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Can someone please help me to understand, why "b8", "bb" and "cd" is getting added in machine code though I am moving only 1, 10 and 80 to registers.

user@ubuntu:~/Documents/MyCode$ objdump -d shell1 -M intel

shell1:     file format elf32-i386


Disassembly of section .text:

08048060 <_start>:
 8048060:       **b8** 01 00 00 00          mov    eax,0x1
 8048065:       **bb** 0a 00 00 00          mov    ebx,0xa
 804806a:       **cd** 80                   int    0x80

Thanks,

Jester
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WebEye
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1 Answers1

1

Those are operation codes in hexadecimal (opcodes).

INT is 0xcd

mov is 0xb8, 0xbb, (and some more)

2501
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