(gdb) disassemble a
Dump of assembler code for function a():
   0x0000000000400cd0 <+0>: xor    %eax,%eax
   0x0000000000400cd2 <+2>: mov    $0x6020c0,%edx
   0x0000000000400cd7 <+7>: nopw   0x0(%rax,%rax,1)
   0x0000000000400ce0 <+16>:    movzbl (%rdx),%ecx
   0x0000000000400ce3 <+19>:    add    $0x1,%rdx
   0x0000000000400ce7 <+23>:    add    %ecx,%eax
   0x0000000000400ce9 <+25>:    cmp    $0x6020c6,%rdx
   0x0000000000400cf0 <+32>:    jne    0x400ce0 <a()+16>
   0x0000000000400cf2 <+34>:    repz retq
End of assembler dump.
(gdb) disassemble b
Dump of assembler code for function b():
   0x0000000000400ca0 <+0>: xor    %eax,%eax
   0x0000000000400ca2 <+2>: mov    $0x6020c0,%edx
   0x0000000000400ca7 <+7>: nopw   0x0(%rax,%rax,1)
   0x0000000000400cb0 <+16>:    movzbl (%rdx),%ecx
   0x0000000000400cb3 <+19>:    add    $0x1,%rdx
   0x0000000000400cb7 <+23>:    add    %ecx,%eax
   0x0000000000400cb9 <+25>:    cmp    $0x6020c6,%rdx
   0x0000000000400cc0 <+32>:    jne    0x400cb0 <b()+16>
   0x0000000000400cc2 <+34>:    repz retq
End of assembler dump.