DEC-10-LBRMA-A-D BLISS-10 Programmers Manual Ver 4 Feb74

This document is the BLISS-10 Programmer's Reference Manual, Version 4, published by Digital Equipment Corporation in February 1974, for the DECsystem-10 computer.

BLISS-10 is described as a low-level "expression language" specifically designed for implementing "System Software." A core concept is that every executable form in BLISS-10 is an expression that computes a value, meaning the language does not have "statements" in the traditional sense. It emphasizes providing the programmer with explicit control over the generated code.

Key characteristics of BLISS-10 include:

• Its design as an "implementation language" to directly reflect the capabilities and architecture of the DECsystem-10.
• The absence of built-in input/output, which is handled directly through assembly-like code or subroutine calls.
• Its sole explicit data mode being the 36-bit binary word, with more complex "data modes" being user-defined via a STRUCTURE mechanism.

The manual itself serves as a comprehensive reference for the language's syntax and semantics, covering basic language definitions (expressions, names, data representation, control flow, declarations, storage), additional machine-dependent features (special functions, character manipulation, machine language instructions), and system features (compilation control, switches, run-time program representation). It is noted as a reference manual, not a tutorial, and assumes familiarity with concepts like ALGOL block structure and recursion. The software is explicitly stated as "support category 4" (no formal support) and not "production quality," with specifications subject to change by DEC.