user: 这段汇编代码用C语言表示是什么样的?

```asm
<v4lconvert_rotate90_yuv420>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  mov    %rdi,-0x28(%rbp)
  mov    %rsi,-0x30(%rbp)
  mov    %edx,-0x34(%rbp)
  mov    %ecx,-0x38(%rbp)
  movl   $0x0,-0x10(%rbp)
  jmp    L63
L67:
  movl   $0x0,-0x14(%rbp)
  jmp    L5
L61:
  mov    -0x34(%rbp),%eax
  sub    -0x14(%rbp),%eax
  sub    $0x1,%eax
  imul   -0x38(%rbp),%eax
  mov    %eax,%edx
  mov    -0x10(%rbp),%eax
  add    %edx,%eax
  mov    %eax,-0x4(%rbp)
  mov    -0x4(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  lea    (%rdx,%rax,1),%rcx
  mov    -0x30(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x30(%rbp)
  movzbl (%rcx),%edx
  mov    %dl,(%rax)
  addl   $0x1,-0x14(%rbp)
L5:
  mov    -0x14(%rbp),%eax
  cmp    -0x34(%rbp),%eax
  jl     L61
  addl   $0x1,-0x10(%rbp)
L63:
  mov    -0x10(%rbp),%eax
  cmp    -0x38(%rbp),%eax
  jl     L67
  mov    -0x38(%rbp),%eax
  imul   -0x34(%rbp),%eax
  cltq
  add    %rax,-0x28(%rbp)
  mov    -0x34(%rbp),%eax
  mov    %eax,%edx
  shr    $0x1f,%edx
  add    %edx,%eax
  sar    %eax
  mov    %eax,-0x34(%rbp)
  mov    -0x38(%rbp),%eax
  mov    %eax,%edx
  shr    $0x1f,%edx
  add    %edx,%eax
  sar    %eax
  mov    %eax,-0x38(%rbp)
  movl   $0x0,-0x10(%rbp)
  jmp    L11
L2:
  movl   $0x0,-0x14(%rbp)
  jmp    L94
L79:
  mov    -0x34(%rbp),%eax
  sub    -0x14(%rbp),%eax
  sub    $0x1,%eax
  imul   -0x38(%rbp),%eax
  mov    %eax,%edx
  mov    -0x10(%rbp),%eax
  add    %edx,%eax
  mov    %eax,-0x8(%rbp)
  mov    -0x8(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  lea    (%rdx,%rax,1),%rcx
  mov    -0x30(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x30(%rbp)
  movzbl (%rcx),%edx
  mov    %dl,(%rax)
  addl   $0x1,-0x14(%rbp)
L94:
  mov    -0x14(%rbp),%eax
  cmp    -0x34(%rbp),%eax
  jl     L79
  addl   $0x1,-0x10(%rbp)
L11:
  mov    -0x10(%rbp),%eax
  cmp    -0x38(%rbp),%eax
  jl     L2
  mov    -0x38(%rbp),%eax
  imul   -0x34(%rbp),%eax
  cltq
  add    %rax,-0x28(%rbp)
  movl   $0x0,-0x10(%rbp)
  jmp    L48
L69:
  movl   $0x0,-0x14(%rbp)
  jmp    L35
L88:
  mov    -0x34(%rbp),%eax
  sub    -0x14(%rbp),%eax
  sub    $0x1,%eax
  imul   -0x38(%rbp),%eax
  mov    %eax,%edx
  mov    -0x10(%rbp),%eax
  add    %edx,%eax
  mov    %eax,-0xc(%rbp)
  mov    -0xc(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x28(%rbp),%rax
  lea    (%rdx,%rax,1),%rcx
  mov    -0x30(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x30(%rbp)
  movzbl (%rcx),%edx
  mov    %dl,(%rax)
  addl   $0x1,-0x14(%rbp)
L35:
  mov    -0x14(%rbp),%eax
  cmp    -0x34(%rbp),%eax
  jl     L88
  addl   $0x1,-0x10(%rbp)
L48:
  mov    -0x10(%rbp),%eax
  cmp    -0x38(%rbp),%eax
  jl     L69
  nop
  nop
  pop    %rbp
  ret
```

assistant: ```c
void v4lconvert_rotate90_yuv420(const unsigned char *src, unsigned char *dst, int destwidth, int destheight) {
  int x, y;
  for (y = 0; y < destheight; y++)
    for (x = 0; x < destwidth; x++) {
      int offset = (destwidth - x - 1) * destheight + y;
      *dst++ = src[offset];
    }
  src += destheight * destwidth;
  destwidth /= 2;
  destheight /= 2;
  for (y = 0; y < destheight; y++)
    for (x = 0; x < destwidth; x++) {
      int offset = (destwidth - x - 1) * destheight + y;
      *dst++ = src[offset];
    }
  src += destheight * destwidth;
  for (y = 0; y < destheight; y++)
    for (x = 0; x < destwidth; x++) {
      int offset = (destwidth - x - 1) * destheight + y;
      *dst++ = src[offset];
    }
}
```