| Category | Program Example | |----------|------------------| | Data transfer | Block of memory copy (no overlap) | | Arithmetic | 16-bit addition (HL + DE → HL) | | Subtraction with borrow | 16-bit subtraction (BC - DE) | | Multiplication | By repeated addition (8-bit × 8-bit → 16-bit) | | Division | Repeated subtraction | | Logical | Bit masking / rotation to check parity | | Counter & delay | 10 ms software delay using register pairs | | BCD | Packed BCD to unpacked | | ASCII | ASCII to binary (subtract 30H) | | Stack | Reverse a string stored in memory using PUSH/POP | | Subroutine call | Factorial using recursion (avoid overflow) | | Interrupt | Simulate RST 7.5 service routine |
This advanced section connects the concepts from the first two parts to build complete, functional systems, which is the ultimate goal of learning microprocessor applications.
Ramesh Gaonkar ’s Microprocessor Architecture, Programming, and Applications with the 8085
How the processor locates data, whether it's immediate, direct, or register-indirect.
Gaonkar simplifies complex program flows by explaining conditional jumps ( JZ , JNZ , JC ) and subroutine calls ( CALL , RET ). He shows how these loops manipulate the Program Counter and Stack Pointer. Interfacing and Peripheral Applications He shows how these loops manipulate the Program
Set if the most significant bit (D7) of the result is 1.
Understanding when data moves is as critical as knowing where it goes. The book explicitly breaks down the roles of control lines ( RD¯modified cap R cap D with bar above WR¯modified cap W cap R with bar above ) and status signals ( S1cap S sub 1 S0cap S sub 0
of memory. Understanding its hardware architecture requires looking closely at its internal register structure, control units, and bus systems. Register Structure
A 16-bit register pointing to the current memory location in the stack. 2. The Flags Register The book explicitly breaks down the roles of
: Copies data from a source location to a destination without modifying the original content (e.g., MOV A, B , MVI M, 20H ).
A 16-bit register tracking the memory address of the next instruction to execute.
The text demonstrates how the Arithmetic Logic Unit (ALU) performs 8-bit additions, subtractions, increments, and decrements. It also covers boolean operations like AND , OR , XOR , and bitwise rotations ( RLC , RRC ). Branching and Machine Control
A 5-bit register that keeps track of the results of operations (Zero, Carry, Sign, Parity, Auxiliary Carry). relying instead on accessible software simulators.
Microprocessor Architecture, Programming and Applications with the 8085
A microprocessor is useless without real-world connections. Gaonkar dedicates the latter half of the 2014 edition to interfacing techniques, transforming the theoretical chip into a functional system controller. Memory Interfacing
It includes practical lab exercises that do not require expensive hardware trainers, relying instead on accessible software simulators.