For an old CPU, finding all the valid instructions wasn’t very hard. You simply tried them all. Sure, really old CPUs might make it hard to tell what the instruction did, but once CPUs got illegal ...

This paper presents an instruction set simulator of a 32-bit CPU and explains its use in embedded software development. Interaction of the ISS with transaction level model of a complex peripheral ...

Continuing his reverse-engineering of the Intel 8087, [Ken Shirriff] covers the conditional tests that are implemented in the microcode of this floating point processing unit (FPU). This microcode ...

This paper presents an instruction set simulator of an 8-bit, MCS-51 compatible CPU core, and shows how to use it in embedded software development process; Method to control and debug CPU using ...

When asked about how a central processing unit works, you might say it’s the brain of the computer. It does all the calculations on math and makes logical decisions based on certain outcomes. However, ...