user: Demonstrate the C code that generates the assembly output below:

```asm
<u2f>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x570,%rsp
  mov    %rdi,-0x548(%rbp)
  mov    %rsi,-0x550(%rbp)
  mov    %edx,-0x554(%rbp)
  mov    %rcx,-0x560(%rbp)
  mov    %r8,-0x568(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x8(%rbp)
  xor    %eax,%eax
  cmpq   $0x0,-0x568(%rbp)
  jne    L68
  mov    -0x554(%rbp),%eax
  cltq
  mov    %eax,%edx
  mov    %edx,%eax
  shl    $0x3,%eax
  add    %edx,%eax
  shl    $0x3,%eax
  mov    %eax,%edi
  call   <malloc@plt>
  mov    %rax,-0x530(%rbp)
  jmp    L50
L68:
  mov    -0x568(%rbp),%rax
  mov    %rax,-0x530(%rbp)
L50:
  cmpl   $0x8,-0x554(%rbp)
  jle    L69
  lea    -0x500(%rbp),%rdi
  lea    -0x520(%rbp),%rcx
  mov    -0x554(%rbp),%edx
  mov    -0x550(%rbp),%rsi
  mov    -0x548(%rbp),%rax
  mov    %rdi,%r8
  mov    %rax,%rdi
  call   <normu@plt>
  lea    -0x500(%rbp),%r8
  lea    -0x520(%rbp),%rdi
  mov    -0x554(%rbp),%ecx
  mov    -0x550(%rbp),%rdx
  mov    -0x530(%rbp),%rsi
  mov    -0x548(%rbp),%rax
  mov    %r8,%r9
  mov    %rdi,%r8
  mov    %rax,%rdi
  call   <lin_fmN@plt>
  mov    -0x554(%rbp),%edx
  mov    -0x530(%rbp),%rsi
  lea    -0x290(%rbp),%rax
  mov    $0x9,%ecx
  mov    %rax,%rdi
  call   <cov_mat@plt>
  lea    -0x4e0(%rbp),%rcx
  lea    -0x290(%rbp),%rax
  mov    $0x9,%edx
  mov    %rcx,%rsi
  mov    %rax,%rdi
  call   <lap_eig@plt>
  lea    -0x290(%rbp),%rax
  mov    $0x9,%esi
  mov    %rax,%rdi
  call   <trnm@plt>
  jmp    L85
L69:
  mov    -0x554(%rbp),%ecx
  mov    -0x550(%rbp),%rdx
  mov    -0x530(%rbp),%rsi
  mov    -0x548(%rbp),%rax
  mov    %rax,%rdi
  call   <lin_fm@plt>
  lea    -0x490(%rbp),%rcx
  lea    -0x290(%rbp),%rdx
  mov    -0x530(%rbp),%rsi
  lea    -0x4e0(%rbp),%rax
  mov    $0x8,%r9d
  mov    %rcx,%r8
  mov    $0x9,%ecx
  mov    %rax,%rdi
  call   <svduv@plt>
L85:
  cmpl   $0x8,-0x554(%rbp)
  jle    L26
  movl   $0x0,-0x534(%rbp)
  movl   $0x1,-0x538(%rbp)
  jmp    L135
L18:
  mov    -0x538(%rbp),%eax
  cltq
  movsd  -0x4e0(%rbp,%rax,8),%xmm1
  mov    -0x534(%rbp),%eax
  cltq
  movsd  -0x4e0(%rbp,%rax,8),%xmm0
  comisd %xmm1,%xmm0
  jbe    L137
  mov    -0x538(%rbp),%eax
  mov    %eax,-0x534(%rbp)
L137:
  addl   $0x1,-0x538(%rbp)
L135:
  cmpl   $0x8,-0x538(%rbp)
  jle    L18
  mov    -0x534(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  lea    -0x290(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x528(%rbp)
  jmp    L98
L26:
  lea    -0x290(%rbp),%rax
  add    $0x40,%rax
  mov    %rax,-0x528(%rbp)
L98:
  movl   $0x0,-0x538(%rbp)
  jmp    L28
L128:
  mov    -0x538(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x560(%rbp),%rax
  add    %rax,%rdx
  mov    -0x528(%rbp),%rax
  movsd  (%rax),%xmm0
  movsd  %xmm0,(%rdx)
  addq   $0x48,-0x528(%rbp)
  addl   $0x1,-0x538(%rbp)
L28:
  cmpl   $0x8,-0x538(%rbp)
  jle    L128
  mov    -0x560(%rbp),%rax
  mov    %rax,%rdi
  call   <singulF@plt>
  cmpl   $0x8,-0x554(%rbp)
  jle    L59
  lea    -0x500(%rbp),%rdx
  lea    -0x520(%rbp),%rcx
  mov    -0x560(%rbp),%rax
  mov    %rcx,%rsi
  mov    %rax,%rdi
  call   <denormF@plt>
L59:
  cmpq   $0x0,-0x568(%rbp)
  jne    L74
  mov    -0x530(%rbp),%rax
  mov    %rax,%rdi
  call   <free@plt>
L74:
  nop
  mov    -0x8(%rbp),%rax
  sub    %fs:0x28,%rax
  je     L22
  call   <__stack_chk_fail@plt>
L22:
  leave
  ret
```

assistant: ```c
void u2f(const double *u, const int *inl, int len, double *F, double *buffer) {
  double A1[3], A2[3];
  double *Z, V[9 * 9], U[8 * 8], D[9], *p;
  int i, j;
  if (buffer == NULL)
    Z = (double *)malloc(sizeof(double) * 9 * len);
  else
    Z = buffer;
  if (len > 8) {
    normu(u, inl, len, A1, A2);
    lin_fmN(u, Z, inl, len, A1, A2);
    cov_mat(V, Z, len, 9);
    lap_eig(V, D, 9);
    trnm(V, 9);
  } else {
    lin_fm(u, Z, inl, len);
    svduv(D, Z, V, 9, U, 8);
  }
  if (len > 8) {
    j = 0;
    for (i = 1; i < 9; i++)
      if (D[i] < D[j])
        j = i;
    p = V + j;
  } else
    p = V + 8;
  for (i = 0; i < 9; i++) {
    F[i] = *p;
    p += 9;
  }
  singulF(F);
  if (len > 8)
    denormF(F, A1, A2);
  if (buffer == NULL)
    free(Z);
}
```