Dogbolt Decompiler Explorer

 https://dogbolt.org/

Dogbolt is an online interactive decompiler explorer. A binary can be uploaded and the decompiled C-like output of multiple decompilers compared. The website collects all uploaded binaries, so be wary of which files to upload. The big advantage of the website is having so many available decompilers (angr, Binary Ninja, Boomerang, Ghidra, IDA Pro, REC Studio, Reko, RetDec, Snowman). A downside is that no alterations to the decompilation are possible, for example, to provide function signatures.

Godbolt Compiler Explorer

 https://godbolt.org/

The Godbolt compiler explorer allows the user to compile a function and see the corresponding assembly code. It can highlight matching parts in the language and assembly, making it easy to understand how individual expressions are compiled. It supports common languages like C, C++, Go, Rust. It can also work with assembler and LLVM IR.

Another nice feature is, that it can show statistics about assembler code, like needed cycles, instructions, and which resources the instructions need. This uses the LLVM Machine Code Analyzer.

Linux System Call Table

These websites provided an overview of the Linux systemcall interface by listing the syscall numbers, their meanings, and their arguments.

• https://syscalls.mebeim.net/
  • x86, ARM, MIPS, all in 32-bit and 64-bit
  • Kernel versions v4.0 up to current
• https://blog.rchapman.org/posts/Linux_System_Call_Table_for_x86_64/
  • x64
• https://filippo.io/linux-syscall-table/
  • x64
• https://syscalls64.paolostivanin.com/
  • x64
• https://thevivekpandey.github.io/posts/2017-09-25-linux-system-calls.html
  • x64

Online Dis-Assembler

 https://defuse.ca/online-x86-assembler.htm

Website allowing assembly and disassembly of x86 and x64 code.

Online Disassembler

 https://onlinedisassembler.com/odaweb/

The online disassembler can disassemble a wide range of binary formats and platforms. It can disassemble freestanding bytes too. It provides a disassembly view, a graph view, a symbols and a function viewer.

Rappel: Linux Assembly REPL

 https://github.com/yrp604/rappel

Rappel is a pretty janky assembly REPL. It works by creating a shell ELF, starting it under ptrace, then continiously rewriting/running the .text section, while showing the register states. It's maybe half done right now, and supports Linux x86, amd64, armv7 (no thumb), and armv8 at the moment.

x86 Instruction Set

These websites provide reference documentation of the x86 instruction set:

• https://kernfunny.org/x86/ / https://c9x.me/x86/
• https://www.felixcloutier.com/x86/index.html
  • Linked from Godbolt
• http://ref.x86asm.net/coder.html
  • It provides an index for single- and double-byte opcodes based on the bytes