Before revision: 1 Register–Register CISC Variable (8 to 24 bits) Compare and branch Little x86 16, 32, 64(16→32→64) 1978 2 (integer)3 (AVX)4 (FMA4 and VPBLENDVPx) Register–Memory CISC Variable (8086 ~ 80386: variable between 1 and 6 bytes /w MMU + intel SDK, 80486: 2 to 5 bytes with prefix, pentium and onward: 2 to 4 bytes with prefix, x64: 4 bytes prefix, third party x86 emulation: 1 to 15 bytes w/o prefix & MMU .
After revision: v4 (x86-64)1 Register–Register CISC Variable (8 to 24 bits) Compare and branch Little x86 16, 32, 64(16→32→64) 1978 2 (integer)3 (AVX)4 (FMA4 and VPBLENDVPx) Register–Memory CISC Variable (8086 ~ 80386: variable between 1 and 6 bytes /w MMU + intel SDK, 80486: 2 to 5 bytes with prefix, pentium and onward: 2 to 4 bytes with prefix, x64: 4 bytes prefix, third party x86 emulation: 1 to 15 bytes w/o prefix & MMU .