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

```asm
<updateSolutionEconomic_CFP64>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x58,%rsp
  mov    %rdi,0x20(%rsp)
  mov    %rsi,%r12
  mov    %rdx,0x48(%rsp)
  mov    %ecx,%r15d
  mov    %r8,0x38(%rsp)
  movslq %ecx,%rax
  mov    %rax,0x18(%rsp)
  shl    $0x4,%rax
  mov    %rax,0x40(%rsp)
  lea    -0x10(%rdx,%rax,1),%rax
  movsd  (%rax),%xmm4
  movsd  %xmm4,0x10(%rsp)
  movsd  0x8(%rax),%xmm7
  movsd  %xmm7,0x8(%rsp)
  lea    -0x1(%rcx),%r13d
  test   %r13d,%r13d
  jle    L96
  lea    0x4(%rdi),%rbx
  lea    0x8(%rdx),%rbp
  lea    -0x2(%rcx),%eax
  lea    0xc(%rdi,%rax,8),%r14
L66:
  pxor   %xmm5,%xmm5
  cvtss2sd -0x4(%rbx),%xmm5
  pxor   %xmm1,%xmm1
  cvtss2sd (%rbx),%xmm1
  movsd  -0x8(%rbp),%xmm2
  movsd  0x0(%rbp),%xmm3
  movapd %xmm5,%xmm4
  mulsd  %xmm2,%xmm4
  movapd %xmm1,%xmm0
  mulsd  %xmm3,%xmm0
  subsd  %xmm0,%xmm4
  movapd %xmm5,%xmm0
  mulsd  %xmm3,%xmm0
  movapd %xmm1,%xmm6
  mulsd  %xmm2,%xmm6
  addsd  %xmm6,%xmm0
  ucomisd %xmm0,%xmm4
  jp     L104
L79:
  movsd  0x10(%rsp),%xmm2
  subsd  %xmm4,%xmm2
  movsd  %xmm2,0x10(%rsp)
  movsd  0x8(%rsp),%xmm5
  subsd  %xmm0,%xmm5
  movsd  %xmm5,0x8(%rsp)
  add    $0x8,%rbx
  add    $0x10,%rbp
  cmp    %r14,%rbx
  jne    L66
L96:
  mov    0x18(%rsp),%rax
  lea    0x0(,%rax,8),%rbx
  mov    0x20(%rsp),%rax
  lea    -0x8(%rax,%rbx,1),%rax
  pxor   %xmm0,%xmm0
  cvtss2sd (%rax),%xmm0
  pxor   %xmm1,%xmm1
  cvtss2sd 0x4(%rax),%xmm1
  movsd  0x10(%rsp),%xmm4
  movapd %xmm4,%xmm3
  mulsd  %xmm0,%xmm3
  movsd  0x8(%rsp),%xmm7
  movapd %xmm7,%xmm2
  mulsd  %xmm1,%xmm2
  movapd %xmm3,%xmm5
  subsd  %xmm2,%xmm5
  movsd  %xmm5,0x28(%rsp)
  mulsd  %xmm0,%xmm7
  mulsd  %xmm1,%xmm4
  movapd %xmm4,%xmm2
  movapd %xmm7,%xmm4
  addsd  %xmm2,%xmm4
  movsd  %xmm4,0x30(%rsp)
  ucomisd %xmm4,%xmm5
  jp     L117
L116:
  lea    (%r15,%r15,1),%edx
  mov    0x38(%rsp),%r14
  mov    -0x8(%r14,%rbx,1),%rax
  shl    $0x4,%rax
  lea    -0x10(%r12,%rax,1),%rax
  movsd  0x30(%rsp),%xmm0
  addsd  0x8(%rax),%xmm0
  movsd  0x28(%rsp),%xmm1
  addsd  (%rax),%xmm1
  movsd  %xmm1,(%rax)
  movsd  %xmm0,0x8(%rax)
  test   %r13d,%r13d
  jle    L50
  movslq %edx,%rax
  mov    0x40(%rsp),%rbx
  mov    0x20(%rsp),%rsi
  add    %rsi,%rbx
  mov    0x48(%rsp),%r13
  add    $0x8,%r13
  lea    -0x2(%r15),%edx
  add    %rax,%rdx
