Re:How to use 1000 registers (1979) [pdf]
by meanonme on Saturday September 29, 2018 @01:45AM
(#18098890)
If you created a runtime virtual machine these days, I wouldn't use stacks or registers... address virtual/virtualized memory directly and let the CPU &| compiler || LLVM sort out register placement... registers are basically another layer in the storage hierarchy, from registers/L0 file all the way down to tape, or eww, hard copy.
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Re:How to use 1000 registers (1979) [pdf]
by ajross on Saturday September 29, 2018 @08:58AM
(#18100088)
That's the way JVM and .NET work. Dalvik moved the other direction and has explicit registers. Honestly the distinction is mostly a wash. The representations are essentially 1:1, any reasonable optimizer will be able to move stuff around regardless of whether it's a "register" or "local variable".
Re:How to use 1000 registers (1979) [pdf]
by FartyMcFarter on Saturday September 29, 2018 @11:44AM
(#18100987)
Why not go all the way with this idea and pretend everything is a hard copy? Your program's statements would all be printing the result of something into paper, or scanning that paper. And then you just let the compiler and CPU figure out which pieces of paper can be put into registers.
The answer is that this is too cumbersome and hard to deal with. So is memory, in a smaller way - when things are in memory they can be affected by other threads, the outputs of different instructions can overlap, etc etc.
Re:How to use 1000 registers (1979) [pdf]
by ychen306 on Saturday September 29, 2018 @01:50AM
(#18098903)
That would not be a good idea. The amount of analysis effort to analyze something in memory is significantly higher than keeping things in (virtual) registers.
Re:How to use 1000 registers (1979) [pdf]
by kccqzy on Saturday September 29, 2018 @03:12AM
(#18099105)
Sounds like the reverse problem is easier: pretending there are many registers and let the toolchain figure out how to spill them to memory.