Overview

The two largest manufacturers of the microprocessor chips that were used in the early personal computers incorporated the IEEE standard in their design; these were Intel (whose chips were used by IBM PCs and clones) and Motorola (whose 68000 series chips were used by the Apple Macintosh II and the early Sun workstations). Later microprocessors, such as the Sun Sparc, DEC Alpha, and IBM RS/6000 and Power PC, also followed the standard. Even the IBM 390, the successor to the 360/370 series, offers support for the IEEE standard as an alternative to the long-supported hexadecimal format. We shall confine our attention to the Intel microprocessors, since these chips were and still are the most widely used. The total number of individual computers using these chips is conservatively estimated to be in the hundreds of millions.

The original Intel microprocessor was the 8086 chip, announced in 1978. This chip included a central processing unit (CPU) and an arithmetic-logical unit (ALU) but did not support floating point operations. In 1980, Intel announced the 8087 and 8088 chips, which were used in the first IBM PCs. The 8088 was a modification of the 8086. The 8087 was the floating point coprocessor, providing a floating point unit (FPU) on a separate chip from the 8088. The 8087 was revolutionary in a number of respects. It was unprecedented that so much functionality could be provided by such a small chip. Many of the features of the IEEE standard were first implemented on the 8087.