Mnemonic Codes, Functions, Special Register Bit Assignments, and Addressing Modes

This document is a technical reference guide that outlines various mnemonic codes, their functions, and associated execution times in microseconds. It covers several operational categories including:

• Extended Memory (MC12): Instructions for changing and reading data fields into the AC bits.
• Interrupt Control: Commands to turn interrupts on or off.
• Real Time Clock (KW12): Instructions for skipping on clock interrupts, managing the clock control, preset, and enable registers, and reading clock status or counter values.
• Mode Change: An instruction to change to LINC mode.
• Power Failure/Restart (KP12): An instruction to skip if power is too low.
• 8-Mode Multiply/Divide (KE12): Instructions for loading step counters, multiplication, division, normalization, various shift operations (left, arithmetic, logical), loading AC into MQ, reading SC into AC, inclusive OR with MQ, and clearing AC or AC and MQ.
• High Speed Perforated Tape Reader (PR8/1) and Punch (PR8/1): Commands for skipping if flags are set, reading/clearing buffers, fetching characters, and loading/punching characters.

Beyond mnemonics, the document provides:

• Special Register Bit Assignments: A table detailing the functions of bits 0-11 for both a "Special Function Register" and a "Tape Extended Operations Register," which include functions like trap enable, half-size characters, maintenance mode, and extended memory address bits.
• Addressing Modes: Descriptions of "Index Class Addressing" and "Half-Word Class Addressing," explaining how operand addresses are determined based on register values (β register) and, for half-words, how bit 0 selects between the left or right half-word.