user: 请从给定的汇编指令推导出C源代码:

```asm
<v4lconvert_yuyv_to_bgr24>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  mov    %rdi,-0x28(%rbp)
  mov    %rsi,-0x30(%rbp)
  mov    %edx,-0x34(%rbp)
  mov    %ecx,-0x38(%rbp)
  jmp    L241
L208:
  movl   $0x0,-0x18(%rbp)
  jmp    L196
L162:
  mov    -0x28(%rbp),%rax
  add    $0x1,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,-0x14(%rbp)
  mov    -0x28(%rbp),%rax
  add    $0x3,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,-0x10(%rbp)
  mov    -0x14(%rbp),%eax
  add    $0xffffff80,%eax
  shl    $0x7,%eax
  mov    %eax,%edx
  mov    -0x14(%rbp),%eax
  add    $0xffffff80,%eax
  add    %edx,%eax
  sar    $0x6,%eax
  mov    %eax,-0xc(%rbp)
  mov    -0x14(%rbp),%eax
  add    $0xffffff80,%eax
  lea    (%rax,%rax,1),%edx
  mov    -0x14(%rbp),%eax
  add    $0xffffff80,%eax
  add    %eax,%edx
  mov    -0x10(%rbp),%eax
  add    $0xffffff80,%eax
  shl    $0x2,%eax
  add    %eax,%edx
  mov    -0x10(%rbp),%eax
  add    $0xffffff80,%eax
  add    %eax,%eax
  add    %edx,%eax
  sar    $0x3,%eax
  mov    %eax,-0x8(%rbp)
  mov    -0x10(%rbp),%eax
  add    $0xffffff80,%eax
  lea    (%rax,%rax,1),%edx
  mov    -0x10(%rbp),%eax
  add    $0xffffff80,%eax
  add    %edx,%eax
  sar    %eax
  mov    %eax,-0x4(%rbp)
  mov    -0x28(%rbp),%rax
  movzbl (%rax),%eax
  movzbl %al,%edx
  mov    -0xc(%rbp),%eax
  add    %edx,%eax
  cmp    $0xff,%eax
  jg     L199
  mov    -0x28(%rbp),%rax
  movzbl (%rax),%eax
  movzbl %al,%edx
  mov    -0xc(%rbp),%eax
  add    %edx,%eax
  test   %eax,%eax
  js     L126
  mov    -0x28(%rbp),%rax
  movzbl (%rax),%eax
  mov    -0xc(%rbp),%edx
  add    %edx,%eax
  jmp    L43
L126:
  mov    $0x0,%eax
  jmp    L43
L199:
  mov    $0xffffffff,%eax
L43:
  mov    -0x30(%rbp),%rdx
  lea    0x1(%rdx),%rcx
  mov    %rcx,-0x30(%rbp)
  mov    %al,(%rdx)
  mov    -0x28(%rbp),%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  sub    -0x8(%rbp),%eax
  cmp    $0xff,%eax
  jg     L258
  mov    -0x28(%rbp),%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  sub    -0x8(%rbp),%eax
  test   %eax,%eax
  js     L135
  mov    -0x28(%rbp),%rax
  movzbl (%rax),%eax
  mov    -0x8(%rbp),%edx
  sub    %edx,%eax
  jmp    L263
L135:
  mov    $0x0,%eax
  jmp    L263
L258:
  mov    $0xffffffff,%eax
L263:
  mov    -0x30(%rbp),%rdx
  lea    0x1(%rdx),%rcx
  mov    %rcx,-0x30(%rbp)
  mov    %al,(%rdx)
  mov    -0x28(%rbp),%rax
  movzbl (%rax),%eax
  movzbl %al,%edx
  mov    -0x4(%rbp),%eax
  add    %edx,%eax
  cmp    $0xff,%eax
  jg     L25
  mov    -0x28(%rbp),%rax
  movzbl (%rax),%eax
  movzbl %al,%edx
  mov    -0x4(%rbp),%eax
  add    %edx,%eax
  test   %eax,%eax
  js     L183
  mov    -0x28(%rbp),%rax
  movzbl (%rax),%eax
  mov    -0x4(%rbp),%edx
  add    %edx,%eax
  jmp    L259
L183:
  mov    $0x0,%eax
  jmp    L259
L25:
  mov    $0xffffffff,%eax
L259:
  mov    -0x30(%rbp),%rdx
  lea    0x1(%rdx),%rcx
  mov    %rcx,-0x30(%rbp)
  mov    %al,(%rdx)
  mov    -0x28(%rbp),%rax
  add    $0x2,%rax
  movzbl (%rax),%eax
  movzbl %al,%edx
  mov    -0xc(%rbp),%eax
  add    %edx,%eax
