_ptr}
+	bind $win f {gdb_cmd finish ; update_ptr}
+	bind $win u {gdb_cmd up ; update_ptr}
+	bind $win d {gdb_cmd down ; update_ptr}
+
+# Disassemble the code, and read it into the new text widget
+
+	set current_output_win $win
+	gdb_cmd "disassemble $funcname"
+	set current_output_win .command.text
+
+	set numlines [$win index end]
+	set numlines [lindex [split $numlines .] 0]
+
+# Delete the first and last lines, cuz these contain useless info
+
+	$win delete 1.0 2.0
+	$win delete {end - 1 lines} end
+
+# Add margins (for annotations) and note the PC for each line
+
+	if [info exists pclist($funcname)] { unset pclist($funcname) }
+	for {set i 1} {$i <= $numlines} {incr i} {
+		scan [$win get $i.0 "$i.0 lineend"] "%s " pc
+		lappend pclist($funcname) $pc
+		$win insert $i.0 "    "
+		}
+
+
+# Scan though the breakpoint data base and install any destined for this file
+
+#	foreach bpnum [array names breakpoint_file] {
+#		if {$breakpoint_file($bpnum) == $filename} {
+#			insert_breakpoint_tag $win $breakpoint_line($bpnum)
+#			}
+#		}
+
+# Disable the text widget to prevent user modifications
+
+	$win configure -state disabled
+	return $win
+}
+
+#
+# Local procedure:
+#
+#	asmscrollproc (WINHEIGHT SCREENHEIGHT SCREENTOP SCREENBOT) - Update the
+#	asm window scrollbar.
+#
+# Description:
+#
+#	This procedure is called to update the assembler window's scrollbar.
+#
+
+proc asmscrollproc {args} {
+	global asm_screen_height asm_screen_top asm_screen_bot
+
+	eval ".asm.scroll set $args"
+	set asm_screen_height [lindex $args 1]
+	set asm_screen_top [lindex $args 2]
+	set asm_screen_bot [lindex $args 3]
+}
+
+#
+# Local procedure:
+#
+#	update_listing (linespec) - Update the listing window according to
+#				    LINESPEC.
+#
+# Description:
+#
+#	This procedure is called from various places to update the listing
+#	window based on LINESPEC.  It is usually invoked with the result of
+#	gdb_loc.
+#
+#	It will move the cursor, and scroll the text widget if necessary.
+#	Also, it will switch to another text widget if necessary, and update
+#	the label widget too.
+#
+#	LINESPEC is a list of the form:
+#
+#	{ DEBUG_FILE FUNCNAME FILENAME LINE }, where:
+#
+#	DEBUG_FILE - is the abbreviated form of the file name.  This is usually
+#		     the file name string given to the cc command.  This is
+#		     primarily needed for breakpoint commands, and when an
+#		     abbreviated for of the filename is desired.
+#	FUNCNAME - is the name of the function.
+#	FILENAME - is the fully qualified (absolute) file name.  It is usually
+#		   the same as $PWD/$DEBUG_FILE, where PWD is the working dir
+#		   at the time the cc command was given.  This is used to
+#		   actually locate the file to be displayed.
+#	LINE - The line number to be displayed.
+#
+#	Usually, this procedure will just move the cursor one line down to the
+#	next line to be executed.  However, if the cursor moves out of range
+#	or into another file, it will scroll the text widget so that the line
+#	of interest is in the middle of the viewable portion of the widget.
+#
+
 proc update_listing {linespec} {
 	global pointers
 	global screen_height
@@ -229,16 +748,26 @@ proc update_listing {linespec} {
 	global win_to_file
 	global file_to_debug_file
 
+# Rip the linespec apart
+
 	set line [lindex $linespec 3]
 	set filename [lindex $linespec 2]
 	set funcname [lindex $linespec 1]
 	set debug_file [lindex $linespec 0]
 
+# Sometimes there's no source file for this location
+
 	if {$filename == ""} {set filename Blank}
 
