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

```asm
<vp8cx_horizontal_line_3_5_scale_c>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  mov    %rdi,-0x28(%rbp)
  mov    %esi,-0x2c(%rbp)
  mov    %rdx,-0x38(%rbp)
  mov    %ecx,-0x30(%rbp)
  mov    -0x38(%rbp),%rax
  mov    %rax,-0x10(%rbp)
  mov    -0x28(%rbp),%rax
  mov    %rax,-0x8(%rbp)
  movl   $0x0,-0x20(%rbp)
  jmp    L4
L8:
  mov    -0x8(%rbp),%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,-0x1c(%rbp)
  mov    -0x8(%rbp),%rax
  add    $0x1,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,-0x18(%rbp)
  mov    -0x1c(%rbp),%eax
  mov    %eax,%edx
  mov    -0x10(%rbp),%rax
  mov    %dl,(%rax)
  mov    -0x1c(%rbp),%eax
  imul   $0x66,%eax,%edx
  mov    -0x18(%rbp),%eax
  imul   $0x9a,%eax,%eax
  add    %edx,%eax
  sub    $0xffffff80,%eax
  shr    $0x8,%eax
  mov    %eax,%edx
  mov    -0x10(%rbp),%rax
  add    $0x1,%rax
  mov    %dl,(%rax)
  mov    -0x8(%rbp),%rax
  add    $0x2,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,-0x14(%rbp)
  mov    -0x18(%rbp),%eax
  imul   $0xcd,%eax,%edx
  mov    -0x14(%rbp),%eax
  imul   $0x33,%eax,%eax
  add    %edx,%eax
  sub    $0xffffff80,%eax
  shr    $0x8,%eax
  mov    %eax,%edx
  mov    -0x10(%rbp),%rax
  add    $0x2,%rax
  mov    %dl,(%rax)
  mov    -0x18(%rbp),%eax
  imul   $0x33,%eax,%edx
  mov    -0x14(%rbp),%eax
  imul   $0xcd,%eax,%eax
  add    %edx,%eax
  sub    $0xffffff80,%eax
  shr    $0x8,%eax
  mov    %eax,%edx
  mov    -0x10(%rbp),%rax
  add    $0x3,%rax
  mov    %dl,(%rax)
  mov    -0x8(%rbp),%rax
  add    $0x3,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,-0x1c(%rbp)
  mov    -0x14(%rbp),%eax
  imul   $0x9a,%eax,%edx
  mov    -0x1c(%rbp),%eax
  imul   $0x66,%eax,%eax
  add    %edx,%eax
  sub    $0xffffff80,%eax
  shr    $0x8,%eax
  mov    %eax,%edx
  mov    -0x10(%rbp),%rax
  add    $0x4,%rax
  mov    %dl,(%rax)
  addq   $0x3,-0x8(%rbp)
  addq   $0x5,-0x10(%rbp)
  addl   $0x3,-0x20(%rbp)
L4:
  mov    -0x2c(%rbp),%eax
  sub    $0x3,%eax
  cmp    %eax,-0x20(%rbp)
  jb     L8
  mov    -0x8(%rbp),%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,-0x1c(%rbp)
  mov    -0x8(%rbp),%rax
  add    $0x1,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,-0x18(%rbp)
  mov    -0x1c(%rbp),%eax
  mov    %eax,%edx
  mov    -0x10(%rbp),%rax
  mov    %dl,(%rax)
  mov    -0x1c(%rbp),%eax
  imul   $0x66,%eax,%edx
  mov    -0x18(%rbp),%eax
  imul   $0x9a,%eax,%eax
  add    %edx,%eax
  sub    $0xffffff80,%eax
  shr    $0x8,%eax
  mov    %eax,%edx
  mov    -0x10(%rbp),%rax
  add    $0x1,%rax
  mov    %dl,(%rax)
  mov    -0x8(%rbp),%rax
  add    $0x2,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,-0x14(%rbp)
  mov    -0x18(%rbp),%eax
  imul   $0xcd,%eax,%edx
  mov    -0x14(%rbp),%eax
  imul   $0x33,%eax,%eax
  add    %edx,%eax
  sub    $0xffffff80,%eax
  shr    $0x8,%eax
  mov    %eax,%edx
  mov    -0x10(%rbp),%rax
  add    $0x2,%rax
  mov    %dl,(%rax)
  mov    -0x18(%rbp),%eax
  imul   $0x33,%eax,%edx
  mov    -0x14(%rbp),%eax
  imul   $0xcd,%eax,%eax
  add    %edx,%eax
  sub    $0xffffff80,%eax
  shr    $0x8,%eax
  mov    %eax,%edx
  mov    -0x10(%rbp),%rax
  add    $0x3,%rax
  mov    %dl,(%rax)
  mov    -0x10(%rbp),%rax
  add    $0x4,%rax
  mov    -0x14(%rbp),%edx
  mov    %dl,(%rax)
  nop
  pop    %rbp
  ret
```

assistant: ```c
void vp8cx_horizontal_line_3_5_scale_c(const unsigned char *source, unsigned int source_width, unsigned char *dest, unsigned int dest_width) {
  unsigned int i;
  unsigned int a, b, c;
  unsigned char *des = dest;
  const unsigned char *src = source;
  (void)dest_width;
  for (i = 0; i < source_width - 3; i += 3) {
    a = src[0];
    b = src[1];
    des[0] = (unsigned char)(a);
    des[1] = (unsigned char)((a * 102 + 154 * b + 128) >> 8);
    c = src[2];
    des[2] = (unsigned char)((b * 205 + c * 51 + 128) >> 8);
    des[3] = (unsigned char)((b * 51 + c * 205 + 128) >> 8);
    a = src[3];
    des[4] = (unsigned char)((c * 154 + a * 102 + 128) >> 8);
    src += 3;
    des += 5;
  }
  a = src[0];
  b = src[1];
  des[0] = (unsigned char)(a);
  des[1] = (unsigned char)((a * 102 + 154 * b + 128) >> 8);
  c = src[2];
  des[2] = (unsigned char)((b * 205 + c * 51 + 128) >> 8);
  des[3] = (unsigned char)((b * 51 + c * 205 + 128) >> 8);
  des[4] = (unsigned char)(c);
}
```