Foundations of Linux Debugging, Disassembling, and Reversing: Analyze Binary Code, Understand Stack Memory Usage, and Reconstruct C/C++ Code with Intel x64

© The Author(s), under exclusive license to APress Media, LLC, part of Springer Nature 2023

D. VostokovFoundations of Linux Debugging, Disassembling, and Reversinghttps://doi.org/10.1007/978-1-4842-9153-5_5

5. Bytes, Words, Double, and Quad Words

Dmitry Vostokov¹  

(1)

Dublin, Ireland

 

Using Hexadecimal Numbers

If we want to use hexadecimal numbers in the C/C++ language, we prefix them with 0x, for example:

a = 12;    // 12_dec

a = 0xC;   // C_hex

In the GDB disassembly output, and when entering commands, numbers are interpreted as decimals by default. If we want a number to be interpreted as hexadecimal, we prefix it with 0x, for example:

mov 12, a

mov 0xC, a

Byte Granularity

Figure 5-1 shows the difference between bytes, words, doublewords, and quadwords ...