Part 2. “Itanic”: Intel’s Attempt to Deviate from X86
content by Xing Chen
Ironically, the first and the only attempt to deviate from the X86 architecture is by Intel itself, one of the two leading members of the X86 Ecosystem Advisory Group, without success.
Do you still remember the Itanium processor, the IA-64 instruction set, the famous EPIC, which stands for Explicitly Parallel Instruction Computing? Actually, it is the “reinvent” of the VLIW instruction set, which is the short for Very Long Instruction Word. The idea of VLIW is that when the CPU decoder receives the very long instruction word, it knows already the instructions in the word can be executed in parallel, and it doesn’t need to further spend time and energy to find the parallelism between them.
Initially, Intel targeted to make the IA-64 (Itanium) the future 64-bit instruction set, it had no intention to evolve the old 32-bit version X86 to 64-bit; and to be backward compatible, an “Emulation” solution has been carved out to run X86 32-bit applications on IA-64, the Itanium CPU.
While Intel was busy with the IA-64 Itanium, it was AMD who had advanced the X86 architecture to AMD64. After it had realized that IA-64 is a dead end, Intel followed AMD and developed the Xeon using the AMD64 extension, which is also known as 64-bit version X86, the X86–64 for short.
Intel’s first attempt to deviate from the X86 architecture ended with the “Itanic” CPU, its production continued further into a few years but always with very very low market share.
Ever since then, no further attempt to deviated from the X86 has been made, so far so good……
