user: Converte this assembly snippet into its equivalent C code:

```asm
<update_cell_2D_quickest_a_lliffe>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  add    $0xffffffffffffff80,%rsp
  mov    %rdi,-0x48(%rbp)
  mov    %rsi,-0x50(%rbp)
  mov    %rdx,-0x58(%rbp)
  mov    %ecx,-0x5c(%rbp)
  mov    %r8d,-0x60(%rbp)
  mov    %r9d,-0x64(%rbp)
  movsd  %xmm0,-0x70(%rbp)
  movsd  %xmm1,-0x78(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x8(%rbp)
  xor    %eax,%eax
  pxor   %xmm0,%xmm0
  movsd  %xmm0,-0x20(%rbp)
  pxor   %xmm0,%xmm0
  movsd  %xmm0,-0x18(%rbp)
  pxor   %xmm0,%xmm0
  movsd  %xmm0,-0x10(%rbp)
  mov    -0x60(%rbp),%eax
  imul   -0x64(%rbp),%eax
  mov    %eax,%edx
  mov    -0x5c(%rbp),%eax
  add    %edx,%eax
  mov    %eax,-0x3c(%rbp)
  mov    -0x64(%rbp),%edx
  mov    -0x60(%rbp),%esi
  mov    -0x5c(%rbp),%eax
  push   -0x58(%rbp)
  lea    -0x38(%rbp),%rcx
  push   %rcx
  mov    -0x3c(%rbp),%ecx
  push   %rcx
  push   $0x0
  mov    $0x0,%r9d
  mov    $0x1,%r8d
  mov    0x10(%rbp),%ecx
  mov    %eax,%edi
  call   <get_uface_2d@plt>
  add    $0x20,%rsp
  movsd  -0x38(%rbp),%xmm0
  movsd  -0x10(%rbp),%xmm1
  mov    -0x70(%rbp),%rcx
  mov    -0x64(%rbp),%edx
  mov    -0x60(%rbp),%esi
  mov    -0x5c(%rbp),%eax
  push   -0x48(%rbp)
  lea    -0x30(%rbp),%rdi
  push   %rdi
  mov    -0x3c(%rbp),%edi
  push   %rdi
  push   $0x1
  movapd %xmm1,%xmm2
  movapd %xmm0,%xmm1
  movq   %rcx,%xmm0
  mov    $0x0,%r9d
  mov    $0x1,%r8d
  mov    0x10(%rbp),%ecx
  mov    %eax,%edi
  call   <get_face_2d_quickest_a_lliffe@plt>
  add    $0x20,%rsp
  mov    -0x64(%rbp),%edx
  mov    -0x60(%rbp),%esi
  mov    -0x5c(%rbp),%eax
  sub    $0x8,%rsp
  push   -0x48(%rbp)
  lea    -0x28(%rbp),%rcx
  push   %rcx
  mov    -0x3c(%rbp),%ecx
  push   %rcx
  mov    $0x0,%r9d
  mov    $0x1,%r8d
  mov    0x10(%rbp),%ecx
  mov    %eax,%edi
  call   <get_face_grad_2d_lliffe@plt>
  add    $0x20,%rsp
  movsd  -0x30(%rbp),%xmm1
  movsd  -0x38(%rbp),%xmm0
  mulsd  %xmm1,%xmm0
  movsd  -0x20(%rbp),%xmm1
  addsd  %xmm1,%xmm0
  movsd  %xmm0,-0x20(%rbp)
  movsd  -0x28(%rbp),%xmm0
  movsd  -0x18(%rbp),%xmm1
  addsd  %xmm1,%xmm0
  movsd  %xmm0,-0x18(%rbp)
  mov    -0x64(%rbp),%edx
  mov    -0x60(%rbp),%esi
  mov    -0x5c(%rbp),%eax
  push   -0x58(%rbp)
  lea    -0x38(%rbp),%rcx
  push   %rcx
  mov    -0x3c(%rbp),%ecx
  push   %rcx
  push   $0x0
  mov    $0x0,%r9d
  mov    $0xffffffff,%r8d
  mov    0x10(%rbp),%ecx
  mov    %eax,%edi
  call   <get_uface_2d@plt>
  add    $0x20,%rsp
  movsd  -0x38(%rbp),%xmm0
  movsd  -0x10(%rbp),%xmm1
  mov    -0x70(%rbp),%rcx
  mov    -0x64(%rbp),%edx
  mov    -0x60(%rbp),%esi
  mov    -0x5c(%rbp),%eax
  push   -0x48(%rbp)
  lea    -0x30(%rbp),%rdi
  push   %rdi
  mov    -0x3c(%rbp),%edi
  push   %rdi
  push   $0xffffffffffffffff
  movapd %xmm1,%xmm2
  movapd %xmm0,%xmm1
  movq   %rcx,%xmm0
  mov    $0x0,%r9d
  mov    $0xffffffff,%r8d
