Unicorn CPU emulator framework (ARM, AArch64, M68K, Mips, Sparc, X86)
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Emilio G. Cota d3ada2feb5
tcg: allocate TB structs before the corresponding translated code
Allocating an arbitrarily-sized array of tbs results in either
(a) a lot of memory wasted or (b) unnecessary flushes of the code
cache when we run out of TB structs in the array.

An obvious solution would be to just malloc a TB struct when needed,
and keep the TB array as an array of pointers (recall that tb_find_pc()
needs the TB array to run in O(log n)).

Perhaps a better solution, which is implemented in this patch, is to
allocate TB's right before the translated code they describe. This
results in some memory waste due to padding to have code and TBs in
separate cache lines--for instance, I measured 4.7% of padding in the
used portion of code_gen_buffer when booting aarch64 Linux on a
host with 64-byte cache lines. However, it can allow for optimizations
in some host architectures, since TCG backends could safely assume that
the TB and the corresponding translated code are very close to each
other in memory. See this message by rth for a detailed explanation:

https://lists.gnu.org/archive/html/qemu-devel/2017-03/msg05172.html
Subject: Re: GSoC 2017 Proposal: TCG performance enhancements

Backports commit 6e3b2bfd6af488a896f7936e99ef160f8f37e6f2 from qemu
2018-03-03 17:05:49 -05:00
bindings
docs
include util: add cacheinfo 2018-03-03 16:58:28 -05:00
msvc target-m68k: move FPU helpers to fpu_helper.c 2018-03-03 15:04:05 -05:00
qemu tcg: allocate TB structs before the corresponding translated code 2018-03-03 17:05:49 -05:00
samples
tests
.appveyor.yml
.gitignore
.travis.yml
AUTHORS.TXT
Brewfile
ChangeLog
config.mk
COPYING
COPYING.LGPL2
COPYING_GLIB
CREDITS.TXT
install-cmocka-linux.sh
list.c
make.sh
Makefile crypto: introduce new module for computing hash digests 2018-02-17 15:23:17 -05:00
msvc.bat
pkgconfig.mk
README.md
uc.c Move target-* CPU file into a target/ folder 2018-03-01 22:50:58 -05:00
windows_export.bat

Unicorn Engine

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Unicorn is a lightweight, multi-platform, multi-architecture CPU emulator framework based on QEMU.

Unicorn offers some unparalleled features:

  • Multi-architecture: ARM, ARM64 (ARMv8), M68K, MIPS, SPARC, and X86 (16, 32, 64-bit)
  • Clean/simple/lightweight/intuitive architecture-neutral API
  • Implemented in pure C language, with bindings for Crystal, Clojure, Visual Basic, Perl, Rust, Ruby, Python, Java, .NET, Go, Delphi/Free Pascal and Haskell.
  • Native support for Windows & *nix (with Mac OSX, Linux, *BSD & Solaris confirmed)
  • High performance via Just-In-Time compilation
  • Support for fine-grained instrumentation at various levels
  • Thread-safety by design
  • Distributed under free software license GPLv2

Further information is available at http://www.unicorn-engine.org

License

This project is released under the GPL license.

Compilation & Docs

See docs/COMPILE.md file for how to compile and install Unicorn.

More documentation is available in docs/README.md.

Contact

Contact us via mailing list, email or twitter for any questions.

Contribute

If you want to contribute, please pick up something from our Github issues.

We also maintain a list of more challenged problems in a TODO list.

CREDITS.TXT records important contributors of our project.