I'm trying to implement a basic program in LC3 Assembly, but the assembler seems not to be recognising one of the labels. I wonder why it's not recognising just the last one:
.ORIG 0x300
NUMBER: .FILL x0006
NUMBER2: .FILL x0003
R1MAGG: .FILL x0999
UGUALI: .FILL 0x500
R1MIN: .FILL x0001
LD R1, NUMBER
LD R2, NUMBER2
;I stored in R1 and R2 2 numbers
;Now I compare them
NOT R2, R2
ADD R2, R2, #1
ADD R3, R1, R2
BRp R1MAGGIORE
BRn R1MINORE
LD R4, UGUALI
JSR EOP
R1MAGGIORE:
LD R4, R1MAGG
JSR EOP
R1MINORE:
LD R4, R1MIN
JSR EOP
EOP:
.END
And this is the error it's returning: LINE 28: Unrecognized opcode or syntax error at or before '.END'
CodePudding user response:
Try EOP: HALT
and then the .END
on the next line as you have it. Suspect it is complaining about missing instruction, but you really should terminate the program with a HALT
(trap) instruction anyway.
Are you sure you want .ORIG
at 0x300 not x3000?
You might consider putting your data after the code, to prevent the simulator from attempting to execute your data. Otherwise you can put a BR MAIN
as the first instruction (i.e. before/in-front-of the data), and a label MAIN:
where you have the programs first real instructions, so that it will jump around your data and to your program starting point.