MACRO-11 - Programming Example

Programming Example

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

.TITLE HELLO WORLD .MCALL .TTYOUT,.EXIT HELLO:: MOV #MSG,R1 ;STARTING ADDRESS OF STRING 1$: MOVB (R1)+,R0 ;FETCH NEXT CHARACTER BEQ DONE ;IF ZERO, EXIT LOOP .TTYOUT ;OTHERWISE PRINT IT BR 1$ ;REPEAT LOOP DONE: .EXIT MSG: .ASCIZ /Hello, world!/ .END HELLO

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

.MACRO HELLO ERRORS DETECTED: 0 .LINK HELLO .R HELLO Hello, 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.

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