+# If we want to switch files, we need to unpack the current text widget, and
+# stick in the new one.
+
 	if {$filename != $cfile} then {
 		pack forget $wins($cfile)
 		set cfile $filename
+
+# Create a text widget for this file if necessary
+
 		if ![info exists wins($cfile)] then {
 			set wins($cfile) [create_file_win $cfile]
 			set win_to_file($wins($cfile)) $cfile
@@ -246,16 +775,23 @@ proc update_listing {linespec} {
 			set pointers($cfile) 1.1
 			}
 
+# Pack the text widget into the listing widget, and scroll to the right place
+
 		pack $wins($cfile) -side left -expand yes -in .listing -fill both -after .label
 		$wins($cfile) yview [expr $line - $screen_height / 2]
 		}
 
+# Update the label widget in case the filename or function name has changed
+
 	if {$current_label != "$filename.$funcname"} then {
 		set tail [expr [string last / $filename] + 1]
 		.label configure -text "[string range $filename $tail end] : ${funcname}()"
 		set current_label $filename.$funcname
 		}
 
+# Update the pointer, scrolling the text widget if necessary to keep the
+# pointer in an acceptable part of the screen.
+
 	if [info exists pointers($cfile)] then {
 		$wins($cfile) configure -state normal
 		set pointer_pos $pointers($cfile)
@@ -278,8 +814,196 @@ proc update_listing {linespec} {
 		}
 }
 
+#
+# Local procedure:
+#
+#	update_ptr - Update the listing window.
+#
+# Description:
+#
+#	This routine will update the listing window using the result of
+#	gdb_loc.
+#
+
 proc update_ptr {} {update_listing [gdb_loc]}
 
