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

```asm
<rfftf1>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x28,%rsp
  mov    0x4(%r8),%eax
  mov    %edi,0x10(%rsp)
  mov    %eax,0x14(%rsp)
  test   %eax,%eax
  jle    L80
  mov    %edi,%eax
  movslq 0x14(%rsp),%rdi
  mov    %rsi,%r13
  mov    %rdx,%r14
  cltd
  mov    %rcx,%r9
  mov    $0x1,%r10d
  mov    %r13,(%rsp)
  add    $0x1,%rdi
  mov    %r14,0x8(%rsp)
  mov    %r14,%r11
  xor    %ebx,%ebx
  mov    (%r8,%rdi,4),%esi
  mov    %r10d,%r14d
  mov    $0x1,%r15d
  mov    %r9,%r10
  idiv   %esi
  mov    %r13,%rdx
  mov    %eax,%ecx
  mov    0x10(%rsp),%eax
  mov    %ecx,%r12d
  sub    %esi,%eax
  mov    %eax,%ebp
  lea    -0x4(%r8,%rdi,4),%rax
  mov    $0x1,%edi
  mov    %rax,%r13
  jmp    L91
  nopl   0x0(%rax,%rax,1)
L239:
  cmp    $0x3,%esi
  jne    L192
  lea    (%rdi,%rbp,1),%ecx
  mov    %r12d,%esi
  mov    %r10,0x18(%rsp)
  movslq %ecx,%rcx
  lea    (%r10,%rcx,8),%r9
  mov    %r11,%rcx
  call   <radf3@plt>
  mov    0x18(%rsp),%r10
L159:
  add    $0x1,%r14d
  cmp    %r14d,0x14(%rsp)
  jl     L60
L231:
  mov    0x0(%r13),%esi
  mov    %r12d,%eax
  mov    %ebx,%r15d
  cltd
  xor    $0x1,%r15d
  idiv   %esi
  mov    %eax,%r8d
  mov    0x10(%rsp),%eax
  mov    %r8d,%ecx
  cltd
  idiv   %r12d
  mov    (%rsp),%rdx
  imul   %eax,%ecx
  mov    %eax,%edi
  lea    -0x1(%rsi),%eax
  imul   %edi,%eax
  sub    %eax,%ebp
  mov    0x8(%rsp),%rax
  test   %ebx,%ebx
  mov    %rax,%r11
  cmove  %rdx,%r11
  cmove  %rax,%rdx
L111:
  mov    %r8d,%r12d
  mov    %ebx,%r8d
  sub    $0x4,%r13
  mov    %r15d,%ebx
  mov    %r8d,%r15d
L91:
  movslq %ebp,%r8
  lea    (%r10,%r8,8),%r8
  cmp    $0x4,%esi
  je     L103
  jg     L199
  cmp    $0x2,%esi
  jne    L239
  mov    %r11,%rcx
  mov    %r12d,%esi
  mov    %r10,0x18(%rsp)
  add    $0x1,%r14d
  call   <radf2@plt>
  mov    0x18(%rsp),%r10
  cmp    %r14d,0x14(%rsp)
  jge    L231
L60:
  mov    (%rsp),%r13
  mov    0x8(%rsp),%r14
  cmp    $0x1,%ebx
  je     L80
L53:
  mov    0x10(%rsp),%ebx
  test   %ebx,%ebx
  jle    L80
  lea    0x8(%r14),%rax
  cmp    %rax,%r13
  je     L140
  lea    -0x1(%rbx),%eax
  cmp    $0x2,%eax
  jbe    L140
  shr    %ebx
  xor    %eax,%eax
  mov    %ebx,%edx
  shl    $0x4,%rdx
  nopl   (%rax)
L194:
  movupd (%r14,%rax,1),%xmm1
  movups %xmm1,0x0(%r13,%rax,1)
  add    $0x10,%rax
  cmp    %rdx,%rax
  jne    L194
  mov    0x10(%rsp),%ebx
  mov    %ebx,%eax
  and    $0xfffffffe,%eax
  and    $0x1,%ebx
  je     L80
  movsd  (%r14,%rax,8),%xmm0
  movsd  %xmm0,0x0(%r13,%rax,8)
L80:
  add    $0x28,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nop
L199:
  cmp    $0x5,%esi
  jne    L192
  lea    (%rdi,%rbp,1),%ecx
  lea    (%rcx,%rdi,1),%esi
  movslq %ecx,%rcx
  lea    (%rsi,%rdi,1),%r9d
  movslq %esi,%rsi
  movslq %r9d,%r9
  lea    (%r10,%rsi,8),%rsi
  lea    (%r10,%r9,8),%r9
  push   %r9
  lea    (%r10,%rcx,8),%r9
  mov    %r11,%rcx
  push   %rsi
  mov    %r12d,%esi
  mov    %r10,0x28(%rsp)
  call   <radf5@plt>
  pop    %rdi
  pop    %r8
  mov    0x18(%rsp),%r10
  jmp    L159
  nopl   0x0(%rax)
L103:
  lea    (%rdi,%rbp,1),%ecx
  sub    $0x8,%rsp
  movslq %ecx,%rsi
  add    %edi,%ecx
  movslq %ecx,%rcx
