Computer History

Inside the Intel 8087 chip: floating-point addition and subtraction

Ken Shirriff reverse-engineers the Intel 8087 floating-point coprocessor's microcode and circuitry to explain exactly how it performs addition and subtraction, including exponent alignment, normalization, rounding and the many special cases for infinities, denormals, unnormals and pseudo-zeros.

Blog post · Hardware · Reverse Engineering · Computer History