MACRO-11

MACRO-11
Paradigms	non-structured, imperative
Family	Assembly language
Developer	Digital Equipment Corporation
First appeared	1980;45 years ago (1980)
Typing discipline	Untyped
Scope	Lexical
Implementation language	assembly language
Platform	PDP-11
OS	All DEC PDP-11
Influenced by
PAL-11R
Influenced
VAX MACRO

MACRO-11 is an assembly language with macro facilities, designed for PDP-11 minicomputer family from Digital Equipment Corporation (DEC). It is the successor to Program Assembler Loader (PAL-11R), an earlier version of the PDP-11 assembly language without macro facilities.

MACRO-11 was supported on all DEC PDP-11 operating systems. PDP-11 Unix systems also include an assembler (named as ), structurally similar to MACRO-11, but with different syntax and fewer features. The MACRO-11 assembler (and programs created by it) could also run under the RSX-11 compatibility mode of OpenVMS on VAX. ^[1]

(The stated date in the summary is wrong. I was programming a PDP 11/34 in Macro-11 under DOS/BATCH in 1974)

Programming example

A complete "Hello, World!" program in PDP-11 macro assembler, to run under RT-11:

.TITLEHELLOWORLD.MCALL.TTYOUT,.EXITHELLO::MOV#MSG,R1  ;STARTING ADDRESS OF STRING1$:MOVB(R1)+,R0;FETCH NEXT CHARACTERBEQDONE;IF ZERO, EXIT LOOP.TTYOUT;OTHERWISE PRINT ITBR1$;REPEAT LOOPDONE:.EXITMSG:.ASCIZ/Hello,world!/.ENDHELLO

The .MCALL pseudo-op warns the assembler that the code will be using the .TTYOUT and .EXIT macros. The .TTYOUT and .EXIT macros are defined in the standard system macro library to expand to the EMT instructions to call the RT-11 monitor to perform the requested functions.

If this file is HELLO.MAC, the RT-11 commands to assemble, link and run (with console output shown) are as follows:

.MACROHELLOERRORSDETECTED:0.LINKHELLO.RHELLOHello,world!.

(The RT-11 command prompt is ".")

For a more complicated example of MACRO-11 code, two examples chosen at random are Kevin Murrell's KPUN.MAC, or Farba Research's JULIAN routine. More extensive libraries of PDP-11 code can be found in the Metalab freeware and Trailing Edge archives. ^{[2] [3]}

References

1. "VAX/VMS Software Language and Tools Handbook" (PDF). Bitsavers.org. 1985. Retrieved 2020-12-31.
2. Metalab
3. Trailing Edge

External links

• RSX-11M-Plus RMS-ll Macro Programmer's Guide (April 1983)
• Michael Singer, PDP-11. Assembler Language Programming and Machine Organization, John Wiley & Sons, NY: 1980.