Should I Learn x86-64 Assembly or Focus on C/C++ for Reverse Engineering?

C is extremely useful because decompilers often present something close to C, and understanding that reconstructed code helps you follow the program’s higher-level logic. However, decompiled output is only an interpretation. When types, control flow, optimization, or compiler transformations make the output confusing, you need assembly to verify what the machine is actually doing. Optimized and vectorized code can be difficult, so being comfortable switching between C and assembly is the practical approach.

Assembly is important when debugging existing software, stepping through instructions, examining calling conventions, and understanding behavior that a decompiler cannot represent exactly. C and C++ are also valuable, especially for recognizing common compiler patterns and writing your own analysis or debugging tools. You don’t have to choose one language: learn enough C/C++ to understand program structure and enough x86-64 assembly to validate the low-level details.

Learn both, but you don’t need to master every instruction before starting. Your 8086 background gives you the basic mental model, and x86-64 mainly adds more registers, a different calling convention, and newer instruction sets. Focus on registers, memory access, stack frames, function calls, control flow, and how data is passed between functions. Then practice with real binaries and debuggers.