MACRO-10 is an assembly language with extensive macro facilities for DEC's PDP-10-based Mainframe computer systems, the DECsystem-10 and the DECSYSTEM-20. MACRO-10 is implemented as a two-pass assembler.

Programming examples

A simple "Hello, world!" program in MACRO-10 assembler, to run under TOPS-10, adapted from a specimen in a large collection of "Hello World" programs in various languages: If this program is saved in the file HELLO.MAC, it can be assembled, linked and run like this (the TOPS-10 system prompt is the at the start of lines): The assembly listing file generated by the (Disk LISTing) option to the command: The date ":9" is a Year 2000 problem. A more complex MACRO-10 example program, which renders one version of the 99 Bottles of Beer song, may be examined at the "99 Bottles of Beer" web site. For larger bodies of code, much of the MACRO-10 code for the TOPS-10 and TOPS-20 systems is available in the Trailing Edge PDP-10 tape archives.