user: 下面的汇编指令对应的C源代码是什么:

```asm
<search_for_fpart>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x20,%rsp
  mov    %rdi,-0x18(%rbp)
  mov    %esi,-0x1c(%rbp)
  mov    %edx,-0x20(%rbp)
  movl   $0x0,-0xc(%rbp)
  mov    -0x20(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%eax
  mov    %eax,%edi
  call   <get_size@plt>
  mov    %eax,-0x8(%rbp)
  cmpl   $0x0,-0x20(%rbp)
  je     L55
  mov    -0x20(%rbp),%edx
  mov    -0x8(%rbp),%eax
  add    %edx,%eax
  cltq
  shl    $0x2,%rax
  lea    -0x4(%rax),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%eax
  jmp    L69
L55:
  mov    $0x0,%eax
L69:
  mov    %eax,-0x4(%rbp)
  mov    -0x1c(%rbp),%eax
  cmp    -0x4(%rbp),%eax
  jge    L82
  mov    -0x20(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%eax
  mov    %eax,%edi
  call   <get_use_bit@plt>
  test   %eax,%eax
  jne    L82
  mov    -0x8(%rbp),%edx
  mov    -0x20(%rbp),%ecx
  mov    -0x18(%rbp),%rax
  mov    %ecx,%esi
  mov    %rax,%rdi
  call   <is_last_block@plt>
  test   %eax,%eax
  jne    L82
  mov    -0x20(%rbp),%eax
  jmp    L137
L82:
  mov    -0x20(%rbp),%edx
  mov    -0x18(%rbp),%rax
  mov    %edx,%esi
  mov    %rax,%rdi
  call   <get_f_link@plt>
  mov    %eax,-0xc(%rbp)
  jmp    L106
L129:
  mov    -0xc(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%eax
  mov    %eax,%edi
  call   <get_size@plt>
  mov    %eax,-0x8(%rbp)
  cmpl   $0x0,-0xc(%rbp)
  je     L37
  mov    -0xc(%rbp),%edx
  mov    -0x8(%rbp),%eax
  add    %edx,%eax
  cltq
  shl    $0x2,%rax
  lea    -0x4(%rax),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%eax
  jmp    L12
L37:
  mov    $0x0,%eax
L12:
  mov    %eax,-0x4(%rbp)
  mov    -0x1c(%rbp),%eax
  cmp    -0x4(%rbp),%eax
  jge    L88
  mov    -0xc(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%eax
  mov    %eax,%edi
  call   <get_use_bit@plt>
  test   %eax,%eax
  jne    L88
  mov    -0x8(%rbp),%edx
  mov    -0xc(%rbp),%ecx
  mov    -0x18(%rbp),%rax
  mov    %ecx,%esi
  mov    %rax,%rdi
  call   <is_last_block@plt>
  test   %eax,%eax
  jne    L88
  mov    -0xc(%rbp),%eax
  jmp    L137
L88:
  mov    -0xc(%rbp),%edx
  mov    -0x18(%rbp),%rax
  mov    %edx,%esi
  mov    %rax,%rdi
  call   <get_f_link@plt>
  mov    %eax,-0xc(%rbp)
L106:
  mov    -0x20(%rbp),%eax
  cmp    -0xc(%rbp),%eax
  jne    L129
  mov    $0xffffffff,%eax
L137:
  leave
  ret
```

assistant: ```c
int search_for_fpart(const int *mem, int k, int fpart) {
  int npart = 0;
  int psize = get_size(mem[fpart]);
  int fpart_size = (0 == fpart) ? 0 : mem[fpart + psize - 1];
  if ((fpart_size >= (k + 1)) && !get_use_bit(mem[fpart]) && !is_last_block(mem, fpart, psize)) {
    return fpart;
  } else {
    npart = get_f_link(mem, fpart);
    while (fpart != npart) {
      psize = get_size(mem[npart]);
      fpart_size = (0 == npart) ? 0 : mem[npart + psize - 1];
      if ((fpart_size >= (k + 1)) && !get_use_bit(mem[npart]) && !is_last_block(mem, npart, psize)) {
        return npart;
      }
      npart = get_f_link(mem, npart);
    }
  }
  return -1;
}
```