Undoing a Command

You can restore EPIC to a previous state by entering the Undo command in the EPIC Command Line dialog box or by selecting Undo Last Action or Undo Last Change from the Edit menu. You can undo the last command, undo every command prior to a designated command, or you can undo prior to the last command that made a change to the design.

From the Command Line

To invoke the Undo command from the command line, type the following command in the EPIC Command Line dialog box.

undo [-c] | [command_number]

Undo (without an argument) cancels the previous action.
Undo command_number undoes back to that command.
Command_number is a number between 0 and 32,000.
The -c option negates the last command that made a change to the design.

You cannot undo Load, Unload, Save or Save As commands.

NOTE

If you invoke a command that takes a considerable amount of time to execute, it is recommended that you save after executing the command. Subsequent commands then “undo” much more quickly. Remember that every save restarts the EPL file.

You can find the number of a particular command by looking in the command log file located in the directory from which you are running EPIC. This file has the same root name as the design and a .epl extension. Every time EPIC is invoked, a new command log file is created and each command is automatically entered into the file by number and description. When an EPIC session terminates normally, the EPL file is deleted. Here is a sample of a command log file.

#Initialization completed.

#Copyright 1991-1994 by XILINX Inc.  All rights reserved.

#EPIC 6.1 - ready for input.

#1

select net S21

#2

autoroute

#3

post find

getattr find type name auto_pan auto_clear

#4

setattr find name 7N208 type comp auto_clear FALSE\ auto_pan

find comp 7N208

#ERROR - find: Component "7N208" not found.

#5

unpost find

#6

getattr

#design_name = main_dec

#epic_version = 1.120

#speed = 100

#edit_mode = No-Logic-Changes

#flush_rate = 1

#auto_deselect = FALSE

#auto_hilite = FALSE

#stub_trim = TRUE

#auto_route = TRUE

#enhanced_routing = TRUE

#delay_based = TRUE

#disable_draw = FALSE

#7

select net $31-$1N19

#8

unroute

From the Edit Menu

Select Undo Last Action from the Edit menu. Undo Last Action cancels the previous command. Undo Last Change cancels the last change that was made to the design.