ORG $100: this code commanded assembler to set the location counter to 100.PORTB EQU $1004: this is memory address which is allotted to the I/O port B.START LDAA #$34:34 is moved from memory location to register A.

XAT: it represented as a label.LDAA $567: the memory location content 4567 is loaded in reg A.CLRA: this is the clear command to clear the value in Register and set the value as 0.STAA PORT B: the contents from register A are copied to the Port B which address location is specified in earlier.JMP XAT: the upcoming instruction is jumped to the label XAT. ‘