Overview of the Jupiter EBOX and IBOX

This interoffice memorandum provides a detailed technical overview of the PDP-10 instruction set architecture as implemented for the Jupiter EBOX and IBOX. The document covers:

• Instruction Classes: A categorization of the PDP-10 instruction set based on memory operand requirements, including immediate, single/double memory operand, and single/double memory store instructions.
• Jump and Skip Instructions: Analysis of conditional and unconditional jump/skip behaviors, including proximity-to-zero tests and the logic utilized by the IBOX for prefetching.
• IBOX Functionality: An explanation of the IBOX's role in prefetching, effective address (EA) calculations, and operand setup. It highlights the mechanism for handling branch predictions and complex instructions.
• Complex Instruction Handling: Specific guidelines for the IBOX to set up complex instructions, such as EXTEND, queue operations, and various stack instructions.
• Symbolic Summary: A reference section using pseudo-code to summarize the operand setup requirements for different instruction classes.