  lea    (%r10,%rsi,8),%r9
  mov    %r12d,%esi
  lea    (%r10,%rcx,8),%rcx
  push   %rcx
  mov    %r11,%rcx
  mov    %r10,0x28(%rsp)
  call   <radf4@plt>
  pop    %r9
  pop    %r10
  mov    0x18(%rsp),%r10
  jmp    L159
  xchg   %ax,%ax
L192:
  cmp    $0x1,%edi
  mov    %r10,0x18(%rsp)
  cmovne %ebx,%r15d
  test   %r15d,%r15d
  jne    L16
  sub    $0x8,%rsp
  mov    %r12d,%edx
  add    $0x1,%r14d
  push   %r8
  mov    0x18(%rsp),%r9
  mov    0x10(%rsp),%r8
  call   <radfg@plt>
  pop    %rcx
  pop    %rsi
  cmp    0x14(%rsp),%r14d
  mov    0x18(%rsp),%r10
  jg     L80
  mov    0x0(%r13),%esi
  mov    %r12d,%eax
  mov    0x8(%rsp),%r11
  mov    $0x1,%ebx
  cltd
  idiv   %esi
  mov    %eax,%r8d
  mov    0x10(%rsp),%eax
  mov    %r8d,%ecx
  cltd
  idiv   %r12d
  mov    (%rsp),%rdx
  mov    %eax,%edi
  imul   %eax,%ecx
  lea    -0x1(%rsi),%eax
  imul   %edi,%eax
  sub    %eax,%ebp
  jmp    L111
  nopw   0x0(%rax,%rax,1)
L16:
  sub    $0x8,%rsp
  mov    %r12d,%edx
  add    $0x1,%r14d
  push   %r8
  mov    0x10(%rsp),%r9
  mov    0x18(%rsp),%r8
  call   <radfg@plt>
  pop    %rax
  pop    %rdx
  cmp    0x14(%rsp),%r14d
  mov    0x18(%rsp),%r10
  jg     L153
  mov    0x0(%r13),%esi
  mov    %r12d,%eax
  mov    (%rsp),%r11
  xor    %ebx,%ebx
  cltd
  idiv   %esi
  mov    %eax,%r8d
  mov    0x10(%rsp),%eax
  mov    %r8d,%ecx
  cltd
  idiv   %r12d
  mov    0x8(%rsp),%rdx
  mov    %eax,%edi
  imul   %eax,%ecx
  lea    -0x1(%rsi),%eax
  imul   %edi,%eax
  sub    %eax,%ebp
  jmp    L111
  nop
L140:
  mov    0x10(%rsp),%edx
  xor    %eax,%eax
  cs nopw 0x0(%rax,%rax,1)
L224:
  movsd  (%r14,%rax,8),%xmm0
  movsd  %xmm0,0x0(%r13,%rax,8)
  add    $0x1,%rax
  cmp    %rax,%rdx
  jne    L224
  add    $0x28,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L153:
  mov    (%rsp),%r13
  mov    0x8(%rsp),%r14
  jmp    L53
```

assistant: ```c
void rfftf1(int n, double c[], double ch[], const double wa[], const int ifac[13 + 2]) {
  int i;
  int k1, l1, l2, na, kh, nf, ip, iw, ix2, ix3, ix4, ido, idl1;
  double *cinput, *coutput;
  nf = ifac[1];
  na = 1;
  l2 = n;
  iw = n - 1;
  for (k1 = 1; k1 <= nf; ++k1) {
    kh = nf - k1;
    ip = ifac[kh + 2];
    l1 = l2 / ip;
    ido = n / l2;
    idl1 = ido * l1;
    iw -= (ip - 1) * ido;
    na = !na;
    if (na) {
      cinput = ch;
      coutput = c;
    } else {
      cinput = c;
      coutput = ch;
    }
    switch (ip) {
    case 4:
      ix2 = iw + ido;
      ix3 = ix2 + ido;
      radf4(ido, l1, cinput, coutput, &wa[iw], &wa[ix2], &wa[ix3]);
      break;
    case 2:
      radf2(ido, l1, cinput, coutput, &wa[iw]);
      break;
    case 3:
      ix2 = iw + ido;
      radf3(ido, l1, cinput, coutput, &wa[iw], &wa[ix2]);
      break;
    case 5:
      ix2 = iw + ido;
      ix3 = ix2 + ido;
      ix4 = ix3 + ido;
      radf5(ido, l1, cinput, coutput, &wa[iw], &wa[ix2], &wa[ix3], &wa[ix4]);
      break;
    default:
      if (ido == 1)
        na = !na;
      if (na == 0) {
        radfg(ido, ip, l1, idl1, c, ch, &wa[iw]);
        na = 1;
      } else {
        radfg(ido, ip, l1, idl1, ch, c, &wa[iw]);
        na = 0;
      }
    }
    l2 = l1;
  }
  if (na == 1)
    return;
  for (i = 0; i < n; i++)
    c[i] = ch[i];
}
```