X87 had more than ten implementations, one of which was the Cyrix 6x86
8087 80287 (original) 80387 (and later 287 models) 80486 (or 80487) Cyrix 6x86, Cyrix MII AMD K6 (including K6 II/III) Pentium / Pentium MMX Pentium Pro Pentium II / III Athlon (K7) Athlon 64 (K8) Pentium 4 
