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

```asm
<u2fw>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x548,%rsp
  mov    %rdi,0x18(%rsp)
  mov    %rsi,%r15
  mov    %rdx,%r12
  mov    %ecx,%r13d
  mov    %r8,0x10(%rsp)
  mov    %r9,%r14
  mov    %fs:0x28,%rax
  mov    %rax,0x538(%rsp)
  xor    %eax,%eax
  mov    %r9,0x8(%rsp)
  test   %r9,%r9
  je     L54
L60:
  cmp    $0x8,%r13d
  jle    L48
  lea    0x40(%rsp),%rbp
  lea    0x20(%rsp),%rbx
  mov    %rbp,%r8
  mov    %rbx,%rcx
  mov    %r13d,%edx
  mov    %r15,%rsi
  mov    0x18(%rsp),%rdi
  call   <normu@plt>
  mov    %rbp,%r9
  mov    %rbx,%r8
  mov    %r13d,%ecx
  mov    %r15,%rdx
  mov    0x8(%rsp),%rbp
  mov    %rbp,%rsi
  mov    0x18(%rsp),%rdi
  call   <lin_fmN@plt>
  mov    %r15,%rbx
  lea    -0x1(%r13),%eax
  lea    0x4(%r15,%rax,4),%r15
L90:
  movslq (%rbx),%rax
  movsd  (%r12,%rax,8),%xmm0
  mov    $0x1,%edx
  mov    $0x9,%esi
  mov    %rbp,%rdi
  call   <scalmul@plt>
  add    $0x4,%rbx
  add    $0x48,%rbp
  cmp    %r15,%rbx
  jne    L90
  lea    0x2b0(%rsp),%rbx
  mov    $0x9,%ecx
  mov    %r13d,%edx
  mov    0x8(%rsp),%rsi
  mov    %rbx,%rdi
  call   <cov_mat@plt>
  lea    0x60(%rsp),%rsi
  mov    $0x9,%edx
  mov    %rbx,%rdi
  call   <lap_eig@plt>
  mov    $0x9,%esi
  mov    %rbx,%rdi
  call   <trnm@plt>
  mov    $0x1,%eax
  mov    $0x0,%edx
  lea    0x60(%rsp),%rsi
L0:
  movslq %edx,%rcx
  movsd  0x60(%rsp,%rcx,8),%xmm0
  ucomisd (%rsi,%rax,8),%xmm0
  cmova  %eax,%edx
  add    $0x1,%rax
  cmp    $0x9,%rax
  jne    L0
  movslq %edx,%rdx
  lea    0x2b0(%rsp,%rdx,8),%rax
  jmp    L58
L54:
  lea    (%rcx,%rcx,8),%edi
  shl    $0x3,%edi
  call   <malloc@plt>
  mov    %rax,0x8(%rsp)
  jmp    L60
L48:
  mov    %r13d,%ecx
  mov    %r15,%rdx
  mov    0x8(%rsp),%rbx
  mov    %rbx,%rsi
  mov    0x18(%rsp),%rdi
  call   <lin_fm@plt>
  test   %r13d,%r13d
  jle    L117
  mov    %r15,%rbp
  mov    %r13d,%eax
  lea    (%rbx,%rax,8),%r15
L107:
  movslq 0x0(%rbp),%rax
  movsd  (%r12,%rax,8),%xmm0
  mov    $0x9,%edx
  mov    $0x9,%esi
  mov    %rbx,%rdi
  call   <scalmul@plt>
  add    $0x4,%rbp
  add    $0x8,%rbx
  cmp    %r15,%rbx
  jne    L107
L117:
  lea    0x2b0(%rsp),%rdx
  lea    0x60(%rsp),%rdi
  mov    $0x8,%r9d
  lea    0xb0(%rsp),%r8
  mov    $0x9,%ecx
  mov    0x8(%rsp),%rsi
  call   <svduv@plt>
  lea    0x2f0(%rsp),%rax
L58:
  mov    0x10(%rsp),%rdx
  lea    0x288(%rax),%rcx
L14:
  movsd  (%rax),%xmm0
  movsd  %xmm0,(%rdx)
  add    $0x48,%rax
  add    $0x8,%rdx
  cmp    %rcx,%rax
  jne    L14
  mov    0x10(%rsp),%rdi
  call   <singulF@plt>
  cmp    $0x8,%r13d
  jg     L42
L19:
  test   %r14,%r14
  je     L112
L136:
  mov    0x538(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L59
  add    $0x548,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L42:
  lea    0x40(%rsp),%rdx
  lea    0x20(%rsp),%rsi
  mov    0x10(%rsp),%rdi
  call   <denormF@plt>
  jmp    L19
L112:
  mov    0x8(%rsp),%rdi
  call   <free@plt>
  jmp    L136
L59:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
void u2fw(const double *u, const int *inl, const double *w, 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);
    for (i = 0; i < len; i++) {
      j = inl[i];
      scalmul(Z + 9 * i, w[j], 9, 1);
    }
    cov_mat(V, Z, len, 9);
    lap_eig(V, D, 9);
    trnm(V, 9);
  } else {
    lin_fm(u, Z, inl, len);
    for (i = 0; i < len; i++) {
      j = inl[i];
      scalmul(Z + i, w[j], 9, 9);
    }
    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);
}
```