| Bckgrnd2 - JITs and Portability |
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| • | “Portable”
languages e.g., Java |
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| • | Does
not compile directly to CPU native code |
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| • | Interpretive
execution of common bytecodes on VMs |
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| • | Speed
problem （1/10 ～ 1/100 vs. optim. native code) |
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| • | Just-In-Time
compiler to the rescue |
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| • | Rather
old idea: Smalltalk, etc. |
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| • | Compile
bytecode into native code at runtime |
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| • | 1/2 ～ 1/10
vs. optim. native code |
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| • | Sun,
MS, IBM, Symantec, Fujitsu, etc., vigorously |
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| developing
“the best” Java JIT. |
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