.orig x3000
LEA R0, hello    ; R0 = &hello
TRAP x22         ; PUTS (print char array at addr in R0)
HALT
hello .stringz "Hello World!"
.end
Or (without PUTS)
.orig x3000
LEA R1, hello        ; R1 = &hello
TOP LDR R0, R1, #0   ; R0 = R1[0]
BRz END              ; if R0 is string terminator (x0000) go to END
TRAP x21             ; else OUT (write char in R0)
ADD R1, R1, #1       ;      increment R1
BR TOP               ;      go to TOP
END HALT
hello .stringz "Hello World!"
.end