  mov    0x10(%rbp),%ecx
  mov    %eax,%edi
  call   <get_face_2d_quickest_a_lliffe@plt>
  add    $0x20,%rsp
  mov    -0x64(%rbp),%edx
  mov    -0x60(%rbp),%esi
  mov    -0x5c(%rbp),%eax
  sub    $0x8,%rsp
  push   -0x48(%rbp)
  lea    -0x28(%rbp),%rcx
  push   %rcx
  mov    -0x3c(%rbp),%ecx
  push   %rcx
  mov    $0x0,%r9d
  mov    $0xffffffff,%r8d
  mov    0x10(%rbp),%ecx
  mov    %eax,%edi
  call   <get_face_grad_2d_lliffe@plt>
  add    $0x20,%rsp
  movsd  -0x30(%rbp),%xmm1
  movsd  -0x38(%rbp),%xmm0
  mulsd  %xmm0,%xmm1
  movsd  -0x20(%rbp),%xmm0
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x20(%rbp)
  movsd  -0x28(%rbp),%xmm0
  movsd  -0x18(%rbp),%xmm1
  addsd  %xmm1,%xmm0
  movsd  %xmm0,-0x18(%rbp)
  mov    -0x64(%rbp),%edx
  mov    -0x60(%rbp),%esi
  mov    -0x5c(%rbp),%eax
  push   -0x58(%rbp)
  lea    -0x38(%rbp),%rcx
  push   %rcx
  mov    -0x3c(%rbp),%ecx
  push   %rcx
  push   $0x1
  mov    $0x1,%r9d
  mov    $0x0,%r8d
  mov    0x10(%rbp),%ecx
  mov    %eax,%edi
  call   <get_uface_2d@plt>
  add    $0x20,%rsp
  movsd  -0x38(%rbp),%xmm0
  movsd  -0x10(%rbp),%xmm1
  mov    -0x70(%rbp),%rcx
  mov    -0x64(%rbp),%edx
  mov    -0x60(%rbp),%esi
  mov    -0x5c(%rbp),%eax
  push   -0x48(%rbp)
  lea    -0x30(%rbp),%rdi
  push   %rdi
  mov    -0x3c(%rbp),%edi
  push   %rdi
  push   $0x1
  movapd %xmm1,%xmm2
  movapd %xmm0,%xmm1
  movq   %rcx,%xmm0
  mov    $0x1,%r9d
  mov    $0x0,%r8d
  mov    0x10(%rbp),%ecx
  mov    %eax,%edi
  call   <get_face_2d_quickest_a_lliffe@plt>
  add    $0x20,%rsp
  mov    -0x64(%rbp),%edx
  mov    -0x60(%rbp),%esi
  mov    -0x5c(%rbp),%eax
  sub    $0x8,%rsp
  push   -0x48(%rbp)
  lea    -0x28(%rbp),%rcx
  push   %rcx
  mov    -0x3c(%rbp),%ecx
  push   %rcx
  mov    $0x1,%r9d
  mov    $0x0,%r8d
  mov    0x10(%rbp),%ecx
  mov    %eax,%edi
  call   <get_face_grad_2d_lliffe@plt>
  add    $0x20,%rsp
  movsd  -0x30(%rbp),%xmm1
  movsd  -0x38(%rbp),%xmm0
  mulsd  %xmm1,%xmm0
  movsd  -0x20(%rbp),%xmm1
  addsd  %xmm1,%xmm0
  movsd  %xmm0,-0x20(%rbp)
  movsd  -0x28(%rbp),%xmm0
  movsd  -0x18(%rbp),%xmm1
  addsd  %xmm1,%xmm0
  movsd  %xmm0,-0x18(%rbp)
  mov    -0x64(%rbp),%edx
  mov    -0x60(%rbp),%esi
  mov    -0x5c(%rbp),%eax
  push   -0x58(%rbp)
  lea    -0x38(%rbp),%rcx
  push   %rcx
  mov    -0x3c(%rbp),%ecx
  push   %rcx
  push   $0x1
  mov    $0xffffffff,%r9d
  mov    $0x0,%r8d
  mov    0x10(%rbp),%ecx
  mov    %eax,%edi
  call   <get_uface_2d@plt>
  add    $0x20,%rsp
  movsd  -0x38(%rbp),%xmm0
  movsd  -0x10(%rbp),%xmm1
  mov    -0x70(%rbp),%rcx
  mov    -0x64(%rbp),%edx
  mov    -0x60(%rbp),%esi
  mov    -0x5c(%rbp),%eax
  push   -0x48(%rbp)
  lea    -0x30(%rbp),%rdi
  push   %rdi
  mov    -0x3c(%rbp),%edi
  push   %rdi
  push   $0xffffffffffffffff
  movapd %xmm1,%xmm2
  movapd %xmm0,%xmm1
  movq   %rcx,%xmm0
  mov    $0xffffffff,%r9d
  mov    $0x0,%r8d
  mov    0x10(%rbp),%ecx
  mov    %eax,%edi