+#
+# Local procedure:
+#
+#	asm_command - Open up the assembly window.
+#
+# Description:
+#
+#	Create an assembly window if it doesn't exist.
+#
+
+proc asm_command {} {
+	global cfunc
+
+	if ![winfo exists .asm] {
+		set cfunc *None*
+		set win .asm.func_${cfunc}
+		toplevel .asm
+		wm minsize .asm 1 1
+
+		label .asm.label -text "*NIL*" -borderwidth 2 -relief raised
+		text $win -height 25 -width 80 -relief raised -borderwidth 2 \
+			-setgrid true -cursor hand2 \
+			-yscrollcommand asmscrollproc
+		scrollbar .asm.scroll -orient vertical -command {$win yview}
+		frame .asm.buts
+
+		button .asm.stepi -text Stepi \
+			-command {gdb_cmd stepi ; update_ptr}
+		button .asm.nexti -text Nexti \
+			-command {gdb_cmd nexti ; update_ptr}
+		button .asm.continue -text Continue \
+			-command {gdb_cmd continue ; update_ptr}
+		button .asm.finish -text Finish \
+			-command {gdb_cmd finish ; update_ptr}
+		button .asm.up -text Up -command {gdb_cmd up ; update_ptr}
+		button .asm.down -text Down \
+			-command {gdb_cmd down ; update_ptr}
+		button .asm.bottom -text Bottom \
+			-command {gdb_cmd {frame 0} ; update_ptr}
+		button .asm.close -text Close -command {destroy .asm}
+
+		pack .asm.label -side top -fill x
+		pack .asm.stepi .asm.nexti .asm.continue .asm.finish .asm.up \
+		     .asm.down .asm.bottom .asm.close -side left -in .asm.buts
+		pack .asm.buts -side top -fill x
+		pack $win -side left -expand yes -fill both
+		pack .asm.scroll -side left -fill y
+
+		update
+	}
+}
+
+#
+# Local procedure:
+#
+#	update_assembly - Update the assembly window.
+#
+# Description:
+#
+#	This procedure updates the assembly window.
+#
+
+proc update_assembly {linespec} {
+	global asm_pointers
+	global screen_height
+	global screen_top
+	global screen_bot
+	global wins cfunc
+	global current_label
+	global win_to_file
+	global file_to_debug_file
+	global current_asm_label
+	global pclist
+	global asm_screen_height asm_screen_top asm_screen_bot
+
+# Rip the linespec apart
+
+	set pc [lindex $linespec 4]
+	set line [lindex $linespec 3]
+	set filename [lindex $linespec 2]
+	set funcname [lindex $linespec 1]
+	set debug_file [lindex $linespec 0]
+
+	set win .asm.func_${cfunc}
+
+# Sometimes there's no source file for this location
+
+	if {$filename == ""} {set filename Blank}
+
+# If we want to switch funcs, we need to unpack the current text widget, and
+# stick in the new one.
+
+	if {$funcname != $cfunc} then {
+		pack forget $win
+		set cfunc $funcname
+
+		set win .asm.func_${cfunc}
+
+# Create a text widget for this func if necessary
+
+		if ![winfo exists $win] then {
+			create_asm_win $cfunc
+			set asm_pointers($cfunc) 1.1
+			set current_asm_label NIL
+			}
+
+# Pack the text widget, and scroll to the right place
+
+		pack $win -side left -expand yes -fill both \
+			-after .asm.buts
+		set line [lsearch -exact $pclist($cfunc) $pc]
+		incr line
+		$win yview [expr $line - $asm_screen_height / 2]
+		}
+
+# Update the label widget in case the filename or function name has changed
+
+	if {$current_asm_label != $funcname} then {
+		.asm.label configure -text $funcname
+		set current_asm_label $funcname
+		}
+
+# Update the pointer, scrolling the text widget if necessary to keep the
+# pointer in an acceptable part of the screen.
+
+	if [info exists asm_pointers($cfunc)] then {
+		$win configure -state normal
+		set pointer_pos $asm_pointers($cfunc)
+		$win configure -state normal
+		$win delete $pointer_pos
+		$win insert $pointer_pos " "
+
+# Map the PC back to a line in the window		
+
+		set line [lsearch -exact $pclist($cfunc) $pc]
+
+		if {$line == -1} {
+			echo "Can't find PC $pc"
+			return
+			}
+
+		incr line
+
+		set pointer_pos [$win index $line.1]
+		set asm_pointers($cfunc) $pointer_pos
+
+		$win delete $pointer_pos
+		$win insert $pointer_pos "\xbb"
+
+		if {$line < $asm_screen_top + 1
+		    || $line > $asm_screen_bot} then {
+			$win yview [expr $line - $asm_screen_height / 2]
+			}
+
+#		echo "Picking line $line"
+#		$win yview -pickplace $line
+
+		$win configure -state disabled
+		}
+}
+
+proc update_ptr {} {
+	update_listing [gdb_loc]
+	if [winfo exists .asm] {
+		update_assembly [gdb_loc]
+	}
+}
+
+#
+# Window:
+#
+#	listing window - Define the listing window.
+#
+# Description:
+#
+#
+
 # Setup listing window
 
 frame .listing
@@ -325,6 +1049,7 @@ button .exit -text Exit -command {gdb_cmd quit}
 button .up -text Up -command {gdb_cmd up ; update_ptr}
 button .down -text Down -command {gdb_cmd down ; update_ptr}
 button .bottom -text "Bottom" -command {gdb_cmd {frame 0} ; update_ptr}
+button .asm_but -text "Asm" -command {asm_command ; update_ptr}
 
 proc files_command {} {
 	toplevel .files_window
@@ -348,7 +1073,7 @@ button .files -text Files -command files_command
 
 pack .listing -side bottom -fill both -expand yes
 #pack .test -side bottom -fill x
-pack .start .step .next .continue .finish .up .down .bottom .files .exit -side left
+pack .start .step .next .continue .finish .up .down .bottom .asm_but .files .exit -side left
 toplevel .command
 
 # Setup command window
@@ -396,4 +1121,3 @@ proc delete_char {win} {
 }
 
 wm minsize .command 1 1
-