Version 12 of bytecode

Updated 2014-05-25 20:03:37 by pooryorick

Tcl bytecode is the instruction set targeted by TAL

Documentation

$tcl_traceExec

Reading

Wikipedia

See Also

Parsing, Bytecodes and Execution

Playing bytecode

Brute force meets Goedel

Proc to bytecodes: when, how does it happen

Commands affecting Bytecoding

The anatomy of a bytecoded command

Why compile to bytecode

bytecode dissasembly and/or examination

script compilation

Description

DKF 2003-01-06 (from .NET) :

... the current Tcl bytecodes are defined at a level that is meaningful to Tcl, not at a level that virtually any other bytecode operates at; very few bytecodes have an opcode for "increment-hash-entry-and-fire-attached-traces"! Given that, you're either just producing another language reimplementation (like Jacl) or you're taking on the hard task of defining how to go from Tcl to the fairly-common low-level register-based bytecode engines that so many other languages use. Which would be nice and useful, but is a really huge (and definitely complex and deep) task...

Why Byte-Coded Commands Can Be Faster Than C-Coded Commands

Byte-Coded commands are sometimes faster than commands implemented in an external language like C. MS, Tcl Chatroom, 2013-12-31, offered these reasons:

1. Byte-coded commands access local variables directly, whereas commands implemented in C have to resolve them at runtime.
2. Dispatch to an external command is slower than dispatch to a byte-coded command
3. Often, only the most frequently-used code-paths of a command are byte-coded, and corner cases fall back to the C implementation of the command.

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