PTRSER - Paper Tape Reader Service Routine

This document is an assembly listing for "PTRSER," a Paper Tape Reader Service Routine, providing a comprehensive overview of its structure and functionality. It defines system linkages, parameter assignments for the Paper Tape Reader (PTR) control register, special I/O status words, and the Program Interrupt (PI) control register.

The routine includes a PTR Data Block for operational data and a Service Dispatch Table. Detailed assembly code implements various functions:

• PTRINP handles paper tape input, including initialization for new devices, I/O flag settings, and binary mode processing.
• PTRINT manages reader interrupts, checking for completion, handling disconnect requests, saving system state, storing data, verifying power status, detecting end-of-file, and processing special ASCII characters. It also incorporates error handling for checksums.
• Buffer Management routines (PTRI0, PTRI1) manage data buffers, checking for full or empty states, and handling continuous or non-continuous operations.
• PTREND facilitates reader shutdown, clearing flags, and managing block completion conditions.
• PTREX handles PTR disconnection, saves the last data word, clears control flags, and restores system accumulators.
• PTRINI/PTRREL are specific routines for clearing PTR control and console flags.

The document concludes with a comprehensive Symbol Table, listing all defined internal and external symbols with their memory addresses and types, detailing the low-level software implementation for controlling and managing a paper tape reader device.