Question

Assembly Analysis:

Please write pseudocode/c code/python code or just describe what is this recursive function doing.

Thank you!

Dump of assembler code for function func4:

   0x0000000000401015 <+0>: push %r12

   0x0000000000401017 <+2>: push %rbp

   0x0000000000401018 <+3>: push %rbx

   0x0000000000401019 <+4>: mov %edi,%ebx

   0x000000000040101b <+6>: test %edi,%edi

   0x000000000040101d <+8>: jle 0x401041 <func4+44>

   0x000000000040101f <+10>: mov %esi,%ebp

   0x0000000000401021 <+12>: cmp $0x1,%edi

   0x0000000000401024 <+15>: je 0x401048 <func4+51>

   0x0000000000401026 <+17>: lea -0x1(%rdi),%edi

   0x0000000000401029 <+20>: callq 0x401015 <func4>

   0x000000000040102e <+25>: lea (%rax,%rbp,1),%r12d

   0x0000000000401032 <+29>: lea -0x2(%rbx),%edi

   0x0000000000401035 <+32>: mov %ebp,%esi

   0x0000000000401037 <+34>: callq 0x401015 <func4>

   0x000000000040103c <+39>: add %r12d,%eax

   0x000000000040103f <+42>: jmp 0x40104a <func4+53>

   0x0000000000401041 <+44>: mov $0x0,%eax

   0x0000000000401046 <+49>: jmp 0x40104a <func4+53>

   0x0000000000401048 <+51>: mov %esi,%eax

   0x000000000040104a <+53>: pop %rbx

   0x000000000040104b <+54>: pop %rbp

   0x000000000040104c <+55>: pop %r12

   0x000000000040104e <+57>: retq

Answer 1

put the stack
ebi = edx
if edi is not zero
    if edi is one: then eax=ebp.
                   rearrange the stack
                   return.
    else: edi = -0x1(rbx)
          func4
          r12d = eax
          edi = -0x2(rbx)
          esi = ebp
          func4
          eax = rax+r12+ebp
          rearrange the stack and return.
else
    ebp=0
    eax=ebp
    return