  call   <get_face_2d_quickest_a_lliffe@plt>
  add    $0x20,%rsp
  mov    -0x64(%rbp),%edx
  mov    -0x60(%rbp),%esi
  mov    -0x5c(%rbp),%eax
  sub    $0x8,%rsp
  push   -0x48(%rbp)
  lea    -0x28(%rbp),%rcx
  push   %rcx
  mov    -0x3c(%rbp),%ecx
  push   %rcx
  mov    $0xffffffff,%r9d
  mov    $0x0,%r8d
  mov    0x10(%rbp),%ecx
  mov    %eax,%edi
  call   <get_face_grad_2d_lliffe@plt>
  add    $0x20,%rsp
  movsd  -0x30(%rbp),%xmm1
  movsd  -0x38(%rbp),%xmm0
  mulsd  %xmm0,%xmm1
  movsd  -0x20(%rbp),%xmm0
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x20(%rbp)
  movsd  -0x28(%rbp),%xmm0
  movsd  -0x18(%rbp),%xmm1
  addsd  %xmm1,%xmm0
  movsd  %xmm0,-0x18(%rbp)
  mov    -0x60(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x5c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  movsd  -0x78(%rbp),%xmm0
  mulsd  -0x18(%rbp),%xmm0
  subsd  -0x20(%rbp),%xmm0
  mulsd  -0x70(%rbp),%xmm0
  mov    -0x60(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x50(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x5c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  nop
  mov    -0x8(%rbp),%rax
  sub    %fs:0x28,%rax
  je     L0
  call   <__stack_chk_fail@plt>
L0:
  leave
  ret
```

assistant: ```c
void update_cell_2D_quickest_a_lliffe(double **sc_old, double **sc_new, double *u_buff, int iX, int iY, int nX, int nY, double delta_t, double alpha) {
  int tid;
  double sum_face_a = 0.;
  double sum_face_d = 0.;
  double u_face;
  double u_face_t = 0.;
  double sc_face;
  double sc_face_grad;
  tid = iY * nX + iX;
  get_uface_2d(iX, iY, nX, nY, 1, 0, 0, tid, &u_face, u_buff);
  get_face_2d_quickest_a_lliffe(iX, iY, nX, nY, 1, 0, 1, tid, delta_t, u_face, u_face_t, &sc_face, sc_old);
  get_face_grad_2d_lliffe(iX, iY, nX, nY, 1, 0, tid, &sc_face_grad, sc_old);
  sum_face_a += sc_face * u_face;
  sum_face_d += sc_face_grad;
  get_uface_2d(iX, iY, nX, nY, -1, 0, 0, tid, &u_face, u_buff);
  get_face_2d_quickest_a_lliffe(iX, iY, nX, nY, -1, 0, -1, tid, delta_t, u_face, u_face_t, &sc_face, sc_old);
  get_face_grad_2d_lliffe(iX, iY, nX, nY, -1, 0, tid, &sc_face_grad, sc_old);
  sum_face_a -= sc_face * u_face;
  sum_face_d += sc_face_grad;
  get_uface_2d(iX, iY, nX, nY, 0, 1, 1, tid, &u_face, u_buff);
  get_face_2d_quickest_a_lliffe(iX, iY, nX, nY, 0, 1, 1, tid, delta_t, u_face, u_face_t, &sc_face, sc_old);
  get_face_grad_2d_lliffe(iX, iY, nX, nY, 0, 1, tid, &sc_face_grad, sc_old);
  sum_face_a += sc_face * u_face;
  sum_face_d += sc_face_grad;
  get_uface_2d(iX, iY, nX, nY, 0, -1, 1, tid, &u_face, u_buff);
  get_face_2d_quickest_a_lliffe(iX, iY, nX, nY, 0, -1, -1, tid, delta_t, u_face, u_face_t, &sc_face, sc_old);
  get_face_grad_2d_lliffe(iX, iY, nX, nY, 0, -1, tid, &sc_face_grad, sc_old);
  sum_face_a -= sc_face * u_face;
  sum_face_d += sc_face_grad;
  sc_new[iY][iX] = sc_old[iY][iX] + 1. * delta_t * (1. * alpha * sum_face_d - sum_face_a);
}
```