user: 请从给定的汇编指令推导出C源代码：

```asm
<shift>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  mov    %edi,%edx
  mov    %esi,%eax
  mov    %dl,-0x4(%rbp)
  mov    %al,-0x8(%rbp)
  movsbl -0x8(%rbp),%eax
  cmp    $0xb,%eax
  ja     L196
  mov    %eax,%eax
  lea    0x0(,%rax,4),%rdx
  lea    D8(%rip),%rax
  mov    (%rdx,%rax,1),%eax
  cltq
  lea    D8(%rip),%rdx
  add    %rdx,%rax
  notrack jmp *%rax
  movzbl -0x4(%rbp),%eax
  add    $0x1,%eax
  jmp    L26
  movzbl -0x4(%rbp),%edx
  mov    $0x67,%ecx
  mov    %ecx,%eax
  imul   %dl
  shr    $0x8,%ax
  sar    %al
  sar    $0x7,%dl
  sub    %edx,%eax
  and    $0x1,%eax
  test   %al,%al
  je     L71
  movzbl -0x4(%rbp),%eax
  add    $0x7,%eax
  jmp    L26
L71:
  movzbl -0x4(%rbp),%eax
  add    $0x6,%eax
  jmp    L26
  movzbl -0x4(%rbp),%edx
  mov    $0x67,%ecx
  mov    %ecx,%eax
  imul   %dl
  shr    $0x8,%ax
  sar    %al
  sar    $0x7,%dl
  sub    %edx,%eax
  and    $0x1,%eax
  test   %al,%al
  je     L28
  movzbl -0x4(%rbp),%eax
  add    $0x6,%eax
  jmp    L26
L28:
  movzbl -0x4(%rbp),%eax
  add    $0x5,%eax
  jmp    L26
  movzbl -0x4(%rbp),%eax
  add    $0xa,%eax
  jmp    L26
  movzbl -0x4(%rbp),%edx
  mov    $0x67,%ecx
  mov    %ecx,%eax
  imul   %dl
  shr    $0x8,%ax
  sar    %al
  sar    $0x7,%dl
  sub    %edx,%eax
  and    $0x1,%eax
  test   %al,%al
  je     L87
  movzbl -0x4(%rbp),%eax
  add    $0x5,%eax
  jmp    L26
L87:
  movzbl -0x4(%rbp),%eax
  add    $0x4,%eax
  jmp    L26
  movzbl -0x4(%rbp),%edx
  mov    $0x67,%ecx
  mov    %ecx,%eax
  imul   %dl
  shr    $0x8,%ax
  sar    %al
  sar    $0x7,%dl
  sub    %edx,%eax
  and    $0x1,%eax
  test   %al,%al
  je     L162
  movzbl -0x4(%rbp),%eax
  add    $0x4,%eax
  jmp    L26
L162:
  movzbl -0x4(%rbp),%eax
  add    $0x3,%eax
  jmp    L26
  movzbl -0x4(%rbp),%eax
  sub    $0x1,%eax
  jmp    L26
  movzbl -0x4(%rbp),%edx
  mov    $0x67,%ecx
  mov    %ecx,%eax
  imul   %dl
  shr    $0x8,%ax
  sar    %al
  sar    $0x7,%dl
  sub    %edx,%eax
  and    $0x1,%eax
  test   %al,%al
  je     L130
  movzbl -0x4(%rbp),%eax
  sub    $0x6,%eax
  jmp    L26
L130:
  movzbl -0x4(%rbp),%eax
  sub    $0x7,%eax
  jmp    L26
  movzbl -0x4(%rbp),%edx
  mov    $0x67,%ecx
  mov    %ecx,%eax
  imul   %dl
  shr    $0x8,%ax
  sar    %al
  sar    $0x7,%dl
  sub    %edx,%eax
  and    $0x1,%eax
  test   %al,%al
  je     L124
  movzbl -0x4(%rbp),%eax
  sub    $0x5,%eax
  jmp    L26
L124:
  movzbl -0x4(%rbp),%eax
  sub    $0x6,%eax
  jmp    L26
  movzbl -0x4(%rbp),%eax
  sub    $0xa,%eax
  jmp    L26
  movzbl -0x4(%rbp),%edx
  mov    $0x67,%ecx
  mov    %ecx,%eax
  imul   %dl
  shr    $0x8,%ax
  sar    %al
  sar    $0x7,%dl
  sub    %edx,%eax
  and    $0x1,%eax
  test   %al,%al
  je     L227
  movzbl -0x4(%rbp),%eax
  sub    $0x4,%eax
  jmp    L26
L227:
  movzbl -0x4(%rbp),%eax
  sub    $0x5,%eax
  jmp    L26
  movzbl -0x4(%rbp),%edx
  mov    $0x67,%ecx
  mov    %ecx,%eax
  imul   %dl
  shr    $0x8,%ax
  sar    %al
  sar    $0x7,%dl
  sub    %edx,%eax
  and    $0x1,%eax
  test   %al,%al
  je     L199
  movzbl -0x4(%rbp),%eax
  sub    $0x3,%eax
  jmp    L26
L199:
  movzbl -0x4(%rbp),%eax
  sub    $0x4,%eax
  jmp    L26
L196:
  movzbl -0x4(%rbp),%eax
L26:
  pop    %rbp
  ret
```

assistant: ```c
char shift(char cell, char dir) {
  switch (dir) {
  case 0:
    return cell + 1;
  case 1:
    if ((cell / 5) % 2)
      return cell + 7;
    else
      return cell + 6;
  case 2:
    if ((cell / 5) % 2)
      return cell + 6;
    else
      return cell + 5;
  case 3:
    return cell + 10;
  case 4:
    if ((cell / 5) % 2)
      return cell + 5;
    else
      return cell + 4;
  case 5:
    if ((cell / 5) % 2)
      return cell + 4;
    else
      return cell + 3;
  case 6:
    return cell - 1;
  case 7:
    if ((cell / 5) % 2)
      return cell - 6;
    else
      return cell - 7;
  case 8:
    if ((cell / 5) % 2)
      return cell - 5;
    else
      return cell - 6;
  case 9:
    return cell - 10;
  case 10:
    if ((cell / 5) % 2)
      return cell - 4;
    else
      return cell - 5;
  case 11:
    if ((cell / 5) % 2)
      return cell - 3;
    else
      return cell - 4;
  default:
    return cell;
  }
}
```