10 ; HELLO.ASM
            20 ; ---------
            30 ;
            40 ; THIS ATARI ASSEMBLY PROGRAM
            50 ; WILL PRINT THE "HELLO WORLD"
            60 ; MESSAGE TO THE SCREEN
            70 ;
            0100 ; CIO EQUATES
            0110 ; ===========
0000        0120        *=   $0340     ;START OF IOCB
            0130 IOCB
            0140 ;
0340        0150 ICHID  *=   *+1       ;DEVICE HANDLER
0341        0160 ICDNO  *=   *+1       ;DEVICE NUMBER
0342        0170 ICCOM  *=   *+1       ;I/O COMMAND
0343        0180 ICSTA  *=   *+1       ;I/O STATUS
0344        0190 ICBAL  *=   *+1       ;LSB BUFFER ADDR
0345        0200 ICBAH  *=   *+1       ;MSB BUFFER ADDR
0346        0210 ICPTL  *=   *+1       ;LSB PUT ROUTINE
0347        0220 ICPTH  *=   *+1       ;MSB PUT ROUTINE
0348        0230 ICBLL  *=   *+1       ;LSB BUFFER LEN
0349        0240 ICBLH  *=   *+1       ;MSB BUFFER LEN
034A        0250 ICAX1  *=   *+1       ;AUX BYTE 1
034B        0260 ICAX2  *=   *+1       ;AUX BYTE 1
            0270 ;
0005        0280 GETREC =    5         ;GET TEXT RECORD
0009        0290 PUTREC =    9         ;PUT TEXT RECORD
            0300 ;
E456        0310 CIOV   =    $E456     ;CIO ENTRY VECTOR
02E0        0320 RUNAD  =    $02E0     ;RUN ADDRESS
009B        0330 EOL    =    $9B       ;END OF LINE
            0340 ;
            0350 ; SETUP FOR CIO
            0360 ; -------------
034C        0370        *=   $0600     
0600 A200   0380 START  LDX  #0        ;IOCB 0
0602 A909   0390        LDA  #PUTREC   ;WANT OUTPUT
0604 9D4203 0400        STA  ICCOM,X   ;ISSUE CMD
0607 A91F   0410        LDA  #MSG&255  ;LOW BYTE OF MSG
0609 9D4403 0420        STA  ICBAL,X   ; INTO ICBAL
060C A906   0430        LDA  #MSG/256  ;HIGH BYTE
060E 9D4503 0440        STA  ICBAH,X   ; INTO ICBAH
0611 A900   0450        LDA  #0        ;LENGTH OF MSG
0613 9D4903 0460        STA  ICBLH,X   ; HIGH BYTE
0616 A9FF   0470        LDA  #$FF      ;255 CHAR LENGTH
0618 9D4803 0480        STA  ICBLL,X   ; LOW BYTE
            0490 ;
            0500 ; CALL CIO TO PRINT
            0510 ; -----------------
061B 2056E4 0520        JSR  CIOV      ;CALL CIO
061E 60     0530        RTS            ;EXIT TO DOS
            0540 ;
            0550 ; OUR MESSAGE
            0560 ; -----------
061F 48     0570 MSG    .BYTE "HELLO WORLD!",EOL
0620 45
0621 4C
0622 4C
0623 4F
0624 20
0625 57
0626 4F
0627 52
0628 4C
0629 44
062A 21
062B 9B
            0580 ;
            0590 ; INIT RUN ADDRESS
            0600 ; ----------------
062C        0610        *=   RUNAD     
02E0 0006   0620        .WORD START    
02E2        0630        .END           
0 ERRORS