;output a string into the top left of the screen
          ORG   0100H       ;Start at addr 0x100
START:    LD    HL,DATA     ;Load the start address of the string
          LD    B,0DH       ;The length of the string (max 255 chars)
          LD    DE,0H       ;Start in the top left corner (D=0-3 -> row; E=0-23 column)
          CALL  84CDH       ;Call the str_out function in ROM
          RET               ;Return from call
DATA:     DB    'HELLO, WORLD!'
          END               ;End marker for the assembler