user: What is the c source code of the assembly code below?

```asm
<ibfR2>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x18,%rsp
  mov    %rdi,-0x88(%rbp)
  mov    %esi,-0x8c(%rbp)
  mov    %edx,-0x90(%rbp)
  mov    -0x90(%rbp),%eax
  add    %eax,%eax
  mov    %eax,-0x7c(%rbp)
  mov    -0x7c(%rbp),%eax
  shl    $0x2,%eax
  mov    %eax,-0x78(%rbp)
  movl   $0x2,-0x74(%rbp)
  mov    -0x74(%rbp),%eax
  add    $0x1,%eax
  mov    %eax,-0x70(%rbp)
  mov    -0x8c(%rbp),%eax
  mov    $0x1,%edx
  mov    %eax,%ecx
  shl    %cl,%edx
  mov    %edx,%eax
  lea    0x3(%rax),%edx
  test   %eax,%eax
  cmovs  %edx,%eax
  sar    $0x2,%eax
  cltd
  idivl  -0x90(%rbp)
  mov    %eax,-0x6c(%rbp)
  mov    -0x88(%rbp),%rax
  mov    %rax,-0x8(%rbp)
  mov    -0x8(%rbp),%rax
  mov    %rax,-0x28(%rbp)
  mov    -0x7c(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x20(%rbp)
  mov    -0x7c(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x18(%rbp)
  mov    -0x7c(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x10(%rbp)
  mov    -0x6c(%rbp),%eax
  mov    %eax,-0x80(%rbp)
  jmp    L7
L16:
  mov    -0x28(%rbp),%rax
  movss  (%rax),%xmm0
  movss  %xmm0,-0x68(%rbp)
  mov    -0x20(%rbp),%rax
  movss  (%rax),%xmm0
  movss  %xmm0,-0x64(%rbp)
  mov    -0x28(%rbp),%rax
  movss  0x4(%rax),%xmm0
  movss  %xmm0,-0x60(%rbp)
  mov    -0x20(%rbp),%rax
  movss  0x4(%rax),%xmm0
  movss  %xmm0,-0x5c(%rbp)
  mov    -0x18(%rbp),%rax
  movss  (%rax),%xmm0
  movss  %xmm0,-0x58(%rbp)
  mov    -0x10(%rbp),%rax
  movss  (%rax),%xmm0
  movss  %xmm0,-0x54(%rbp)
  mov    -0x18(%rbp),%rax
  movss  0x4(%rax),%xmm0
  movss  %xmm0,-0x50(%rbp)
  mov    -0x10(%rbp),%rax
  movss  0x4(%rax),%xmm0
  movss  %xmm0,-0x4c(%rbp)
  movss  -0x68(%rbp),%xmm0
  addss  -0x64(%rbp),%xmm0
  movss  %xmm0,-0x48(%rbp)
  movss  -0x60(%rbp),%xmm0
  addss  -0x5c(%rbp),%xmm0
  movss  %xmm0,-0x44(%rbp)
  movss  -0x68(%rbp),%xmm0
  subss  -0x64(%rbp),%xmm0
  movss  %xmm0,-0x40(%rbp)
  movss  -0x60(%rbp),%xmm0
  subss  -0x5c(%rbp),%xmm0
  movss  %xmm0,-0x3c(%rbp)
  movss  -0x58(%rbp),%xmm0
  addss  -0x54(%rbp),%xmm0
  movss  %xmm0,-0x38(%rbp)
  movss  -0x50(%rbp),%xmm0
  addss  -0x4c(%rbp),%xmm0
  movss  %xmm0,-0x34(%rbp)
  movss  -0x58(%rbp),%xmm0
  subss  -0x54(%rbp),%xmm0
  movss  %xmm0,-0x30(%rbp)
  movss  -0x50(%rbp),%xmm0
  subss  -0x4c(%rbp),%xmm0
  movss  %xmm0,-0x2c(%rbp)
  mov    -0x28(%rbp),%rax
  movss  -0x48(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x28(%rbp),%rax
  add    $0x4,%rax
  movss  -0x44(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x20(%rbp),%rax
  movss  -0x40(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x20(%rbp),%rax
  add    $0x4,%rax
  movss  -0x3c(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x18(%rbp),%rax
  movss  -0x38(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x18(%rbp),%rax
  add    $0x4,%rax
  movss  -0x34(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x10(%rbp),%rax
  movss  -0x30(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x10(%rbp),%rax
  add    $0x4,%rax
  movss  -0x2c(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x74(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movss  (%rax),%xmm0
  movss  %xmm0,-0x68(%rbp)
  mov    -0x70(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movss  (%rax),%xmm0
  movss  %xmm0,-0x5c(%rbp)
  mov    -0x70(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movss  (%rax),%xmm0
  movss  %xmm0,-0x60(%rbp)
  mov    -0x74(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movss  (%rax),%xmm0
  movss  %xmm0,-0x64(%rbp)
  mov    -0x74(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movss  (%rax),%xmm0
  movss  %xmm0,-0x58(%rbp)
  mov    -0x70(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  movss  (%rax),%xmm0
  movss  %xmm0,-0x4c(%rbp)
  mov    -0x70(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movss  (%rax),%xmm0
