user: 请从给定的汇编指令推导出C源代码：

```asm
<flip_D1>:
  endbr64
  movabs $0xfefefefefefe000,%rax
  push   %r14
  movabs $0x10101010101000,%r14
  push   %r13
  movabs $0x1000000000000000,%r13
  push   %r12
  mov    %rsi,%r12
  push   %rbp
  mov    %rdi,%rbp
  and    %r14,%r12
  movabs $0x101010101010,%rdi
  and    %rbp,%rdi
  or     %rax,%r12
  push   %rbx
  mov    %rsi,%rbx
  mov    %rdi,%rax
  shl    $0x8,%rax
  add    %rax,%r12
  and    %r13,%r12
  jne    L84
L59:
  movabs $0x40201000000,%rdi
  mov    %rbx,%rax
  movabs $0x8040200000000,%r14
  movabs $0xff7fbfc00000000,%rdx
  movabs $0x1000000000000000,%r13
  and    %rbp,%rdi
  and    %r14,%rax
  or     %rdx,%rax
  mov    %rdi,%rdx
  shl    $0x9,%rdx
  add    %rdx,%rax
  test   %r13,%rax
  jne    L36
L85:
  movabs $0x408000000000,%rdi
  mov    %rbx,%rax
  movabs $0x20400000000000,%r14
  movabs $0xfdf800000000000,%rdx
  movabs $0x1000000000000000,%r13
  and    %rbp,%rdi
  and    %r14,%rax
  or     %rdx,%rax
  mov    %rdi,%rdx
  shl    $0x7,%rdx
  add    %rdx,%rax
  test   %r13,%rax
  jne    L74
L6:
  movabs $0x700000000000000,%rdi
  and    %rbp,%rdi
  lea    (%rbx,%rdi,2),%rax
  bt     $0x3c,%rax
  jb     L3
L56:
  movabs $0x2000000000000000,%rax
  add    %rax,%rbx
  movabs $0xc000000000000000,%rax
  and    %rbp,%rbx
  and    %rax,%rbx
  je     L46
  movabs $0xe000000000000000,%rax
  add    %rbx,%rax
  or     %rax,%r12
L46:
  pop    %rbx
  mov    %r12,%rax
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  ret
  nopw   0x0(%rax,%rax,1)
L84:
  call   <last_bit@plt>
  mov    $0x2,%edx
  mov    %eax,%ecx
  shl    %cl,%rdx
  sub    %rdx,%r13
  and    %r14,%r13
  mov    %r13,%r12
  jmp    L59
  nopl   (%rax)
L3:
  call   <last_bit@plt>
  mov    $0x2,%edx
  mov    %eax,%ecx
  movabs $0x1000000000000000,%rax
  shl    %cl,%rdx
  sub    %rdx,%rax
  or     %rax,%r12
  jmp    L56
  nopl   0x0(%rax)
L74:
  call   <last_bit@plt>
  mov    $0x2,%edx
  mov    %eax,%ecx
  shl    %cl,%rdx
  sub    %rdx,%r13
  and    %r14,%r13
  or     %r13,%r12
  jmp    L6
  nopl   (%rax)
L36:
  call   <last_bit@plt>
  mov    $0x2,%edx
  mov    %eax,%ecx
  shl    %cl,%rdx
  sub    %rdx,%r13
  and    %r14,%r13
  or     %r13,%r12
  jmp    L85
```

assistant: ```c
unsigned long long flip_D1(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 & 0X0000101010101010ULL;
  opp_discs = (discs_opponent & 0X0010101010101000ULL) | 0X0FEFEFEFEFEFE000ULL;
  r = ((my_discs << 8) + opp_discs) & 0X1000000000000000ULL;
  if (r != 0) {
    flipped |= (0X1000000000000000ULL - (0X2ULL << last_bit(my_discs))) & 0X0010101010101000ULL;
  }
  my_discs = discs_player & 0X0000040201000000ULL;
  opp_discs = (discs_opponent & 0X0008040200000000ULL) | 0X0FF7FBFC00000000ULL;
  r = ((my_discs << 9) + opp_discs) & 0X1000000000000000ULL;
  if (r != 0) {
    flipped |= (0X1000000000000000ULL - (0X2ULL << last_bit(my_discs))) & 0X0008040200000000ULL;
  }
  my_discs = discs_player & 0X0000408000000000ULL;
  opp_discs = (discs_opponent & 0X0020400000000000ULL) | 0X0FDF800000000000ULL;
  r = ((my_discs << 7) + opp_discs) & 0X1000000000000000ULL;
  if (r != 0) {
    flipped |= (0X1000000000000000ULL - (0X2ULL << last_bit(my_discs))) & 0X0020400000000000ULL;
  }
  my_discs = discs_player & 0X0700000000000000ULL;
  r = ((my_discs << 1) + discs_opponent) & 0X1000000000000000ULL;
  if (r != 0) {
    flipped |= 0X1000000000000000ULL - (0X2ULL << last_bit(my_discs));
  }
  my_discs = discs_player & 0XC000000000000000ULL;
  r = (discs_opponent + 0X2000000000000000ULL) & my_discs;
  if (r != 0) {
    flipped |= (r - 1) & 0XE000000000000000ULL;
  }
  return flipped;
}
```