In this program we will see how to find the factorial of a number.
Write 8085 Assembly language program to find the factorial of an 8-bit number.
In 8085, there is no direct instruction to perform multiplication. We need to perform repetitive addition to get the result of the multiplication. In each step we are decreasing the value of B and multiply with the previous value of B. We are repeating these steps until B reaches 1. and B – 1 to 0. Thus the factorial is generated.
|F000||21, 00, 80|| ||LXI H, 8000H||Load the number|
|F003||46|| ||MOV B,M||Take number from memory to B|
|F004||16, 01|| ||MVI D, 01H||Set D to 01H|
|F006||CD, 10, F0||FACT||CALL MUL||Call multiplication|
|F009||05|| ||DCR B||Decrease B by 1|
|F00A||C2, 06, F0|| ||JNZ FACT||If Z = 0, jump to Fact|
|F00D||23|| ||INX H||Point to next location|
|F00E||72|| ||MOV M,D||Store result in memory|
|F00F||76|| ||HLT||Terminate the program|
|F010||58||MUL||MOV E,B||Load B to E|
|F011||AF|| ||XRA A||Clear accumulator to store result|
|F012||82||ML||ADD D||Add D to A|
|F013||1D|| ||DCR E||Decrement E|
|F014||C2, 12, F0|| ||JNZ ML||If Z = 0, jump to ML|
|F017||57|| ||MOV D,A||Transfer contents of A to D|
|F018||C9|| ||RET||Return result|