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

```asm
<sigproc_demux_fifodata>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  mov    %r8,-0x18(%rsp)
  mov    %r9,-0x20(%rsp)
  test   %rdx,%rdx
  je     L10
  mov    %rsi,%r13
  mov    0x40(%rsp),%rsi
  mov    %rdi,%r11
  mov    %rdx,%r10
  mov    %rcx,%rbx
  lea    (%r9,%r9,1),%rax
  lea    (%rsi,%rsi,1),%r15
  mov    %r15,%r8
  imul   %rcx,%r8
  cmp    $0x1,%rcx
  jne    L1
  lea    -0x1(%r13),%r9
  lea    -0x1(%rdi,%r13,1),%rbx
  xor    %r14d,%r14d
  sub    %rax,%r9
  sub    %rax,%rbx
  lea    0x0(,%rdx,4),%r12
  lea    (%rdi,%rax,1),%r15
  nopl   0x0(%rax)
L7:
  cmpq   $0x0,-0x20(%rsp)
  je     L3
  mov    -0x18(%rsp),%rax
  lea    (%r15,%r9,1),%rdx
  lea    (%rax,%r14,4),%rcx
  nopl   (%rax)
L11:
  movzbl -0x1(%rdx),%eax
  movzbl (%rdx),%esi
  pxor   %xmm2,%xmm2
  sub    $0x2,%rdx
  shl    $0x8,%eax
  or     %esi,%eax
  xor    $0x80,%ah
  sub    $0x8000,%eax
  cvtsi2sd %eax,%xmm2
  mulsd  %xmm1,%xmm2
  addsd  %xmm0,%xmm2
  cvtsd2ss %xmm2,%xmm2
  movss  %xmm2,(%rcx)
  add    %r12,%rcx
  cmp    %rdx,%rbx
  jne    L11
L3:
  test   %r8,%r8
  je     L97
  mov    0x38(%rsp),%rax
  xor    %esi,%esi
  lea    (%rax,%r14,1),%rbp
L19:
  mov    %rsi,%rax
  xor    %edx,%edx
  mov    %rsi,%rdi
  mov    %r9,%rcx
  div    %r8
  shr    $0x3,%rdi
  sub    %rdi,%rcx
  movzbl (%r11,%rcx,1),%edi
  mov    %rsi,%rcx
  add    $0x1,%rsi
  and    $0x7,%ecx
  sar    %cl,%edi
  and    $0x1,%edi
  imul   %r10,%rdx
  add    %rbp,%rax
  mov    %dil,(%rax,%rdx,1)
  cmp    %rsi,%r8
  jne    L19
L97:
  add    $0x1,%r14
  add    %r13,%r9
  add    %r13,%rbx
  cmp    %r14,%r10
  jne    L7
L10:
  pop    %rbx
  xor    %eax,%eax
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L1:
  lea    -0x1(%rdi,%r13,1),%rbp
  lea    -0x1(%r13),%r9
  mov    %r13,-0x8(%rsp)
  xor    %edi,%edi
  sub    %rax,%r9
  sub    %rax,%rbp
  add    %r11,%rax
  mov    0x38(%rsp),%r13
  mov    %rax,-0x10(%rsp)
  lea    0x0(,%rdx,4),%r12
  nopl   0x0(%rax)
L99:
  mov    -0x10(%rsp),%rax
  cmpq   $0x0,-0x20(%rsp)
  lea    (%rax,%r9,1),%rdx
  mov    -0x18(%rsp),%rax
  lea    (%rax,%rdi,4),%rcx
  je     L55
  nopw   0x0(%rax,%rax,1)
L65:
  movzbl -0x1(%rdx),%eax
  movzbl (%rdx),%esi
  pxor   %xmm2,%xmm2
  sub    $0x2,%rdx
  shl    $0x8,%eax
  or     %esi,%eax
  xor    $0x80,%ah
  sub    $0x8000,%eax
  cvtsi2sd %eax,%xmm2
  mulsd  %xmm1,%xmm2
  addsd  %xmm0,%xmm2
  cvtsd2ss %xmm2,%xmm2
  movss  %xmm2,(%rcx)
  add    %r12,%rcx
  cmp    %rbp,%rdx
  jne    L65
L55:
  xor    %esi,%esi
  test   %r8,%r8
  je     L15
  nopw   0x0(%rax,%rax,1)
L5:
  mov    %rsi,%rax
  xor    %edx,%edx
  mov    %rsi,%r14
  mov    %r9,%rcx
  div    %r15
  shr    $0x3,%r14
  sub    %r14,%rcx
  movzbl (%r11,%rcx,1),%r14d
  mov    %rsi,%rcx
  add    $0x1,%rsi
  and    $0x7,%ecx
  sar    %cl,%r14d
  and    $0x1,%r14d
  imul   %r10,%rdx
  add    %r13,%rax
  add    %rdi,%rdx
  imul   %rbx,%rdx
  mov    %r14b,(%rax,%rdx,1)
  cmp    %r8,%rsi
  jne    L5
L15:
  mov    -0x8(%rsp),%rax
  add    $0x1,%rdi
  add    %rax,%r9
  add    %rax,%rbp
  cmp    %rdi,%r10
  jne    L99
  pop    %rbx
  xor    %eax,%eax
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

assistant: ```c
int sigproc_demux_fifodata(const char *fData, size_t bytesPerSample, size_t nSamples, size_t adcSdmCycRatio, float *adcData, size_t nAdcCh, char *sdmData, size_t nSdmCh, double adcVoffset, double adcLSB) {
  int v;
  ssize_t i, j, idx0, b0, bi, bs, ch, ss;
  for (i = 0; i < nSamples; i++) {
    for (j = 0; j < nAdcCh; j++) {
      idx0 = bytesPerSample - 1 - j * 2;
      v = ((unsigned char)(fData[i * bytesPerSample + idx0 - 1]) << 8 | (unsigned char)(fData[i * bytesPerSample + idx0]));
      v = (v ^ 0x8000) - 0x8000;
      adcData[j * nSamples + i] = v * adcLSB + adcVoffset;
    }
    b0 = nAdcCh * 2;
    for (j = 0; j < adcSdmCycRatio * nSdmCh * 2; j++) {
      bi = bytesPerSample - 1 - b0 - (ssize_t)(j / 8);
      bs = j % 8;
      ss = (ssize_t)(j / (nSdmCh * 2));
      ch = j % (nSdmCh * 2);
      sdmData[ch * nSamples * adcSdmCycRatio + i * adcSdmCycRatio + ss] = ((unsigned char)(fData[i * bytesPerSample + bi]) >> bs) & 0x1;
    }
  }
  return 0;
}
```