Z80 Assembly 68: Code Portability and the Abstraction Layer
The Challenge of Portability Throughout this series, we encountered system-specific hardware addresses: screen memory (4000H′), keyboard ports (FEH′), and sound chips (`AY-3-8910′). Code written for the ZX Spectrum will not run on an MSX or a CP/M machine without significant modification. Code Portability is the practice of writing code that minimizes these machine-specific differences, allowing the main logic to be compiled for multiple platforms. Method 1: Conditional Assembly The most fundamental technique is Conditional Assembly. The assembler is instructed to include or exclude specific blocks of code based on a platform constant defined at the beginning of the file. ...