user: What would the C source look like for the assembly code provided here?

```asm
<mirror_x>:
  endbr64
  movzbl (%rdi),%ecx
  mov    %ecx,%esi
  mov    %ecx,%edx
  and    $0x1,%edx
  shr    $0x7,%sil
  shl    $0x7,%edx
  movzbl %sil,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shl    $0x5,%esi
  and    $0x40,%esi
  or     %esi,%edx
  lea    0x0(,%rcx,8),%esi
  and    $0x20,%esi
  or     %esi,%edx
  lea    (%rcx,%rcx,1),%esi
  and    $0x10,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    %esi
  and    $0x8,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    $0x5,%ecx
  shr    $0x3,%esi
  and    $0x2,%ecx
  and    $0x4,%esi
  or     %esi,%edx
  or     %ecx,%edx
  movzbl 0x1(%rdi),%ecx
  mov    %dl,(%rdi)
  mov    %ecx,%esi
  mov    %ecx,%edx
  and    $0x1,%edx
  shr    $0x7,%sil
  shl    $0x7,%edx
  movzbl %sil,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shl    $0x5,%esi
  and    $0x40,%esi
  or     %esi,%edx
  lea    0x0(,%rcx,8),%esi
  and    $0x20,%esi
  or     %esi,%edx
  lea    (%rcx,%rcx,1),%esi
  and    $0x10,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    %esi
  and    $0x8,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    $0x5,%ecx
  shr    $0x3,%esi
  and    $0x2,%ecx
  and    $0x4,%esi
  or     %esi,%edx
  or     %ecx,%edx
  movzbl 0x2(%rdi),%ecx
  mov    %dl,0x1(%rdi)
  mov    %ecx,%esi
  mov    %ecx,%edx
  and    $0x1,%edx
  shr    $0x7,%sil
  shl    $0x7,%edx
  movzbl %sil,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shl    $0x5,%esi
  and    $0x40,%esi
  or     %esi,%edx
  lea    0x0(,%rcx,8),%esi
  and    $0x20,%esi
  or     %esi,%edx
  lea    (%rcx,%rcx,1),%esi
  and    $0x10,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    %esi
  and    $0x8,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    $0x5,%ecx
  shr    $0x3,%esi
  and    $0x2,%ecx
  and    $0x4,%esi
  or     %esi,%edx
  or     %ecx,%edx
  movzbl 0x3(%rdi),%ecx
  mov    %dl,0x2(%rdi)
  mov    %ecx,%esi
  mov    %ecx,%edx
  and    $0x1,%edx
  shr    $0x7,%sil
  shl    $0x7,%edx
  movzbl %sil,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shl    $0x5,%esi
  and    $0x40,%esi
  or     %esi,%edx
  lea    0x0(,%rcx,8),%esi
  and    $0x20,%esi
  or     %esi,%edx
  lea    (%rcx,%rcx,1),%esi
  and    $0x10,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    %esi
  and    $0x8,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    $0x5,%ecx
  shr    $0x3,%esi
  and    $0x2,%ecx
  and    $0x4,%esi
  or     %esi,%edx
  or     %ecx,%edx
  movzbl 0x4(%rdi),%ecx
  mov    %dl,0x3(%rdi)
  mov    %ecx,%esi
  mov    %ecx,%edx
  and    $0x1,%edx
  shr    $0x7,%sil
  shl    $0x7,%edx
  movzbl %sil,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shl    $0x5,%esi
  and    $0x40,%esi
  or     %esi,%edx
  lea    0x0(,%rcx,8),%esi
  and    $0x20,%esi
  or     %esi,%edx
  lea    (%rcx,%rcx,1),%esi
  and    $0x10,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    %esi
  and    $0x8,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    $0x3,%esi
  and    $0x4,%esi
  or     %esi,%edx
  shr    $0x5,%ecx
  and    $0x2,%ecx
  or     %ecx,%edx
  movzbl 0x5(%rdi),%ecx
  mov    %dl,0x4(%rdi)
  mov    %ecx,%esi
  mov    %ecx,%edx
  and    $0x1,%edx
  shr    $0x7,%sil
  shl    $0x7,%edx
  movzbl %sil,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shl    $0x5,%esi
  and    $0x40,%esi
  or     %esi,%edx
  lea    0x0(,%rcx,8),%esi
  and    $0x20,%esi
  or     %esi,%edx
  lea    (%rcx,%rcx,1),%esi
  and    $0x10,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    %esi
  and    $0x8,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    $0x5,%ecx
  shr    $0x3,%esi
  and    $0x2,%ecx
  and    $0x4,%esi
  or     %esi,%edx
  or     %ecx,%edx
  movzbl 0x6(%rdi),%ecx
  mov    %dl,0x5(%rdi)
  mov    %ecx,%esi
  mov    %ecx,%edx
  and    $0x1,%edx
  shr    $0x7,%sil
  shl    $0x7,%edx
  movzbl %sil,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shl    $0x5,%esi
  and    $0x40,%esi
  or     %esi,%edx
  lea    0x0(,%rcx,8),%esi
  and    $0x20,%esi
  or     %esi,%edx
  lea    (%rcx,%rcx,1),%esi
  and    $0x10,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    %esi
  and    $0x8,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    $0x5,%ecx
  shr    $0x3,%esi
  and    $0x2,%ecx
  and    $0x4,%esi
  or     %esi,%edx
  or     %ecx,%edx
  movzbl 0x7(%rdi),%ecx
  mov    %dl,0x6(%rdi)
  mov    %ecx,%esi
  mov    %ecx,%edx
  and    $0x1,%edx
  shr    $0x7,%sil
  movzbl %sil,%esi
  shl    $0x7,%edx
  or     %esi,%edx
  mov    %ecx,%esi
  shl    $0x5,%esi
  and    $0x40,%esi
  or     %esi,%edx
  lea    0x0(,%rcx,8),%esi
  and    $0x20,%esi
  or     %esi,%edx
  lea    (%rcx,%rcx,1),%esi
  and    $0x10,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    %esi
  and    $0x8,%esi
  or     %esi,%edx
  mov    %ecx,%esi
  shr    $0x5,%ecx
  shr    $0x3,%esi
  and    $0x2,%ecx
  and    $0x4,%esi
  or     %esi,%edx
  or     %ecx,%edx
  mov    %dl,0x7(%rdi)
  ret
```

assistant: ```c
void mirror_x(unsigned char *bitmap) {
  int c;
  int d;
  int v;
  for (c = 0; c < 8; c++) {
    v = 0;
    for (d = 0; d < 8; d++)
      v |= ((bitmap[c] >> d) & 1) << (7 - d);
    bitmap[c] = v;
  }
}
```