- Applesoft BASIC is a dialect of Microsoft BASIC, developed by Marc McDonald and Ric Weiland, supplied with Apple II computers. It supersedes Integer BASIC and is the BASIC in ROM in all Apple II series computers after the original Apple II model. It is also referred to as FP BASIC (from floating point) because of the Apple DOS command FP used to invoke it, instead of INT for Integer BASIC.
- How the 8086 processor’s microcode engine works (righto.com)
The 8086 microprocessor was a groundbreaking processor introduced by Intel in 1978. It led to the x86 architecture that still dominates desktop and server computing. The 8086 chip uses microcode internally to implement its instruction set. I’ve been reverse-engineering the 8086 from die photos and this blog post discusses how the chip’s microcode engine operated. I’m not going to discuss the contents of the microcode1 or how the microcode controls the rest of the processor here. Instead, I’ll look at how the 8086 decides what microcode to run, steps through the microcode, handles jumps and calls inside the microcode, and physically stores the microcode. It was a challenge to fit the microcode onto the chip with 1978 technology, so Intel used many optimization techniques to reduce the size of the microcode.