I'm curious why you think there was not effort behind ia64.
I still think ia64 was sunk by the let-the-compiler-do-it tarpit. There were ambivalent aspects such as, at the time, questions of power or chip area. But things like memory latency are just not predictable enough to do strictly in-order pipelines. OoO won.
Had AMD not been around with AMD64, the industry would have had to get it working no matter what, HP and Microsoft were already on the Itanium train, and if production of x86 got slowly replaced by Itanium that was it, Windows and HP-UX would drag the ecosystems into it, and eventually the remaining issues would be sorted out.
The compilers were fine, even if not producing maximally optimized code. Intel’s decision to add x86 compatibility circuitry to the die was probably the fatal one, it slowed everything down; made for terrible comparisons with existing x86 performance and generally signalled a lack of confidence. Something like Rosetta was out of the question, but they could have just had better transitioning tools for those code bases that couldn’t be recompiled easily.
markhahn|1 year ago
I still think ia64 was sunk by the let-the-compiler-do-it tarpit. There were ambivalent aspects such as, at the time, questions of power or chip area. But things like memory latency are just not predictable enough to do strictly in-order pipelines. OoO won.
pjmlp|1 year ago
Had AMD not been around with AMD64, the industry would have had to get it working no matter what, HP and Microsoft were already on the Itanium train, and if production of x86 got slowly replaced by Itanium that was it, Windows and HP-UX would drag the ecosystems into it, and eventually the remaining issues would be sorted out.
Tteriffic|1 year ago