user: Converte this assembly snippet into its equivalent C code:

```asm
<flip_H4>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x30,%rsp
  mov    %rdi,-0x28(%rbp)
  mov    %rsi,-0x30(%rbp)
  movq   $0x0,-0x20(%rbp)
  movabs $0xfc00000000,%rax
  and    -0x28(%rbp),%rax
  mov    %rax,-0x18(%rbp)
  movabs $0x200000000,%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  and    -0x18(%rbp),%rax
  mov    %rax,-0x10(%rbp)
  cmpq   $0x0,-0x10(%rbp)
  je     L2
  mov    -0x10(%rbp),%rax
  lea    -0x1(%rax),%rdx
  movabs $0xfe00000000,%rax
  and    %rdx,%rax
  or     %rax,-0x20(%rbp)
L2:
  mov    -0x28(%rbp),%rax
  and    $0x40810,%eax
  mov    %rax,-0x18(%rbp)
  mov    -0x30(%rbp),%rax
  and    $0x2040800,%eax
  mov    %rax,%rdx
  mov    $0xfdfbf000,%eax
  or     %rdx,%rax
  mov    %rax,-0x8(%rbp)
  mov    -0x18(%rbp),%rax
  shl    $0x7,%rax
  mov    %rax,%rdx
  mov    -0x8(%rbp),%rax
  add    %rax,%rdx
  movabs $0x100000000,%rax
  and    %rdx,%rax
  mov    %rax,-0x10(%rbp)
  cmpq   $0x0,-0x10(%rbp)
  je     L8
  mov    -0x18(%rbp),%rax
  mov    %rax,%rdi
  call   <last_bit@plt>
  mov    $0x2,%edx
  mov    %eax,%ecx
  shl    %cl,%rdx
  movabs $0x100000000,%rax
  sub    %rdx,%rax
  and    $0x2040800,%eax
  or     %rax,-0x20(%rbp)
L8:
  movabs $0x804000000000000,%rax
  and    -0x28(%rbp),%rax
  mov    %rax,-0x18(%rbp)
  movabs $0x4020000000000,%rax
  and    -0x30(%rbp),%rax
  movabs $0x7fbfc0000000000,%rdx
  or     %rdx,%rax
  mov    %rax,-0x8(%rbp)
  movabs $0x20000000000,%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  and    -0x18(%rbp),%rax
  mov    %rax,-0x10(%rbp)
  cmpq   $0x0,-0x10(%rbp)
  je     L49
  mov    -0x10(%rbp),%rax
  lea    -0x1(%rax),%rdx
  movabs $0x4020000000000,%rax
  and    %rdx,%rax
  or     %rax,-0x20(%rbp)
L49:
  mov    -0x28(%rbp),%rax
  and    $0x10101,%eax
  mov    %rax,-0x18(%rbp)
  mov    -0x30(%rbp),%rax
  and    $0x1010100,%eax
  mov    %rax,%rdx
  mov    $0xfefefe00,%eax
  or     %rdx,%rax
  mov    %rax,-0x8(%rbp)
  mov    -0x18(%rbp),%rax
  shl    $0x8,%rax
  mov    %rax,%rdx
  mov    -0x8(%rbp),%rax
  add    %rax,%rdx
  movabs $0x100000000,%rax
  and    %rdx,%rax
  mov    %rax,-0x10(%rbp)
  cmpq   $0x0,-0x10(%rbp)
  je     L3
  mov    -0x18(%rbp),%rax
  mov    %rax,%rdi
  call   <last_bit@plt>
  mov    $0x2,%edx
  mov    %eax,%ecx
  shl    %cl,%rdx
  movabs $0x100000000,%rax
  sub    %rdx,%rax
  and    $0x1010100,%eax
  or     %rax,-0x20(%rbp)
L3:
  movabs $0x101000000000000,%rax
  and    -0x28(%rbp),%rax
  mov    %rax,-0x18(%rbp)
  movabs $0x1010000000000,%rax
  and    -0x30(%rbp),%rax
  movabs $0xfefe0000000000,%rdx
  or     %rdx,%rax
  mov    %rax,-0x8(%rbp)
  movabs $0x10000000000,%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  and    -0x18(%rbp),%rax
  mov    %rax,-0x10(%rbp)
  cmpq   $0x0,-0x10(%rbp)
  je     L33
  mov    -0x10(%rbp),%rax
  lea    -0x1(%rax),%rdx
  movabs $0x1010000000000,%rax
  and    %rdx,%rax
  or     %rax,-0x20(%rbp)
L33:
  mov    -0x20(%rbp),%rax
  leave
  ret
```

assistant: ```c
unsigned long long flip_H4(const unsigned long long discs_player, const unsigned long long discs_opponent) {
  unsigned long long my_discs, opp_discs, r, flipped = 0ULL;
  my_discs = discs_player & 0X000000FC00000000ULL;
  r = (discs_opponent + 0X0000000200000000ULL) & my_discs;
  if (r != 0) {
    flipped |= (r - 1) & 0X000000FE00000000ULL;
  }
  my_discs = discs_player & 0X0000000000040810ULL;
  opp_discs = (discs_opponent & 0X0000000002040800ULL) | 0X00000000FDFBF000ULL;
  r = ((my_discs << 7) + opp_discs) & 0X0000000100000000ULL;
  if (r != 0) {
    flipped |= (0X0000000100000000ULL - (0X2ULL << last_bit(my_discs))) & 0X0000000002040800ULL;
  }
  my_discs = discs_player & 0X0804000000000000ULL;
  opp_discs = (discs_opponent & 0X0004020000000000ULL) | 0X07FBFC0000000000ULL;
  r = (opp_discs + 0X0000020000000000ULL) & my_discs;
  if (r != 0) {
    flipped |= (r - 1) & 0X0004020000000000ULL;
  }
  my_discs = discs_player & 0X0000000000010101ULL;
  opp_discs = (discs_opponent & 0X0000000001010100ULL) | 0X00000000FEFEFE00ULL;
  r = ((my_discs << 8) + opp_discs) & 0X0000000100000000ULL;
  if (r != 0) {
    flipped |= (0X0000000100000000ULL - (0X2ULL << last_bit(my_discs))) & 0X0000000001010100ULL;
  }
  my_discs = discs_player & 0X0101000000000000ULL;
  opp_discs = (discs_opponent & 0X0001010000000000ULL) | 0X00FEFE0000000000ULL;
  r = (opp_discs + 0X0000010000000000ULL) & my_discs;
  if (r != 0) {
    flipped |= (r - 1) & 0X0001010000000000ULL;
  }
  return flipped;
}
```