  movss  %xmm0,-0x50(%rbp)
  mov    -0x74(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  movss  (%rax),%xmm0
  movss  %xmm0,-0x54(%rbp)
  movss  -0x68(%rbp),%xmm0
  subss  -0x5c(%rbp),%xmm0
  movss  %xmm0,-0x48(%rbp)
  movss  -0x60(%rbp),%xmm0
  addss  -0x64(%rbp),%xmm0
  movss  %xmm0,-0x44(%rbp)
  movss  -0x68(%rbp),%xmm0
  addss  -0x5c(%rbp),%xmm0
  movss  %xmm0,-0x40(%rbp)
  movss  -0x60(%rbp),%xmm0
  subss  -0x64(%rbp),%xmm0
  movss  %xmm0,-0x3c(%rbp)
  movss  -0x58(%rbp),%xmm0
  subss  -0x4c(%rbp),%xmm0
  movss  %xmm0,-0x38(%rbp)
  movss  -0x50(%rbp),%xmm0
  addss  -0x54(%rbp),%xmm0
  movss  %xmm0,-0x34(%rbp)
  movss  -0x58(%rbp),%xmm0
  addss  -0x4c(%rbp),%xmm0
  movss  %xmm0,-0x30(%rbp)
  movss  -0x50(%rbp),%xmm0
  subss  -0x54(%rbp),%xmm0
  movss  %xmm0,-0x2c(%rbp)
  mov    -0x74(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movss  -0x48(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x70(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movss  -0x44(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x74(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movss  -0x40(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x70(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movss  -0x3c(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x74(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movss  -0x38(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x70(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movss  -0x34(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x74(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  movss  -0x30(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x70(%rbp),%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  movss  -0x2c(%rbp),%xmm0
  movss  %xmm0,(%rax)
  mov    -0x78(%rbp),%eax
  shl    $0x2,%rax
  add    %rax,-0x28(%rbp)
  mov    -0x78(%rbp),%eax
  shl    $0x2,%rax
  add    %rax,-0x20(%rbp)
  mov    -0x78(%rbp),%eax
  shl    $0x2,%rax
  add    %rax,-0x18(%rbp)
  mov    -0x78(%rbp),%eax
  shl    $0x2,%rax
  add    %rax,-0x10(%rbp)
  subl   $0x1,-0x80(%rbp)
L7:
  cmpl   $0x0,-0x80(%rbp)
  jne    L16
  nop
  nop
  leave
  ret
```

assistant: ```c
void ibfR2(float *ioptr, int M, int NDiffU) {
  unsigned int pos;
  unsigned int posi;
  unsigned int pinc;
  unsigned int pnext;
  unsigned int NSameU;
  unsigned int SameUCnt;
  float *pstrt;
  float *p0r, *p1r, *p2r, *p3r;
  float f0r, f0i, f1r, f1i, f2r, f2i, f3r, f3i;
  float f4r, f4i, f5r, f5i, f6r, f6i, f7r, f7i;
  pinc = NDiffU * 2;
  pnext = pinc * 4;
  pos = 2;
  posi = pos + 1;
  NSameU = ((uint32_t)1 << (M)) / 4 / NDiffU;
  pstrt = ioptr;
  p0r = pstrt;
  p1r = pstrt + pinc;
  p2r = p1r + pinc;
  p3r = p2r + pinc;
  for (SameUCnt = NSameU; SameUCnt > 0; SameUCnt--) {
    f0r = *p0r;
    f1r = *p1r;
    f0i = *(p0r + 1);
    f1i = *(p1r + 1);
    f2r = *p2r;
    f3r = *p3r;
    f2i = *(p2r + 1);
    f3i = *(p3r + 1);
    f4r = f0r + f1r;
    f4i = f0i + f1i;
    f5r = f0r - f1r;
    f5i = f0i - f1i;
    f6r = f2r + f3r;
    f6i = f2i + f3i;
    f7r = f2r - f3r;
    f7i = f2i - f3i;
    *p0r = f4r;
    *(p0r + 1) = f4i;
    *p1r = f5r;
    *(p1r + 1) = f5i;
    *p2r = f6r;
    *(p2r + 1) = f6i;
    *p3r = f7r;
    *(p3r + 1) = f7i;
    f0r = *(p0r + pos);
    f1i = *(p1r + posi);
    f0i = *(p0r + posi);
    f1r = *(p1r + pos);
    f2r = *(p2r + pos);
    f3i = *(p3r + posi);
    f2i = *(p2r + posi);
    f3r = *(p3r + pos);
    f4r = f0r - f1i;
    f4i = f0i + f1r;
    f5r = f0r + f1i;
    f5i = f0i - f1r;
    f6r = f2r - f3i;
    f6i = f2i + f3r;
    f7r = f2r + f3i;
    f7i = f2i - f3r;
    *(p0r + pos) = f4r;
    *(p0r + posi) = f4i;
    *(p1r + pos) = f5r;
    *(p1r + posi) = f5i;
    *(p2r + pos) = f6r;
    *(p2r + posi) = f6i;
    *(p3r + pos) = f7r;
    *(p3r + posi) = f7i;
    p0r += pnext;
    p1r += pnext;
    p2r += pnext;
    p3r += pnext;
  }
}
```