  cmp    $0xff,%eax
  jg     L191
  mov    -0x28(%rbp),%rax
  add    $0x2,%rax
  movzbl (%rax),%eax
  movzbl %al,%edx
  mov    -0xc(%rbp),%eax
  add    %edx,%eax
  test   %eax,%eax
  js     L103
  mov    -0x28(%rbp),%rax
  add    $0x2,%rax
  movzbl (%rax),%eax
  mov    -0xc(%rbp),%edx
  add    %edx,%eax
  jmp    L29
L103:
  mov    $0x0,%eax
  jmp    L29
L191:
  mov    $0xffffffff,%eax
L29:
  mov    -0x30(%rbp),%rdx
  lea    0x1(%rdx),%rcx
  mov    %rcx,-0x30(%rbp)
  mov    %al,(%rdx)
  mov    -0x28(%rbp),%rax
  add    $0x2,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  sub    -0x8(%rbp),%eax
  cmp    $0xff,%eax
  jg     L163
  mov    -0x28(%rbp),%rax
  add    $0x2,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  sub    -0x8(%rbp),%eax
  test   %eax,%eax
  js     L213
  mov    -0x28(%rbp),%rax
  add    $0x2,%rax
  movzbl (%rax),%eax
  mov    -0x8(%rbp),%edx
  sub    %edx,%eax
  jmp    L34
L213:
  mov    $0x0,%eax
  jmp    L34
L163:
  mov    $0xffffffff,%eax
L34:
  mov    -0x30(%rbp),%rdx
  lea    0x1(%rdx),%rcx
  mov    %rcx,-0x30(%rbp)
  mov    %al,(%rdx)
  mov    -0x28(%rbp),%rax
  add    $0x2,%rax
  movzbl (%rax),%eax
  movzbl %al,%edx
  mov    -0x4(%rbp),%eax
  add    %edx,%eax
  cmp    $0xff,%eax
  jg     L257
  mov    -0x28(%rbp),%rax
  add    $0x2,%rax
  movzbl (%rax),%eax
  movzbl %al,%edx
  mov    -0x4(%rbp),%eax
  add    %edx,%eax
  test   %eax,%eax
  js     L278
  mov    -0x28(%rbp),%rax
  add    $0x2,%rax
  movzbl (%rax),%eax
  mov    -0x4(%rbp),%edx
  add    %edx,%eax
  jmp    L108
L278:
  mov    $0x0,%eax
  jmp    L108
L257:
  mov    $0xffffffff,%eax
L108:
  mov    -0x30(%rbp),%rdx
  lea    0x1(%rdx),%rcx
  mov    %rcx,-0x30(%rbp)
  mov    %al,(%rdx)
  addq   $0x4,-0x28(%rbp)
  addl   $0x2,-0x18(%rbp)
L196:
  mov    -0x18(%rbp),%eax
  cmp    -0x34(%rbp),%eax
  jl     L162
L241:
  subl   $0x1,-0x38(%rbp)
  cmpl   $0x0,-0x38(%rbp)
  jns    L208
  nop
  nop
  pop    %rbp
  ret
```

assistant: ```c
void v4lconvert_yuyv_to_bgr24(const unsigned char *src, unsigned char *dest, int width, int height) {
  int j;
  while (--height >= 0) {
    for (j = 0; j < width; j += 2) {
      int u = src[1];
      int v = src[3];
      int u1 = (((u - 128) << 7) + (u - 128)) >> 6;
      int rg = (((u - 128) << 1) + (u - 128) + ((v - 128) << 2) + ((v - 128) << 1)) >> 3;
      int v1 = (((v - 128) << 1) + (v - 128)) >> 1;
      *dest++ = (unsigned char)(((src[0] + u1) > 0xFF) ? 0xff : (((src[0] + u1) < 0) ? 0 : (src[0] + u1)));
      *dest++ = (unsigned char)(((src[0] - rg) > 0xFF) ? 0xff : (((src[0] - rg) < 0) ? 0 : (src[0] - rg)));
      *dest++ = (unsigned char)(((src[0] + v1) > 0xFF) ? 0xff : (((src[0] + v1) < 0) ? 0 : (src[0] + v1)));
      *dest++ = (unsigned char)(((src[2] + u1) > 0xFF) ? 0xff : (((src[2] + u1) < 0) ? 0 : (src[2] + u1)));
      *dest++ = (unsigned char)(((src[2] - rg) > 0xFF) ? 0xff : (((src[2] - rg) < 0) ? 0 : (src[2] - rg)));
      *dest++ = (unsigned char)(((src[2] + v1) > 0xFF) ? 0xff : (((src[2] + v1) < 0) ? 0 : (src[2] + v1)));
      src += 4;
    }
  }
}
```