Automatic Generation of Segmentation Directives on the CDC 6600Computer.

摘要

Central memory is a critical resource on the Aeronautical Systems Division CDC 6600 computer system. This is especially true in the time-sharing environment where the standard maximum field length for a user's program is 60000 to-the-base-8 words of central memory. The amount of central memory required to load and execute a program may be reduced by using the CDC segmentation scheme in which a tree structure of relocatable object modules is specified which permits sharing of central memory. However, the design of an effective tree structure for segmenting a large application program can be very difficult and time consuming. This thesis develops a software processor called SEGMENT that automatically generates segmentation directives for a user's program that describe a tree structure for that program. SEGMENT uses a depth-first search to determine the uses algorithms which correctly position labeled common blocks in this tree structure and which eliminate data preset errors and indirect references to externals.