- There are many functions on a scientific or graphing calculator that we are introduced to as high school students that, we are told, just work. You select the function, put in the value that you need to calculate, hit “=” or “ENTER”, and SHABAM! You have the correct answer to some arbitrary number of digits that you are ensured are all 100% accurate.
- Reverse-engineering the ModR/M addressing microcode in the Intel 8086 processor (righto.com)
One interesting aspect of a computer’s instruction set is its addressing modes, how the computer determines the address for a memory access. The Intel 8086 (1978) used the ModR/M byte, a special byte following the opcode, to select the addressing mode.1 The ModR/M byte has persisted into the modern x86 architecture, so it’s interesting to look at its roots and original implementation.