Editing Microprograms

Microprograms can be edited in the Microprogram Editor Window. Conceptually, you are directly manipulating bits within the control store of the computer. Consequently, only the binary code can be edited. No other editing changes are possible (or appropriate). As you edit a microinstruction, the disassembled mal (micro assembly language) version will be updated to reflect the changes. Copy, cut, and paste operations are supported but each works only with an entire 36-bit microinstruction. You can not copy, cut, or paste just a portion of a microinstruction.

The microprogram editor responds to the keystrokes listed below. In most cases the results are what you would expect though there are some differences. Since you cannot delete a bit in the control store, the "Backspace" key is just an alternate for the left arrow key. The "Delete" key doesn't delete a bit; it resets the bit to zero and moves right one bit (as though you had tapped the '0' key). The "Enter" key behaves like the down arrow key.

Microprogram Editor Keystrokes



Left Arrow Move one bit to the left (with wrap-around)
Backspace Same as left arrow
Home Move to the left-most bit
Right Arrow Move one bit to the right (with wrap-around)
End Move to the right-most bit
Up Arrow Move up one line
Page Up Move up one page
Ctrl-Home Move up to the first microinstruction
Down Arrow Move down one line
Enter Same as down arrow
Page Down Move down one page
Ctrl-End Move down to the last microinstruction
Ctrl-C Copy the microinstruction on the current line to the clipboard
Ctrl-V Paste the microinstruction on the clipboard to the current line (replacing the existing microinstruction)
Ctrl-X Cut the microinstruction on the current line (copy it to the clipboard and replace it with all zeroes)
0 Set the current bit to 0 and move right one bit (with wrap-around)
Delete The same as 0
1 Set the current bit to 1 and move right one bit (with wrap-around)