Kwanda

KWANDA is an enhanced version of the QANDA subroutine for the PDP-12A computer, designed for interactive display operations. It maintains the core requirements of its predecessor while introducing five primary improvements:

1. Expanded Answer Field: The maximum size of the answer field has been increased to 99, utilizing a two-digit format for specifications.
2. Flexible Memory Residency: The subroutine no longer needs to reside in the current instruction field, allowing for calls from any core segment.
3. Teletype Access: It provides integrated support for teletype input and output from any segment.
4. Optimized I/O: It utilizes faster teletype I/O to reduce display flicker, requiring the clearing of device flags prior to use.
5. Control Character Termination: It allows the user to prematurely terminate a display and trigger specific program options by typing control characters, which return the ASCII code of the input to the main program for processing.

The document includes technical details on the calling sequences for these routines, important memory addresses, and requirements for implementation.