user: What is the c source code of the assembly code below:

```asm
<calculate_uv>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  movsd  %xmm0,-0x18(%rbp)
  movsd  %xmm1,-0x20(%rbp)
  movsd  %xmm2,-0x28(%rbp)
  mov    %edi,-0x2c(%rbp)
  mov    %esi,-0x30(%rbp)
  mov    %rdx,-0x38(%rbp)
  mov    %rcx,-0x40(%rbp)
  mov    %r8,-0x48(%rbp)
  mov    %r9,-0x50(%rbp)
  movl   $0x1,-0x8(%rbp)
  jmp    L55
L56:
  movl   $0x1,-0x4(%rbp)
  jmp    L57
L6:
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  movsd  -0x18(%rbp),%xmm1
  movapd %xmm1,%xmm2
  divsd  -0x20(%rbp),%xmm2
  mov    -0x8(%rbp),%eax
  cltq
  add    $0x1,%rax
  lea    0x0(,%rax,8),%rdx
  mov    0x10(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x10(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm3
  subsd  %xmm3,%xmm1
  mulsd  %xmm2,%xmm1
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  subsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x50(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  movsd  -0x18(%rbp),%xmm1
  movapd %xmm1,%xmm2
  divsd  -0x28(%rbp),%xmm2
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x10(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  add    $0x1,%rax
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x10(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm3
  subsd  %xmm3,%xmm1
  mulsd  %xmm2,%xmm1
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  subsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x4(%rbp)
L57:
  mov    -0x4(%rbp),%eax
  cmp    -0x30(%rbp),%eax
  jl     L6
  mov    -0x30(%rbp),%eax
  mov    %eax,-0x4(%rbp)
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  movsd  -0x18(%rbp),%xmm1
  movapd %xmm1,%xmm2
  divsd  -0x20(%rbp),%xmm2
  mov    -0x8(%rbp),%eax
  cltq
  add    $0x1,%rax
  lea    0x0(,%rax,8),%rdx
  mov    0x10(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x10(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm3
  subsd  %xmm3,%xmm1
  mulsd  %xmm2,%xmm1
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  subsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x8(%rbp)
L55:
  mov    -0x8(%rbp),%eax
  cmp    -0x2c(%rbp),%eax
  jl     L56
  mov    -0x2c(%rbp),%eax
  mov    %eax,-0x8(%rbp)
  movl   $0x1,-0x4(%rbp)
  jmp    L18
L3:
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x50(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  movsd  -0x18(%rbp),%xmm1
  movapd %xmm1,%xmm2
  divsd  -0x28(%rbp),%xmm2
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x10(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  add    $0x1,%rax
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x10(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm3
  subsd  %xmm3,%xmm1
  mulsd  %xmm2,%xmm1
  mov    -0x8(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x4(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  subsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x4(%rbp)
L18:
  mov    -0x4(%rbp),%eax
  cmp    -0x30(%rbp),%eax
  jl     L3
  nop
  nop
  pop    %rbp
  ret
```

assistant: ```c
void calculate_uv(double dt, double dx, double dy, int imax, int jmax, double **U, double **V, double **F, double **G, double **P) {
  int i;
  int j;
  for (i = 1; i < imax; i++) {
    for (j = 1; j < jmax; j++) {
      U[i][j] = F[i][j] - dt / dx * (P[i + 1][j] - P[i][j]);
      V[i][j] = G[i][j] - dt / dy * (P[i][j + 1] - P[i][j]);
    }
    j = jmax;
    U[i][j] = F[i][j] - dt / dx * (P[i + 1][j] - P[i][j]);
  }
  i = imax;
  for (j = 1; j < jmax; j++) {
    V[i][j] = G[i][j] - dt / dy * (P[i][j + 1] - P[i][j]);
  }
}
```