Build an OS From Scratch

Design an address decoder that activates a single output line corresponding to a binary address input.

Construct a Random Access Memory (RAM) array by integrating a bank of registers with an address decoder.

Explain the concepts of memory addressing, data buses, and word size in a RAM architecture.

Simulate read and write operations on the constructed RAM chip.

Define the core components of an Instruction Set Architecture (ISA).

Distinguish between opcodes and operands within a binary instruction format.

Explain the three major phases of the Fetch-Decode-Execute cycle.

Design a Program Counter (PC) that can be incremented and loaded with a new address.

Connect the Program Counter and Memory to create the instruction fetch portion of the datapath.

Connect the Register File, ALU, and associated data buses to create the execution portion of the datapath.

Design the logic to parse a binary instruction into its constituent parts (opcode, register specifiers, etc.).

Design the combinational logic that maps opcodes to the static control signals for the ALU and memory.

Design the sequential logic to sequence the control signals required for a complete fetch-decode-execute cycle.

Simulate the 'Fetch' phase of an instruction cycle, tracing the program counter and memory interaction.

Simulate the 'Decode' phase, observing the control unit generating signals from an instruction.

Simulate the 'Execute' phase for an arithmetic instruction, tracing data flow through the ALU and back to a register.

Map C language Boolean operators (&&, ||, !) to their corresponding hardware logic gates.

Translate a basic arithmetic task (e.g., R0 = R1 + R2) into its binary machine code.

Trace the execution of a pre-written conditional branching binary program to visualize loops on the simulated CPU.

Translate basic assembly language mnemonics (e.g., ADD, LOAD, JMP) into binary machine code.

Visualize how C variables map to specific physical RAM addresses in the simulated hardware.

Explain how C pointers translate to memory address manipulation in assembly and machine code.

Simulate the contiguous memory allocation and layout of a C struct within the simulated RAM.

Trace the full execution of a pointer dereference operation through the simulated CPU and Memory.

Explain the concept of memory-mapped Input/Output (I/O).

Interface a simulated keyboard input buffer to the computer's memory architecture.

Interface a simulated pixel-based display to a specific segment of memory (video RAM).

Write a machine language program to draw a static pattern on the simulated screen by directly manipulating video RAM.

Write a machine language program that continuously polls the keyboard and stores the scan code of the last key pressed.

Write a machine language program that implements a simple 'echo' functionality by reading from the keyboard buffer and writing to the screen.

Combine keyboard input and screen output to create a simple interactive program, such as moving a single pixel or character on the screen.