  lea    0x8(%rsi,%rdx,8),%rbp
  mov    0x18(%rsp),%r15
  sub    %rax,%r15
L91:
  pxor   %xmm6,%xmm6
  cvtss2sd (%rbx,%r15,8),%xmm6
  movsd  %xmm6,0x8(%rsp)
  pxor   %xmm7,%xmm7
  cvtss2sd 0x4(%rbx,%r15,8),%xmm7
  movsd  %xmm7,0x10(%rsp)
  movsd  -0x8(%r13),%xmm5
  movsd  %xmm5,0x18(%rsp)
  movsd  0x0(%r13),%xmm6
  movsd  %xmm6,0x20(%rsp)
  pxor   %xmm4,%xmm4
  cvtss2sd -0x8(%rbx),%xmm4
  pxor   %xmm1,%xmm1
  cvtss2sd -0x4(%rbx),%xmm1
  movsd  0x28(%rsp),%xmm7
  movapd %xmm7,%xmm3
  mulsd  %xmm4,%xmm3
  movsd  0x30(%rsp),%xmm6
  movapd %xmm6,%xmm0
  mulsd  %xmm1,%xmm0
  subsd  %xmm0,%xmm3
  mulsd  %xmm4,%xmm6
  movapd %xmm6,%xmm0
  mulsd  %xmm1,%xmm7
  addsd  %xmm7,%xmm0
  ucomisd %xmm0,%xmm3
  jp     L57
L92:
  movsd  0x18(%rsp),%xmm2
  subsd  %xmm3,%xmm2
  movsd  0x20(%rsp),%xmm3
  subsd  %xmm0,%xmm3
  movsd  0x8(%rsp),%xmm5
  movapd %xmm5,%xmm0
  mulsd  %xmm2,%xmm0
  movsd  0x10(%rsp),%xmm7
  movapd %xmm7,%xmm1
  mulsd  %xmm3,%xmm1
  subsd  %xmm1,%xmm0
  mulsd  %xmm3,%xmm5
  movapd %xmm5,%xmm1
  mulsd  %xmm2,%xmm7
  addsd  %xmm7,%xmm1
  ucomisd %xmm1,%xmm0
  jp     L3
L60:
  mov    (%r14),%rax
  shl    $0x4,%rax
  lea    -0x10(%r12,%rax,1),%rax
  addsd  0x8(%rax),%xmm1
  addsd  (%rax),%xmm0
  movsd  %xmm0,(%rax)
  movsd  %xmm1,0x8(%rax)
  add    $0x8,%rbx
  add    $0x8,%r14
  add    $0x10,%r13
  cmp    %rbp,%rbx
  jne    L91
L50:
  add    $0x58,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L104:
  movapd %xmm5,%xmm0
  call   <__muldc3>
  movapd %xmm0,%xmm4
  movapd %xmm1,%xmm0
  jmp    L79
L117:
  movsd  0x8(%rsp),%xmm3
  movsd  0x10(%rsp),%xmm2
  call   <__muldc3>
  movsd  %xmm0,0x28(%rsp)
  movsd  %xmm1,0x30(%rsp)
  jmp    L116
L57:
  movsd  0x30(%rsp),%xmm3
  movsd  0x28(%rsp),%xmm2
  movapd %xmm4,%xmm0
  call   <__muldc3>
  movapd %xmm0,%xmm3
  movapd %xmm1,%xmm0
  jmp    L92
L3:
  movsd  0x10(%rsp),%xmm1
  movsd  0x8(%rsp),%xmm0
  call   <__muldc3>
  jmp    L60
```

assistant: ```c
void updateSolutionEconomic_CFP64(float _Complex *mat, double _Complex *x, double _Complex *r, int n, long long *Idxs) {
  int i, j, offset1, offset2;
  double _Complex t = r[n - 1];
  for (i = 0; i < n - 1; ++i) {
    t -= mat[i] * r[i];
  }
  t *= mat[n - 1];
  offset1 = n;
  offset2 = 2 * n - 1;
  x[Idxs[n - 1] - 1] += t;
  for (i = 0; i < n - 1; ++i) {
    x[Idxs[i] - 1] += mat[i + offset1] * (r[i] - mat[i + offset2] * t);
  }
}
```