user: 提供的汇编代码用C语言表示会是什么样子：

```asm
<cvt_420p_to_rgb>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  mov    %edi,-0x34(%rbp)
  mov    %esi,-0x38(%rbp)
  mov    %rdx,-0x40(%rbp)
  mov    %rcx,-0x48(%rbp)
  mov    -0x34(%rbp),%eax
  imul   -0x38(%rbp),%eax
  mov    %eax,-0x18(%rbp)
  mov    -0x34(%rbp),%eax
  imul   -0x38(%rbp),%eax
  mov    %eax,%edx
  mov    %edx,%eax
  add    %eax,%eax
  add    %edx,%eax
  movslq %eax,%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x8(%rbp)
  movl   $0x0,-0x1c(%rbp)
  jmp    L93
L55:
  movl   $0x0,-0x20(%rbp)
  jmp    L97
L76:
  mov    -0x1c(%rbp),%edx
  mov    %edx,%eax
  shl    $0x2,%eax
  add    %edx,%eax
  shl    $0x6,%eax
  movslq %eax,%rdx
  mov    -0x20(%rbp),%eax
  cltq
  add    %rax,%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,-0x14(%rbp)
  mov    -0x1c(%rbp),%eax
  mov    %eax,%edx
  shr    $0x1f,%edx
  add    %edx,%eax
  sar    %eax
  mov    %eax,%edx
  mov    %edx,%eax
  shl    $0x2,%eax
  add    %edx,%eax
  shl    $0x5,%eax
  movslq %eax,%rdx
  mov    -0x20(%rbp),%eax
  mov    %eax,%ecx
  shr    $0x1f,%ecx
  add    %ecx,%eax
  sar    %eax
  cltq
  add    %rax,%rdx
  mov    -0x18(%rbp),%eax
  cltq
  add    %rax,%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,-0x10(%rbp)
  mov    -0x1c(%rbp),%eax
  mov    %eax,%edx
  shr    $0x1f,%edx
  add    %edx,%eax
  sar    %eax
  mov    %eax,%edx
  mov    %edx,%eax
  shl    $0x2,%eax
  add    %edx,%eax
  shl    $0x5,%eax
  movslq %eax,%rdx
  mov    -0x20(%rbp),%eax
  mov    %eax,%ecx
  shr    $0x1f,%ecx
  add    %ecx,%eax
  sar    %eax
  cltq
  add    %rax,%rdx
  mov    -0x18(%rbp),%eax
  cltq
  lea    (%rdx,%rax,1),%rcx
  mov    -0x18(%rbp),%eax
  lea    0x3(%rax),%edx
  test   %eax,%eax
  cmovs  %edx,%eax
  sar    $0x2,%eax
  cltq
  lea    (%rcx,%rax,1),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,-0xc(%rbp)
  addl   $0xffffff80,-0x10(%rbp)
  addl   $0xffffff80,-0xc(%rbp)
  mov    -0x14(%rbp),%edx
  mov    -0xc(%rbp),%eax
  add    %eax,%edx
  mov    -0xc(%rbp),%eax
  imul   $0x67,%eax,%eax
  sar    $0x8,%eax
  add    %edx,%eax
  mov    %eax,-0x2c(%rbp)
  mov    -0x10(%rbp),%eax
  imul   $0x58,%eax,%eax
  sar    $0x8,%eax
  mov    %eax,%ecx
  mov    -0x14(%rbp),%eax
  sub    %ecx,%eax
  mov    %eax,%edx
  mov    -0xc(%rbp),%eax
  imul   $0xb7,%eax,%eax
  sar    $0x8,%eax
  mov    %eax,%ecx
  mov    %edx,%eax
  sub    %ecx,%eax
  mov    %eax,-0x28(%rbp)
  mov    -0x14(%rbp),%edx
  mov    -0x10(%rbp),%eax
  add    %eax,%edx
  mov    -0x10(%rbp),%eax
  imul   $0xc6,%eax,%eax
  sar    $0x8,%eax
  add    %edx,%eax
  mov    %eax,-0x24(%rbp)
  cmpl   $0xff,-0x2c(%rbp)
  jle    L8
  movl   $0xff,-0x2c(%rbp)
L8:
  cmpl   $0xff,-0x28(%rbp)
  jle    L75
  movl   $0xff,-0x28(%rbp)
L75:
  cmpl   $0xff,-0x24(%rbp)
  jle    L19
  movl   $0xff,-0x24(%rbp)
L19:
  cmpl   $0x0,-0x2c(%rbp)
  jns    L42
  movl   $0x0,-0x2c(%rbp)
L42:
  cmpl   $0x0,-0x28(%rbp)
  jns    L5
  movl   $0x0,-0x28(%rbp)
L5:
  cmpl   $0x0,-0x24(%rbp)
  jns    L21
  movl   $0x0,-0x24(%rbp)
L21:
  mov    -0x24(%rbp),%eax
  mov    %eax,%edx
  mov    -0x8(%rbp),%rax
  mov    %dl,(%rax)
  subq   $0x1,-0x8(%rbp)
  mov    -0x2c(%rbp),%eax
  mov    %eax,%edx
  mov    -0x8(%rbp),%rax
  mov    %dl,(%rax)
  subq   $0x1,-0x8(%rbp)
  mov    -0x28(%rbp),%eax
  mov    %eax,%edx
  mov    -0x8(%rbp),%rax
  mov    %dl,(%rax)
  subq   $0x1,-0x8(%rbp)
  addl   $0x1,-0x20(%rbp)
L97:
  mov    -0x20(%rbp),%eax
  cmp    -0x34(%rbp),%eax
  jl     L76
  addl   $0x1,-0x1c(%rbp)
L93:
  mov    -0x1c(%rbp),%eax
  cmp    -0x38(%rbp),%eax
  jl     L55
  nop
  nop
  pop    %rbp
  ret
```

assistant: ```c
void cvt_420p_to_rgb(int width, int height, const unsigned char *src, unsigned char *dst) {
  int r, g, b;
  int rdif, gdif, bdif, y;
  int yy, uu, vv;
  int xoff, yoff;
  int numpix = width * height;
  unsigned char *pout = dst + width * height * 3;
  for (yoff = 0; yoff < height; yoff++) {
    for (xoff = 0; xoff < width; xoff++) {
      yy = *(src + yoff * 320 + xoff);
      uu = *(src + (yoff / 2) * 320 / 2 + xoff / 2 + numpix);
      vv = *(src + (yoff / 2) * 320 / 2 + xoff / 2 + numpix + numpix / 4);
      uu -= 128;
      vv -= 128;
      r = yy + vv + ((vv * 103) >> 8);
      g = yy - ((uu * 88) >> 8) - ((vv * 183) >> 8);
      b = yy + uu + ((uu * 198) >> 8);
      if (r > 255) {
        r = 255;
      }
      if (g > 255) {
        g = 255;
      }
      if (b > 255) {
        b = 255;
      }
      if (r < 0) {
        r = 0;
      }
      if (g < 0) {
        g = 0;
      }
      if (b < 0) {
        b = 0;
      }
      *pout = (unsigned char)b;
      pout--;
      *pout = (unsigned char)r;
      pout--;
      *pout = (unsigned char)g;
      pout--;
    }
  }
}
```