The MOS Technology 6502 is a popular microprocessor that was widely used in the 1970s and 1980s. It was used in a variety of computers, including the Apple II, Commodore 64, and Atari 2600. This guide will provide an introduction to the history and syntax of the 6502 assembly language, along with examples of how to write programs in it. Additionally, we will explore the best applications for this programming language.
History of MOS Technology 6502
The MOS Technology 6502 was developed by Chuck Peddle and Bill Mensch in the mid-1970s. It was designed as a low-cost alternative to other microprocessors on the market at the time. The 6502 was first used in the KIM-1 computer kit, which was sold by MOS Technology in 1976. This computer kit was designed for hobbyists and was marketed as an affordable way to learn about computers and programming.
The popularity of the 6502 grew rapidly, and it was soon used in a variety of computers, including the Apple II, Commodore 64, and Atari 2600. The 6502 was known for its simplicity, speed, and low cost. Its success paved the way for other low-cost microprocessors, such as the Zilog Z80 and the Motorola 6800.
Syntax of MOS Technology 6502
The 6502 assembly language is a low-level programming language that is used to write programs for the MOS Technology 6502 microprocessor. The syntax of this programming language is relatively simple and easy to learn. Here is an example of a simple program written in 6502 assembly language:
```
LDX #$00 ; Load X register with the value 0
LDY #$05 ; Load Y register with the value 5
LOOP: STA $8000,X ; Store the value of X in memory location 8000
INX ; Increment the X register by 1
CPY #$00 ; Compare the value in Y register with 0
BNE LOOP ; Branch to the LOOP label if Y is not equal to 0
```
This program will store the values 0, 1, 2, 3, and 4 in memory locations 8000 to 8004.
Applications of MOS Technology 6502
The MOS Technology 6502 is no longer used in modern computers, but it is still used in some embedded systems and retro computers. Additionally, the 6502 assembly language is still used by enthusiasts and hobbyists who enjoy programming vintage computers.
One popular application of the 6502 is in the creation of retro games. Many classic video games, such as Super Mario Bros. and The Legend of Zelda, were written in 6502 assembly language. The simplicity and speed of the 6502 made it a popular choice for game developers in the 1980s.
Conclusion
The MOS Technology 6502 and its assembly language played a significant role in the development of personal computers and video games. Although it is no longer used in modern computers, it still holds a special place in the hearts of retro computing enthusiasts. With its simple syntax and low cost, the 6502 assembly language is a great language to learn for anyone interested in retro computing or embedded systems.