[SOLVED] Placing subroutines in separate files in arm assembly using the keil IDE

Placing subroutines in separate files in arm assembly using the keil IDE

I am new to ARM Assembly programming using Keil 4, I have been trying to assemble two subroutines in assembly files. One of the subroutines calls the other.

Calling (Branching) a subroutine placed within the same file works, but, if one subroutine is placed in a separate file the following error message comes up

file2.s(8): error: A1163E: Unknown opcode SUBROUTE , expecting opcode or Macro

The code is appended below

FILE 1
;; Directives PRESERVE8 THUMB UNIFIED

      AREA    RESET, DATA, READONLY
      EXPORT  __Vectors
      __Vectors 
      DCD  0x20001000     ; stack pointer value when stack is empty
      DCD  Reset_Handler  ; reset vector
      ALIGN

    AREA    MYCODE, CODE, READONLY
    IMPORT SUBROUTE 
    ENTRY
    EXPORT Reset_Handler 
    Reset_Handler

                 MOV R1, #0x0A      ; Set loop counter
                 MOV R0,#00         ;intilaize resultant register

      loop1 CBZ R1,FINISH       ; if loop counter = 0 then exit the loop
      BL     SUBROUTE
      B loop1           ; next loop         
      FINISH    B FINISH            ; keep looping 
      END                   ; end of program

FILE 2 :

  AREA   subroutine, CODE, READONLY
          EXPORT SUBROUTE
 SUBROUTE   ADD R0,R1           ; Addition opertaion
            SUB R1, #1          ; loop counter decrement
            BX lr
            END

Solution

Armasm labels have to start in the first column. Make sure there are no leading spaces/tabs before SUBROUTE and FINISH on the lines where they are defined. On the other hand, directives (like AREA and IMPORT) must not start in the first column and must have some leading whitespace.