user: 请将这段汇编代码片段转换成等效的C代码:

```asm
<plotEllipse>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x30,%rsp
  mov    %edi,-0x24(%rbp)
  mov    %esi,-0x28(%rbp)
  mov    %edx,-0x2c(%rbp)
  mov    %ecx,-0x30(%rbp)
  mov    -0x2c(%rbp),%eax
  neg    %eax
  mov    %eax,-0x18(%rbp)
  movl   $0x0,-0x14(%rbp)
  mov    -0x30(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x30(%rbp),%eax
  cltq
  imul   %rdx,%rax
  mov    %rax,-0x8(%rbp)
  mov    -0x18(%rbp),%eax
  cltq
  mov    -0x8(%rbp),%rdx
  lea    (%rdx,%rdx,1),%rcx
  mov    -0x18(%rbp),%edx
  movslq %edx,%rdx
  add    %rcx,%rdx
  imul   %rax,%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x10(%rbp)
L25:
  mov    -0x28(%rbp),%edx
  mov    -0x14(%rbp),%eax
  add    %eax,%edx
  mov    -0x24(%rbp),%eax
  sub    -0x18(%rbp),%eax
  mov    %edx,%esi
  mov    %eax,%edi
  call   <setPixel@plt>
  mov    -0x28(%rbp),%edx
  mov    -0x14(%rbp),%eax
  add    %eax,%edx
  mov    -0x24(%rbp),%ecx
  mov    -0x18(%rbp),%eax
  add    %ecx,%eax
  mov    %edx,%esi
  mov    %eax,%edi
  call   <setPixel@plt>
  mov    -0x28(%rbp),%eax
  sub    -0x14(%rbp),%eax
  mov    -0x24(%rbp),%ecx
  mov    -0x18(%rbp),%edx
  add    %ecx,%edx
  mov    %eax,%esi
  mov    %edx,%edi
  call   <setPixel@plt>
  mov    -0x28(%rbp),%eax
  sub    -0x14(%rbp),%eax
  mov    %eax,%edx
  mov    -0x24(%rbp),%eax
  sub    -0x18(%rbp),%eax
  mov    %edx,%esi
  mov    %eax,%edi
  call   <setPixel@plt>
  mov    -0x10(%rbp),%rax
  add    %rax,%rax
  mov    %rax,-0x8(%rbp)
  mov    -0x18(%rbp),%eax
  add    %eax,%eax
  add    $0x1,%eax
  movslq %eax,%rdx
  mov    -0x30(%rbp),%eax
  cltq
  imul   %rax,%rdx
  mov    -0x30(%rbp),%eax
  cltq
  imul   %rdx,%rax
  cmp    %rax,-0x8(%rbp)
  jl     L27
  addl   $0x1,-0x18(%rbp)
  mov    -0x18(%rbp),%eax
  add    %eax,%eax
  add    $0x1,%eax
  movslq %eax,%rdx
  mov    -0x30(%rbp),%eax
  cltq
  imul   %rax,%rdx
  mov    -0x30(%rbp),%eax
  cltq
  imul   %rdx,%rax
  add    %rax,-0x10(%rbp)
L27:
  mov    -0x14(%rbp),%eax
  add    %eax,%eax
  add    $0x1,%eax
  movslq %eax,%rdx
  mov    -0x2c(%rbp),%eax
  cltq
  imul   %rax,%rdx
  mov    -0x2c(%rbp),%eax
  cltq
  imul   %rdx,%rax
  cmp    %rax,-0x8(%rbp)
  jg     L43
  addl   $0x1,-0x14(%rbp)
  mov    -0x14(%rbp),%eax
  add    %eax,%eax
  add    $0x1,%eax
  movslq %eax,%rdx
  mov    -0x2c(%rbp),%eax
  cltq
  imul   %rax,%rdx
  mov    -0x2c(%rbp),%eax
  cltq
  imul   %rdx,%rax
  add    %rax,-0x10(%rbp)
L43:
  cmpl   $0x0,-0x18(%rbp)
  jle    L25
  jmp    L14
L10:
  mov    -0x28(%rbp),%edx
  mov    -0x14(%rbp),%eax
  add    %eax,%edx
  mov    -0x24(%rbp),%eax
  mov    %edx,%esi
  mov    %eax,%edi
  call   <setPixel@plt>
  mov    -0x28(%rbp),%eax
  sub    -0x14(%rbp),%eax
  mov    %eax,%edx
  mov    -0x24(%rbp),%eax
  mov    %edx,%esi
  mov    %eax,%edi
  call   <setPixel@plt>
L14:
  mov    -0x14(%rbp),%eax
  lea    0x1(%rax),%edx
  mov    %edx,-0x14(%rbp)
  cmp    %eax,-0x30(%rbp)
  jg     L10
  nop
  nop
  leave
  ret
```

assistant: ```c
void plotEllipse(int xm, int ym, int a, int b) {
  int x = -a, y = 0;
  long e2 = (long)b * b, err = (long)x * (2 * e2 + x) + e2;
  do {
    setPixel(xm - x, ym + y);
    setPixel(xm + x, ym + y);
    setPixel(xm + x, ym - y);
    setPixel(xm - x, ym - y);
    e2 = 2 * err;
    if (e2 >= (x * 2 + 1) * (long)b * b)
      err += (++x * 2 + 1) * (long)b * b;
    if (e2 <= (y * 2 + 1) * (long)a * a)
      err += (++y * 2 + 1) * (long)a * a;
  } while (x <= 0);
  while (y++ < b) {
    setPixel(xm, ym + y);
    setPixel(xm, ym - y);
  }
}
```