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

```asm
<mp_squhf_use_infft>:
  endbr64
  push   %r15
  mov    %r9,%r10
  push   %r14
  mov    %rdx,%r14
  push   %r13
  mov    %esi,%r13d
  mov    %rcx,%rsi
  push   %r12
  push   %rbp
  mov    %edi,%ebp
  push   %rbx
  sub    $0x38,%rsp
  mov    0x70(%rsp),%r15d
  mov    %r8,0x8(%rsp)
  mov    0x78(%rsp),%r9
  mov    0x80(%rsp),%rbx
  mov    %r15d,%ecx
  mov    0x88(%rsp),%r11
  sar    %ecx
  add    $0x1,%ecx
  cmp    %edi,%ecx
  jge    L29
  movslq %ecx,%rdx
  jmp    L6
L8:
  lea    0x1(%rdx),%ecx
  add    $0x1,%rdx
  cmp    %edx,%ebp
  jle    L29
L6:
  mov    0x8(%rsi,%rdx,4),%edi
  mov    %edx,%ecx
  test   %edi,%edi
  je     L8
L29:
  mov    %ebp,%r12d
  mov    %ebp,%edx
  mov    %rsi,%r8
  mov    %ebp,%edi
  shr    $0x1f,%r12d
  sub    %ecx,%edx
  mov    %r13d,%esi
  mov    %r10,0x28(%rsp)
  add    %ebp,%r12d
  mov    %r11,0x18(%rsp)
  sar    %r12d
  mov    %r9,0x10(%rsp)
  add    $0x1,%r12d
  cmp    %edx,%r12d
  cmovl  %edx,%r12d
  mov    %r15d,%edx
  call   <mp_mul_i2d@plt>
  mov    0x18(%rsp),%r11
  mov    %rbx,%rcx
  mov    %r14,%rsi
  mov    0x10(%rsp),%r9
  mov    %r15d,%edi
  mov    %r11,%r8
  mov    %r11,0x20(%rsp)
  mov    %r9,%rdx
  mov    %r9,0x18(%rsp)
  call   <mp_mul_cmul_nt_d1@plt>
  mov    0x28(%rsp),%r10
  mov    %r15d,%edx
  mov    %r13d,%esi
  mov    0x18(%rsp),%rcx
  mov    %r12d,%edi
  mov    %r10,%r8
  mov    %r10,0x10(%rsp)
  call   <mp_mul_d2i@plt>
  mov    0x20(%rsp),%rcx
  mov    %rbx,%rdx
  mov    %r14,%rsi
  mov    %r15d,%edi
  call   <mp_mul_csqu_nt_d1@plt>
  mov    0x8(%rsp),%r8
  mov    %r14,%rcx
  mov    %r15d,%edx
  mov    %r13d,%esi
  mov    %ebp,%edi
  call   <mp_mul_d2i@plt>
  mov    0x10(%rsp),%r10
  mov    (%r10),%eax
  test   %eax,%eax
  jne    L9
  add    $0x38,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax,%rax,1)
L9:
  mov    0x8(%rsp),%rdx
  add    $0x38,%rsp
  mov    %r13d,%esi
  mov    %ebp,%edi
  pop    %rbx
  mov    %r10,%rcx
  pop    %rbp
  mov    %rdx,%r8
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  jmp    10c0 <mp_add@plt>
```

assistant: ```c
void mp_squhf_use_infft(int n, int radix, double infft[], int in[], int out[], int tmp[], int nfft, double tmpfft[], int ip[], double w[]) {
  void mp_add(int n, int radix, int in1[], int in2[], int out[]);
  void mp_mul_i2d(int n, int radix, int nfft, int shift, int in[], double dout[]);
  void mp_mul_cmul_nt_d1(int nfft, double d1[], double d2[], int ip[], double w[]);
  void mp_mul_csqu_nt_d1(int nfft, double d1[], int ip[], double w[]);
  void mp_mul_d2i(int n, int radix, int nfft, double din[], int out[]);
  int n_h, shift;
  shift = (nfft >> 1) + 1;
  while (n > shift) {
    if (in[shift + 2] != 0) {
      break;
    }
    shift++;
  }
  n_h = n / 2 + 1;
  if (n_h < n - shift) {
    n_h = n - shift;
  }
  mp_mul_i2d(n, radix, nfft, shift, in, tmpfft);
  mp_mul_cmul_nt_d1(nfft, infft, tmpfft, ip, w);
  mp_mul_d2i(n_h, radix, nfft, tmpfft, tmp);
  mp_mul_csqu_nt_d1(nfft, infft, ip, w);
  mp_mul_d2i(n, radix, nfft, infft, out);
  if (tmp[0] != 0) {
    mp_add(n, radix, out, tmp, out);
  }
}
```