Demonstrate SAP-2 Assembly Language Programming
What is the objective of the SAP-2 Assembly language programing?
How does the program take an input byte from port-2 and determine whether to add or subtract based on the MSB bit?
How is the final result stored in memory address 5000H?
Objective of the SAP-2 Assembly Language Programming
The objective of the SAP-2 Assembly language programming is to take an input byte from port-2, check the Most Significant Bit (MSB) of the input byte. If the MSB bit is 1, add the hexadecimal values 5H and 6H to the input byte; otherwise, subtract 6H from 5H. Finally, store the final result at memory address 5000H.
Understanding the Assembly Language Program
LDA 90H: This instruction loads the value of port 2 input into the accumulator (A).
ANI 80H: If the value in the accumulator (A) is less than 80H, it means that the MSB of the input byte is not 1. In this case, 6H will be subtracted from 5H.
CMP C0H: Compares the value stored in the accumulator (A) with C0H (hexadecimal value for 11000000B). If the MSB of the input byte is 1, the carry flag will be set.
JZ Add: If the MSB of the input byte is 1, the program jumps to the label "Add" to add 5H and 6H to the accumulator (A).
SUB 6H: If the MSB of the input byte is not 1, 6H is subtracted from A.
ADD 5H: Adds 5H to the accumulator (A) if the MSB of the input byte is 1.
ADD 6H: Adds 6H to the accumulator (A).
STA 5000H: Stores the final result at memory address 5000H.
HLT: Stops the execution of the program.