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

```asm
<main>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r13
  push   %r12
  push   %rbx
  sub    $0x48,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,-0x28(%rbp)
  xor    %eax,%eax
  mov    %rsp,%rax
  mov    %rax,%rbx
  movl   $0xd,-0x4c(%rbp)
  mov    -0x4c(%rbp),%eax
  cltq
  sub    $0x1,%rax
  mov    %rax,-0x48(%rbp)
  mov    -0x4c(%rbp),%eax
  cltq
  mov    %rax,%r12
  mov    $0x0,%r13d
  mov    -0x4c(%rbp),%eax
  cltq
  mov    %rax,%r10
  mov    $0x0,%r11d
  mov    -0x4c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    $0x10,%eax
  sub    $0x1,%rax
  add    %rdx,%rax
  mov    $0x10,%ecx
  mov    $0x0,%edx
  div    %rcx
  imul   $0x10,%rax,%rax
  mov    %rax,%rcx
  and    $0xfffffffffffff000,%rcx
  mov    %rsp,%rdx
  sub    %rcx,%rdx
L108:
  cmp    %rdx,%rsp
  je     L139
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L108
L139:
  mov    %rax,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  mov    %rax,%rdx
  and    $0xfff,%edx
  test   %rdx,%rdx
  je     L115
  and    $0xfff,%eax
  sub    $0x8,%rax
  add    %rsp,%rax
  orq    $0x0,(%rax)
L115:
  mov    %rsp,%rax
  add    $0x7,%rax
  shr    $0x3,%rax
  shl    $0x3,%rax
  mov    %rax,-0x40(%rbp)
  mov    -0x4c(%rbp),%eax
  cltq
  sub    $0x1,%rax
  mov    %rax,-0x38(%rbp)
  mov    -0x4c(%rbp),%eax
  cltq
  mov    %rax,%r8
  mov    $0x0,%r9d
  mov    -0x4c(%rbp),%eax
  cltq
  mov    %rax,%rsi
  mov    $0x0,%edi
  mov    -0x4c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    $0x10,%eax
  sub    $0x1,%rax
  add    %rdx,%rax
  mov    $0x10,%edi
  mov    $0x0,%edx
  div    %rdi
  imul   $0x10,%rax,%rax
  mov    %rax,%rcx
  and    $0xfffffffffffff000,%rcx
  mov    %rsp,%rdx
  sub    %rcx,%rdx
L17:
  cmp    %rdx,%rsp
  je     L78
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L17
L78:
  mov    %rax,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  mov    %rax,%rdx
  and    $0xfff,%edx
  test   %rdx,%rdx
  je     L45
  and    $0xfff,%eax
  sub    $0x8,%rax
  add    %rsp,%rax
  orq    $0x0,(%rax)
L45:
  mov    %rsp,%rax
  add    $0x7,%rax
  shr    $0x3,%rax
  shl    $0x3,%rax
  mov    %rax,-0x30(%rbp)
  mov    -0x4c(%rbp),%edx
  mov    -0x40(%rbp),%rax
  mov    %edx,%esi
  mov    %rax,%rdi
  call   <leibniz@plt>
  mov    -0x4c(%rbp),%eax
  mov    %eax,%edx
  shr    $0x1f,%edx
  add    %edx,%eax
  sar    %eax
  mov    %eax,-0x58(%rbp)
  mov    -0x4c(%rbp),%eax
  and    $0x1,%eax
  test   %eax,%eax
  jne    L131
  subl   $0x1,-0x58(%rbp)
L131:
  movl   $0x0,-0x54(%rbp)
  jmp    L0
L91:
  mov    -0x54(%rbp),%eax
  lea    (%rax,%rax,1),%ecx
  mov    -0x4c(%rbp),%eax
  sub    %ecx,%eax
  mov    %eax,%edx
  mov    -0x40(%rbp),%rax
  mov    %edx,%esi
  mov    %rax,%rdi
  call   <printseq@plt>
  mov    -0x54(%rbp),%eax
  lea    (%rax,%rax,1),%ecx
  mov    -0x4c(%rbp),%eax
  sub    %ecx,%eax
  mov    %eax,%edx
  mov    -0x30(%rbp),%rcx
  mov    -0x40(%rbp),%rax
  mov    %rcx,%rsi
  mov    %rax,%rdi
  call   <aitken@plt>
  movl   $0x0,-0x50(%rbp)
  jmp    L89
L130:
  mov    -0x30(%rbp),%rax
  mov    -0x50(%rbp),%edx
  movslq %edx,%rdx
  movsd  (%rax,%rdx,8),%xmm0
  mov    -0x40(%rbp),%rax
  mov    -0x50(%rbp),%edx
  movslq %edx,%rdx
  movsd  %xmm0,(%rax,%rdx,8)
  addl   $0x1,-0x50(%rbp)
L89:
  mov    -0x54(%rbp),%eax
  add    $0x1,%eax
  lea    (%rax,%rax,1),%edx
  mov    -0x4c(%rbp),%eax
  sub    %edx,%eax
  cmp    %eax,-0x50(%rbp)
  jl     L130
  addl   $0x1,-0x54(%rbp)
L0:
  mov    -0x54(%rbp),%eax
  cmp    -0x58(%rbp),%eax
  jl     L91
  mov    -0x4c(%rbp),%eax
  and    $0x1,%eax
  test   %eax,%eax
  jne    L137
  mov    -0x40(%rbp),%rax
  mov    $0x2,%esi
  mov    %rax,%rdi
  call   <printseq@plt>
  jmp    L110
L137:
  mov    -0x40(%rbp),%rax
  mov    $0x1,%esi
  mov    %rax,%rdi
  call   <printseq@plt>
L110:
  mov    %rbx,%rsp
  mov    $0x0,%eax
  mov    -0x28(%rbp),%rdx
  sub    %fs:0x28,%rdx
  je     L116
  call   <__stack_chk_fail@plt>
L116:
  lea    -0x18(%rbp),%rsp
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %rbp
  ret
```

assistant: ```c
int main() {
  const int len = 13;
  double seq1[len];
  double seq2[len];
  int n, i, j;
  leibniz(seq1, len);
  n = len / 2;
  if (len % 2 == 0)
    n--;
  for (i = 0; i < n; i++) {
    printseq(seq1, len - 2 * i);
    aitken(seq1, seq2, len - 2 * i);
    for (j = 0; j < len - 2 * (i + 1); j++)
      seq1[j] = seq2[j];
  }
  if (len % 2 == 0)
    printseq(seq1, 2);
  else
    printseq(seq1, 1);
}
```