Assembler Programming Under Etos

Summary

This document provides a guide to assembly language programming within the ETOS environment. It covers the following key areas:

• Development Environment: Programs must be developed using OS/8-compatible assemblers (such as PAL8, SABR, RALF, or MACREL) but can be executed as core image files under COS. Developers are advised to avoid OS/8-specific dependencies if the program is intended for use under COS.
• Instruction Compatibility: Most assembly instructions and I/O transfers (IOTs) function identically to those on a stand-alone PDP-8, with close correlation between ETOS and PDP-8 operations.
• Terminal IOTs: The document details specific IOT instructions for managing terminal input and output, including keyboard buffer control (KCF, KSF, KCC, KCL, KRS, KRB), status management (GETSTAT, SETSTAT), and teleprinter operations (TCF, TCL, TPC, TSK, TLS).
• Extended Memory: It explains how data and instruction fields are handled in the ETOS virtual memory environment, noting that instructions like CDF (Change Data Field) function as they do on a standard PDP-8, provided that adequate memory has been allocated.