Text Exec Window
The Text Exec  Window provides a way to type calculator commands and view results.  In general, all of the functionality provided is much easier to utilize in the emulator window.  The Text Exec Window is left over from very early versions of the debugging system.

In the window on the right there is a command area on the bottom.  Type calculator commands as you would on the calculator and then press enter.  The commands are then copied into the large upper area, the commands are executed and the results copied under the command string in the window.  The sample shows three sets of commands executed with various results.  The picture below shows the emulator window after the above commands have been performed.