Step-1: MVI A, 42H given 42 value in hexadecimal and storing value in Accumulator A.
For solving problem, convert (42) 16 into decimal is (66) 10
Step-2: MVI B, 05H given 05 value in hexadecimal and storing value in Accumulator B.
For solving problem, convert (05) 16 into decimal is (05) 10
Step-3: ADD B until UGC will fail. Contents of accumulator A value and B value will add.
Step-4: DCR B it means decrement by 1.
Step-5: JNZ means jump not equals to zero.
Step-6: It became false, then execute next statement.
ADI 25H means add 25H to (81) 10
(25) 16 = (37) 10
convert decimal value into Hexadecimal.
(118) 10 = (76) 16
Step-7: HLT means halt the program.
Note: We are converting hexadecimal into decimal for only calculation. without conversion also we can solve a problem.