user: Please show me the C implementation that matches the assembly code listed below:

```asm
<hash_djbx33>:
  endbr64
  mov    %rdi,%rax
  cmp    $0x7,%rsi
  jbe    L42
  lea    -0x8(%rsi),%rdx
  mov    $0x1505,%r8d
  shr    $0x3,%rdx
  lea    0x8(%rdi,%rdx,8),%rcx
  nopl   0x0(%rax)
L40:
  mov    %r8,%rdx
  add    $0x8,%rax
  shl    $0x5,%rdx
  lea    (%rdx,%r8,1),%rdi
  movzbl -0x8(%rax),%edx
  add    %rdi,%rdx
  mov    %rdx,%rdi
  shl    $0x5,%rdi
  add    %rdx,%rdi
  movzbl -0x7(%rax),%edx
  add    %rdi,%rdx
  mov    %rdx,%rdi
  shl    $0x5,%rdi
  add    %rdx,%rdi
  movzbl -0x6(%rax),%edx
  add    %rdi,%rdx
  mov    %rdx,%rdi
  shl    $0x5,%rdi
  add    %rdx,%rdi
  movzbl -0x5(%rax),%edx
  add    %rdi,%rdx
  mov    %rdx,%rdi
  shl    $0x5,%rdi
  add    %rdx,%rdi
  movzbl -0x4(%rax),%edx
  add    %rdi,%rdx
  mov    %rdx,%rdi
  shl    $0x5,%rdi
  add    %rdx,%rdi
  movzbl -0x3(%rax),%edx
  add    %rdi,%rdx
  mov    %rdx,%rdi
  shl    $0x5,%rdi
  add    %rdx,%rdi
  movzbl -0x2(%rax),%edx
  movzbl -0x1(%rax),%r8d
  add    %rdi,%rdx
  mov    %rdx,%rdi
  shl    $0x5,%rdi
  add    %rdi,%rdx
  add    %rdx,%r8
  cmp    %rcx,%rax
  jne    L40
  and    $0x7,%esi
L56:
  cmp    $0x7,%rsi
  ja     L9
  lea    D9(%rip),%rdx
  movslq (%rdx,%rsi,4),%rax
  add    %rdx,%rax
  notrack jmp *%rax
  nopl   (%rax)
  mov    %r8,%rax
  add    $0x1,%rcx
  shl    $0x5,%rax
  add    %r8,%rax
  movzbl -0x1(%rcx),%r8d
  add    %rax,%r8
  mov    %r8,%rax
  add    $0x1,%rcx
  shl    $0x5,%rax
  add    %r8,%rax
  movzbl -0x1(%rcx),%r8d
  add    %rax,%r8
  mov    %r8,%rax
  lea    0x1(%rcx),%rdx
  shl    $0x5,%rax
  add    %r8,%rax
  movzbl (%rcx),%r8d
  add    %rax,%r8
L43:
  mov    %r8,%rax
  lea    0x1(%rdx),%rcx
  shl    $0x5,%rax
  add    %r8,%rax
  movzbl (%rdx),%r8d
  add    %rax,%r8
  mov    %r8,%rax
  lea    0x1(%rcx),%rdx
  shl    $0x5,%rax
  add    %r8,%rax
  movzbl (%rcx),%r8d
  add    %rax,%r8
L10:
  mov    %r8,%rax
  lea    0x1(%rdx),%rcx
  shl    $0x5,%rax
  add    %r8,%rax
  movzbl (%rdx),%r8d
  add    %rax,%r8
  mov    %r8,%rax
  shl    $0x5,%rax
  add    %r8,%rax
  movzbl (%rcx),%r8d
  add    %rax,%r8
L9:
  mov    %r8,%rax
  ret
  nopl   (%rax)
  mov    %rcx,%rdx
  jmp    L43
  nopl   (%rax)
  mov    %rcx,%rdx
  jmp    L10
  nopl   (%rax)
L42:
  mov    %rdi,%rcx
  mov    $0x1505,%r8d
  jmp    L56
```

assistant: ```c
unsigned long hash_djbx33(register unsigned char *key, register size_t len) {
  register unsigned long hash = 5381;
  for (; len >= 8; len -= 8) {
    hash = ((hash << 5) + hash) + *key++;
    hash = ((hash << 5) + hash) + *key++;
    hash = ((hash << 5) + hash) + *key++;
    hash = ((hash << 5) + hash) + *key++;
    hash = ((hash << 5) + hash) + *key++;
    hash = ((hash << 5) + hash) + *key++;
    hash = ((hash << 5) + hash) + *key++;
    hash = ((hash << 5) + hash) + *key++;
  }
  switch (len) {
  case 7:
    hash = ((hash << 5) + hash) + *key++;
  case 6:
    hash = ((hash << 5) + hash) + *key++;
  case 5:
    hash = ((hash << 5) + hash) + *key++;
  case 4:
    hash = ((hash << 5) + hash) + *key++;
  case 3:
    hash = ((hash << 5) + hash) + *key++;
  case 2:
    hash = ((hash << 5) + hash) + *key++;
  case 1:
    hash = ((hash << 5) + hash) + *key++;
    break;
  default:
    break;
  }
  return hash;
}
```