# nanocore | Afaan Bilal | Knowledge Base | Instagit

NanoCore 8-bit CPU emulator in Rust

GitHub Stars: 262

Repository: https://github.com/afaanbilal/nanocore

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## Articles

### [How the NanoCore CPU Implements the Fetch-Decode-Execute Cycle](/afaanbilal/nanocore/describe-fetch-decode-execute-cycle-as-implemented-in-nanocore-cpu)

Explore the fetch-decode-execute cycle in the NanoCore CPU. Learn how this 8-bit processor reads, decodes, and executes instructions efficiently using pattern matching and updates the program counter.

- Tags: internals
- Published: 2026-02-23

### [NanoCore CPU `update_zn_flags` Method: Implementation and Usage Guide](/afaanbilal/nanocore/what-is-purpose-and-implementation-of-update-zn-flags-method-within-cpu-struct)

Explore the nanocore CPU update_zn_flags method. Understand its implementation and purpose for synchronizing Zero and Negative status flags in your 8-bit CPU emulator. Learn how it evaluates operation results.

- Tags: how-to-guide
- Published: 2026-02-23

### [How to Implement Common Loop Structures in NanoCore Assembly: 3 Complete Examples](/afaanbilal/nanocore/provide-examples-of-how-to-implement-common-loop-structures-in-nanocore-assembly)

Master NanoCore assembly loops using Zero flag and conditional jumps. Explore 3 complete examples to control iteration flow efficiently in your 8-bit projects.

- Tags: how-to-guide
- Published: 2026-02-23

### [Error Handling Mechanisms for Stack Overflow and Stack Underflow in NanoCore](/afaanbilal/nanocore/what-are-error-handling-mechanisms-for-stack-overflow-and-stack-underflow-in-nanocore)

Discover NanoCore's robust error handling for stack overflow and underflow. Learn how it protects your emulator with precise pointer checks and typed emulator errors before critical instructions.

- Tags: deep-dive
- Published: 2026-02-23

### [How the STR Instruction Stores Register Data to Memory in NanoCore](/afaanbilal/nanocore/how-is-str-instruction-used-to-store-data-from-register-to-memory-address)

Learn how the STR instruction in NanoCore stores register data to memory. Explore register-indirect storage and its 256-byte address space functionality for efficient data management.

- Tags: internals
- Published: 2026-02-23

### [How the PRINT Instruction Outputs Characters and Strings to the Console in NanoCore](/afaanbilal/nanocore/how-does-print-instruction-output-characters-or-strings-to-console)

Discover how the PRINT instruction in NanoCore outputs characters and strings to the console converting bytes to ASCII and buffering output.

- Tags: internals
- Published: 2026-02-23

### [How the CMP Instruction Works in NanoCore: Flag Effects and Implementation](/afaanbilal/nanocore/how-does-cmp-compare-instruction-function-and-what-flags-does-it-affect)

Learn how the CMP instruction in NanoCore works. Discover its flag effects (Z and N) and how it enables conditional branching for efficient code execution.

- Tags: internals
- Published: 2026-02-23

### [NanoCore Maximum Program Size: Understanding the 256-Byte Address Space Limit](/afaanbilal/nanocore/what-is-maximum-program-size-that-can-be-loaded-and-executed-by-nanocore-given-its-constraints)

Discover NanoCore's 256-byte address space limit. Learn how this constraint impacts program size and execution. Understand the maximum program size for NanoCore.

- Tags: deep-dive
- Published: 2026-02-23

### [How to Define and Use Data Constants and Strings in NanoCore Assembly](/afaanbilal/nanocore/how-can-i-define-and-use-data-constants-and-strings-in-nanocore-assembly-code)

Learn to define and use data constants and strings in NanoCore assembly with .CONST .DB and .STRING directives. Optimize your code by understanding compile-time constant definition and resolution.

- Tags: how-to-guide
- Published: 2026-02-23

### [Practical Differences Between JMPR and JMP Instructions in NanoCore](/afaanbilal/nanocore/what-are-practical-differences-between-jmpr-and-jmp-instructions-for-program-flow)

Understand the practical differences between JMP and JMPR instructions in NanoCore. Learn how JMPR enables dynamic control flow and supports features like jump tables and function pointers.

- Tags: deep-dive
- Published: 2026-02-23

### [How NanoCore's Wrapping Arithmetic Manages Integer Overflow and Underflow](/afaanbilal/nanocore/how-does-nanocores-wrapping-arithmetic-manage-integer-overflow-and-underflow)

Discover how NanoCore's wrapping arithmetic handles integer overflow and underflow using Rust's `wrapping_*` methods on u8 types for accurate 8-bit CPU emulation.

- Tags: internals
- Published: 2026-02-23

### [Difference Between Logical Shift and Rotate Operations in NanoCore: SHL/SHR vs ROL/ROR](/afaanbilal/nanocore/what-is-difference-between-logical-shift-shl-shr-and-rotate-rol-ror-bitwise-operations-in-nanocore)

Understand the key differences between logical shift SHL SHR and rotate ROL ROR bitwise operations in NanoCore Learn how bits are handled in each to choose the right operation for your needs.

- Tags: deep-dive
- Published: 2026-02-23

### [How NanoCore's Two-Pass Assembler Resolves Labels and Constants](/afaanbilal/nanocore/explain-two-pass-assembler-process-in-nanocore-for-label-and-constant-resolution)

Understand NanoCore's two-pass assembler for efficient label and constant resolution. Learn how it resolves symbolic names to numeric values for bytecode generation.

- Tags: internals
- Published: 2026-02-23

### [How NanoCore Handles Its 256-Byte Memory Constraint and Addressing Architecture](/afaanbilal/nanocore/how-does-nanocore-handle-256-byte-memory-constraint-and-addressing)

Discover how NanoCore manages its 256-byte memory limit using u8 addresses, a fixed RAM array, and wrapping arithmetic. Learn about its addressing architecture.

- Tags: deep-dive
- Published: 2026-02-23