Fortran IV Advanced Software System Programmer's Reference Manual

This manual serves as a comprehensive reference for the FORTRAN IV language and its compiler system for the PDP-9 computer, designed to assist users in writing, compiling, and executing FORTRAN programs within the PDP-9 Advanced Software System.

The document is structured into three main parts:

• Part I: Basic FORTRAN IV Language introduces the elements of the language, including data types (constants, variables, arrays, expressions), and various statement categories such as arithmetic, control (GO TO, IF, DO, CONTINUE, PAUSE, STOP, END), input/output (READ, WRITE, FORMAT), specification (TYPE, DIMENSION, COMMON, EQUIVALENCE, EXTERNAL, DATA), and subprograms (statement functions, intrinsic/library functions, external functions, subroutines, block data subprograms).
• Part II: FORTRAN IV Object Time System details the subprograms responsible for processing compiled FORTRAN IV statements during execution. This includes routines for formatted and unformatted I/O operations, auxiliary I/O statements (BACKSPACE, REWIND, ENDFILE), computed GO TO statements, STOP and PAUSE functions, file commands, clock handling, and adjustable dimensioning. It also covers linking FORTRAN IV programs with MACRO-9 subprograms and lists various object-time errors.
• Part III: PDP-9 Science Library provides in-depth descriptions of mathematical routines, including intrinsic functions (e.g., absolute value, truncation, remaindering, sign transfer, positive difference, float/fix conversion), external functions (e.g., exponential, logarithm, sine, cosine, arctangent, hyperbolic tangent, square root), sub-functions, and the arithmetic package for integer, real, and double-precision arithmetic. This section outlines calling sequences, performance metrics, and storage requirements for each routine.

Appendices further summarize PDP-9 FORTRAN IV statements, note specific exceptions and modifications to the USASI Standard FORTRAN (X3.9-1966), explain FORTRAN IV and MACRO-9 linkage, describe chaining FORTRAN IV programs for memory management, list FORTRAN IV error codes, and detail symbol table sizes for the F4 and F4A compilers.