Amiga HelloWorld

HelloWorld.s

ExecBase = 4                  ;location of the exec.lib
OpenLib = -552                ;offset to the openLibrary function
OpenLibVersion = 34           ;minimum version to use
CloseLib = -414               ;offset to closeLibrary function
PutString = -948              ;offset to putStr() function
  MOVE.L #OpenLibVersion,D0   ;place version of lib in data reg 0
  LEA    DosName,A1           ;place dos.lib name into add reg 1
  MOVE.L ExecBase,A6          ;point to exec.lib's jump table
  JSR    OpenLib(A6)          ;make the jump from exec.lib jump table
  TST.L  D0                   ;check to see if D0 equals zero (fail)
  BEQ.B  NoLibError           ;branch to the NoLibError routinue
  MOVE.L D0,A6                ;addr reg 6 = base addr of dos lib
  MOVE.L #DisplayString,D1    ;data reg 1 = 'Hello World'
  JSR    PutString(A6)        ;make the jump from dos.lib jump table 
  MOVE.L A6,A1                ;base addr of dos lib moved to addr reg 1
  MOVE.L ExecBase,A6          ;exec.lib addr move to addr reg 6
  JSR    CloseLib(A6)         ;make jump from the exec.lib jump table
NoLibError: CLR.L D0          ;clear the register to zero
            RTS               ;quit
DosName:        DC.B "dos.library",0 ;zero-terminated ASCII lib name
DisplayString:  DC.B "Hello World",10,