This is a transcription of the source code for the Sketchpad program.
Sketchpad was written by Ivan Sutherland and ran on the TX-2 computer at the MIT Lincoln Laboratory.
Sketchpad is one of the most influential computer programs ever written; please see The Importance of Sketchpad to understand its impact on a number of fields.
This listing was produced from the PDF scans made by the Computer History Museum of the program listing supplied by Professor Ivan Sutherland.
This transcription, and the conventions it uses, was created by Jurij Smakov. The conventions are described in Listing Format.
See Assembling the Sketchpad Code.
There are (as of 2025-08-24) likely a number of errors in this transcription - meaning, there will be places where our transcription differs from the source code used to generate the listing the CHM holds. This is primarily because the listing is a photocopy which is hard to read in many places. Superscripts and subscripts are particularly difficult to make out. Unfortunately superscripts and subscripts are important features of the TX-2's assembly language.
See Verifying Listings for an explanation of our general approach to verifying listings of TX-2 software.