I was looking at the source for the GreyScale graphics library and I noticed that there were no pushes/pops. This got me to thinking that there are limitations on interrupt routines. If so, what commands are not allowed? Thomas J. Hruska -- thruska@tir.com Shining Light Productions -- "Meeting the needs of fellow programmers" http://www.geocities.com/SiliconValley/Heights/8504 http://shinelight.home.ml.org