Intel 8087

bias generation circuit

Inside the die of Intel’s 8087 coprocessor chip, root of modern floating point (righto.com) Looking inside the Intel 8087, an early floating point chip, I noticed an interesting feature on the die: the substrate bias generation circuit. In this article I explain how this circuit is implemented, using analog and digital circuitry to create a negative voltage.

So God made the vault and separated the water under the vault from the water above it. And it was so. Genesis 1:7 NIV

Extracting ROM constants from the 8087 math coprocessor’s die (righto.com) Intel introduced the 8087 chip in 1980 to improve floating-point performance on the 8086 and 8088 processors, and it was used with the original IBM PC. Since early microprocessors operated only on integers, arithmetic with floating-point numbers was slow and transcendental operations such as arctangent or logarithms were even worse. Adding the 8087 co-processor chip to a system made floating-point operations up to 100 times faster.