Here’s a snippet from disassembled output of a simple program with gcc on Linux:

  400478:   ff 15 6a 0b 20 00       callq  *0x200b6a(%rip)        # 600fe8 <__libc_start_main@GLIBC_2.2.5>
  40047e:   f4                      hlt  

• Why is hlt needed here?
  • From my understanding, it is if the program fails to exit and it would then trap. However, in what situations would the program fail to exit like this?
• Where is the definition for __libc_start_main?
  • My understanding is it may be dynamically linked.

I’m compiling code to assembly myself and am in particular curious on how to handle program start-up.