Reverse-engineering the vintage Intel 8087’s tangent algorithm: more than CORDIC

T1Covered by 1 source · first reported by Raspberry Pi / Arduino / Adafruit at 28 Sept, 13:22 UTC

Ken Shirriff has published another teardown of Intel’s 8087 floating-point coprocessor on righto.com, this time covering the FPTAN tangent instruction. He removed the chip’s lid with a chisel and imaged the die under a microscope, then read the 1648 micro-instructions in the microcode ROM to work…

hardware

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• T1Reverse-engineering the vintage Intel 8087’s tangent algorithm: more than CORDICRaspberry Pi / Arduino / Adafruit28 Sept, 13:22