Unicorn CPU emulator framework (ARM, AArch64, M68K, Mips, Sparc, X86)
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Peter Maydell 31013d5a8f target/arm: Fix SMLAD incorrect setting of Q bit
The SMLAD instruction is supposed to:
* signed multiply Rn[15:0] * Rm[15:0]
* signed multiply Rn[31:16] * Rm[31:16]
* perform a signed addition of the products and Ra
* set Rd to the low 32 bits of the theoretical
infinite-precision result
* set the Q flag if the sign-extension of Rd
would differ from the infinite-precision result
(ie on overflow)

Our current implementation doesn't quite do this, though: it performs
an addition of the products setting Q on overflow, and then it adds
Ra, again possibly setting Q. This sometimes incorrectly sets Q when
the architecturally mandated only-check-for-overflow-once algorithm
does not. For instance:
r1 = 0x80008000; r2 = 0x80008000; r3 = 0xffffffff
smlad r0, r1, r2, r3
This is (-32768 * -32768) + (-32768 * -32768) - 1

The products are both 0x4000_0000, so when added together as 32-bit
signed numbers they overflow (and QEMU sets Q), but because the
addition of Ra == -1 brings the total back down to 0x7fff_ffff
there is no overflow for the complete operation and setting Q is
incorrect.

Fix this edge case by resorting to 64-bit arithmetic for the
case where we need to add three values together.

Backports commit 5288145d716338ace0f83e3ff05c4d07715bb4f4
2021-03-01 19:58:39 -05:00
bindings python: handle UC_ERR_TIMEOUT, so sample_x86.py behaves like sample_x86.c 2020-01-14 09:53:10 -05:00
docs docs: we no longer requires python2 in building 2020-01-14 09:07:44 -05:00
include Timeout error (#1173) 2020-01-14 09:42:57 -05:00
msvc msvc: Define CONFIG_TCG 2019-01-30 13:52:30 -05:00
qemu target/arm: Fix SMLAD incorrect setting of Q bit 2021-03-01 19:58:39 -05:00
samples Timeout error (#1173) 2020-01-14 09:42:57 -05:00
tests Tests, fixes on third platform. (#1168) 2020-01-14 09:45:55 -05:00
.appveyor.yml MSYS test (#852) 2017-06-25 10:11:35 +08:00
.gitignore target/riscv: Initial introduction of the RISC-V target 2019-03-08 21:46:10 -05:00
.travis.yml use new travis osx image and brew (#935) 2018-01-05 10:29:49 +08:00
AUTHORS.TXT import 2015-08-21 15:04:50 +08:00
Brewfile Update Brewfile 2017-09-30 17:36:44 +07:00
ChangeLog update ChangeLog 2017-04-20 13:28:02 +08:00
config.mk Fix document file extension 2016-08-08 17:33:49 +09:00
COPYING import 2015-08-21 15:04:50 +08:00
COPYING.LGPL2 LGPL2 for all header files under include/unicorn/ 2017-12-16 10:08:42 +08:00
COPYING_GLIB glib_compat: add COPYING_GLIB 2016-12-27 10:15:08 +08:00
CREDITS.TXT Adding Philippe Antoine to CREDITS 2018-10-06 04:50:10 -04:00
install-cmocka-linux.sh Start moving examples in S files (#851) 2017-06-25 10:14:22 +08:00
list.c callback to count number of instructions in uc_emu_start() should be executed first. fix #727 2017-06-16 13:22:38 +08:00
make.sh remove broken iOS builds (#1109) 2019-08-08 20:09:05 -04:00
Makefile uc: Restore armeb target 2019-04-19 15:29:25 -04:00
msvc.bat add msvc.bat 2017-04-21 15:35:40 +08:00
pkgconfig.mk bump extra version to 2 2017-04-21 15:30:40 +08:00
README.md add Clojure 2017-12-23 00:32:33 +08:00
uc.c Timeout error (#1173) 2020-01-14 09:42:57 -05:00
windows_export.bat Make the call out to visual studio extremely resilient 2017-01-02 03:32:48 -08:00

Unicorn Engine

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Build Status Build status

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.