KC10 ExecMode Ver6 Mar82

This document is an interoffice memorandum and technical specification detailing the "KC10 Exec Mode Instructions" for the Digital Equipment Corporation KC10 processor. Dated March 7, 1982, with revision history extending to July 1983, its primary purpose is to describe the operation of Exec Mode and I/O instructions, highlighting differences from the KL and KS processors.

The extensive revision history outlines numerous changes and additions across various aspects of the KC10's architecture and instruction set, including:

• Instruction Set Modifications: Updates to specific instructions like XBLT, JRST, PMOVE/PMOVEM, SETCU, RDUBR, UMOVE/UMOVEM, JEN, SWPVA, and many I/O related instructions (e.g., WRAPR, RDAPR, WRCTX, RDCTX).
• Paging System: Detailed descriptions and changes to TOPS-10 and TOPS-20 paging, including pager data structures, hardware and microcode interactions, page address words, CST updates, and page fail conditions and formats.
• System Controls & Context: Revisions related to process context variables (Flag-PC double word), system timers (time base, interval timer, user runtime meter), and address break mechanisms.
• Interrupt and Trap Handling: Changes to trap function words, MUUO and LUUO handling, interrupt vectors, and halt status codes.
• Debugging Features: Introduction and modification of special debugging instructions like RDTRAX, WRTRAX, READTB, WRITTB, and DUMPTB, noting they are not for production microcode.
• System Pages: Layouts and modifications for the Executive Page Table (EPT), User Page Table (UPT), and I/O Page (IOP).

The document serves as a comprehensive update for users and developers working with the KC10 processor, detailing the evolution and specific functionalities of its executive mode and I/O operations.