Art of Assembly Language, 1st Edition

6.6. 6.6 Floating Point Arithmetic

When the 8086 CPU first appeared in the late 1970s, semiconductor technology was not to the point where Intel could put floating point instructions directly on the 8086 CPU. Therefore, it devised a scheme whereby it could use a second chip to perform the floating point calculations — the floating point unit (or FPU).^[121] It released its original floating point chip, the 8087, in 1980. This particular FPU worked with the 8086, 8088, 80186, and 80188 CPUs. When Intel introduced the 80286 CPU, it released a redesigned 80287 FPU chip to accompany it. Although the 80287 was compatible with the 80386 CPU, Intel designed a better FPU, the 80387, for use in 80386 systems. The 80486 CPU was the first Intel CPU to include ...