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Raymond Chen recently posted a ten-part introduction to the ia64 architecture. Rapidly teaching me that while I might be able to write a brainfuck to perl compiler in a few minutes, there's no way in a million years that I'll ever be able to write a good compiler that targets ia64.
- Part 1: Warming up
- Part 2: Instruction encoding, templates, and stops
- Part 3: The Windows calling convention, how parameters are passed
- Part 3b: How does spilling actually work?
- Part 4: The Windows calling convention, leaf functions
- Part 5: The GP register, calling functions, and function pointers
- Part 6: Calculating conditionals
- Part 7: Speculative loads
- Part 8: Advanced loads
- Part 9: Counted loops and loop pipelining
- Part 10: Register rotation
The Itanium is a 64-bit EPIC architecture. EPIC stands for Explicitly Parallel Instruction Computing, a design in which work is offloaded from the processor to the compiler. For example, the compiler decides which operations can be safely performed in parallel and which memory fetches can be productively speculated. This relieves the processor from having to make these decisions on the fly, thereby allowing it to focus on the real work of processing.
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New crypt. See /usr/news/crypt.
(Score: 3, Insightful) by Grishnakh on Sunday August 09 2015, @01:37AM
It might have worked too, if it weren't for AMD making x86-64 the mass-market option and thus redirecting much of the compiler talent away from what became a niche architecture. There just was never enough ia64 volume to attract enough devs to work on VLIW compiler design.
Oh please, Itanic was doomed from the start. Itanic systems were horrifically expensive, and aimed at competing with high-end Unix server hardware; they weren't remotely affordable. Why would compiler writers bother with them, unless they're being paid by Intel to do so? If there was a problem with compiler talent, that's Intel's fault for not hiring them in the Itanic compiler team. You're not going to get volunteers to work on something like that, nor are you going to even get commercial developers (say, at Microsoft) to spend much time with it, because they'd rather target the much, much, much, much larger market that is regular PCs and servers running x86 ISA.
(Score: 0) by Anonymous Coward on Sunday August 09 2015, @02:12AM
Big companies just aren't good at doing that kind of research. They are good at adding incremental features to their products, and knocking off features in competitor's products that they can test out in the lab.
Usually what happens is that this kind of research is conducted at several universities, until someone comes up with a promising prototype, publishes a big paper and gets hired away. But this cycle happens at academic speeds (slow), not IT industry speeds (fast). AMD made sure that Intel wouldn't get all the time in the world to get it right, as some other poster pointed out.
(Score: 0) by Anonymous Coward on Sunday August 09 2015, @02:15AM
At the time that itanium was conceived only the lowliest of servers ran x86. Anybody doing data-center work was running RISC systems. The strategic marketing group boffed it. Even then itanium was over a decade ahead of any x86 implementation of high-available functions like memory scrubbers, ECC on cache, ECC on i/o lines and lockstep execution across CPUs.