Intel 8087
The Intel 8087, announced in 1980, was the first floating-point coprocessor for the 8086 line of microprocessors. The purpose of the chip was to speed up floating-point arithmetic operations, such as addition, subtraction, multiplication, division, and square root. It also computes transcendental functions such as exponential, logarithmic or trigonometric calculations. The performance enhancements were from approximately 20% to over 500%, depending on the specific application. The 8087 could perform about 50,000 FLOPS using around 2.4 watts.
| General information | |
|---|---|
| Launched | 1980 |
| Marketed by | Intel, IBM |
| Designed by | Intel |
| Common manufacturer(s) | |
| Performance | |
| Max. CPU clock rate | 4 MHz to 10 MHz |
| Architecture and classification | |
| Technology node | 3 μm |
| Instruction set | x87 (coprocessor extension of x86-16) |
| Physical specifications | |
| Transistors |
|
| Package(s) |
|
| History | |
| Predecessor(s) | 8231/8232 |
| Successor(s) | 80287 |
The 8087 was an advanced integrated circuit, pushing the limits of manufacturing technology of the period. Basic operations on the 8087 such as addition and subtraction can take over 100 machine cycles to execute and some instructions exceed 1000 cycles. The chip lacks a hardware multiplier and implements calculations using the CORDIC algorithm.
Sales of the 8087 received a significant boost when a coprocessor socket was included on the 1981 IBM PC motherboard. Development of the 8087 led to the IEEE 754-1985 standard for floating-point arithmetic. The available speed version were 4.77 (5), 8, and 10 MHz. There were later x87 coprocessors for the 80186, 80286, 80386, and 80386SX processors. Starting with the 80486, the later Intel x86 processors did not use a separate floating-point coprocessor; floating-point functions were integrated with the processor.