Z80 Assembly 21: Setting Up for a Target System (Screen and Memory)
The Shift to System Programming Up until now, our code has been generic. System programming requires us to stop using symbolic addresses (like PRINT_STRING_ADDR) and start using absolute hardware addresses specific to our target machine. Key System-Specific Areas We Must Identify: Program Load Address (ORG): Where our code starts. Screen Memory: The RAM address where display data is stored. I/O Ports: The addresses for keyboard, sound, and display chips. Setting the Origin (ORG) and Stack (SP) Before execution begins, the assembler must know where in memory the program will be placed. ...