4 ms·
Pretty surprising. So IA64 registers were 65 bit, with the extra bit describing whether the register contains garbage or not. If NaT (Not a Thing) is set, the r
by vardump 10mo ago
Pretty surprising. So IA64 registers were 65 bit, with the extra bit describing whether the register contains garbage or not. If NaT (Not a Thing) is set, the register contents are invalid and that can cause "fun" things to happen...
Not that this matters to anyone anymore. IA64 utterly failed long ago.
- msla 10mo agoIn case someone hasn't heard: https://en.wikipedia.org/wiki/Itanium https://en.wikipedia.org/wiki/Itanium > In 2019, Intel announced that new orders for Itanium would be accepted until January 30, 2020, and shipments would cease by July 29, 2021.[1] This took place on schedule.[9]
- ashleyn 10mo agoThere are modern VLIW architectures. I think Groq uses one. The lessons on what works and what doesn't are worth learning from history.
- addaon 10mo agoA more everyday example is the Hexagon DSP ISA in Qualcomm chips. Four-wide VLIW + SMT.
- bri3d 10mo agoVLIW works for workloads where the compiler can somewhat accurately predict what will be resident in cache. It’s used everywhere in DSP, was common in GPU for awhile, and is present in lots of niche accelerators. It’s a dead end for situations where cache residency is not predictable, like any kind of multitenant general purpose workload.
- vardump 10mo agoI meant narrowly only about IA64. There is sure some lessons learned value.
- 0dyl 10mo agoThe new TI C2000 F29 series of microcontrollers are VLIW
- msla 10mo agoIA64 was EPIC, which, itself, was a "lessons learned" VLIW design, in that it had things like stop bits to explicitly demarcate dependency boundaries so instructions from multiple words could be combined on future hardware with more parallelism, and speculative execution and loads, which, well, see the article on how the speculative loads were a mixed blessing. https://en.wikipedia.org/wiki/Explicitly_parallel_instruction_computing https://en.wikipedia.org/wiki/Explicitly_parallel_instructio...
- kragen 10mo agoIt matters to people designing new hardware and maybe new virtual machine instruction sets.
- nottorp 10mo agoOr to people caring about their software working on more than just Chrome. ... oh wait, on more than x86(64).