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

```asm
<implicit_precalc_3Dz>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x70,%rsp
  mov    %rdi,-0x48(%rbp)
  mov    %rsi,-0x50(%rbp)
  mov    %rdx,-0x58(%rbp)
  mov    %rcx,-0x60(%rbp)
  movsd  %xmm0,-0x68(%rbp)
  mov    %r8d,-0x6c(%rbp)
  mov    %r9d,-0x70(%rbp)
  mov    0x10(%rbp),%eax
  cltq
  shl    $0x3,%eax
  mov    %eax,%edi
  call   <malloc@plt>
  mov    %rax,-0x28(%rbp)
  mov    0x10(%rbp),%eax
  cltq
  shl    $0x3,%eax
  mov    %eax,%edi
  call   <malloc@plt>
  mov    %rax,-0x20(%rbp)
  mov    0x10(%rbp),%eax
  cltq
  shl    $0x3,%eax
  mov    %eax,%edi
  call   <malloc@plt>
  mov    %rax,-0x18(%rbp)
  mov    0x10(%rbp),%eax
  cltq
  shl    $0x3,%eax
  mov    %eax,%edi
  call   <malloc@plt>
  mov    %rax,-0x10(%rbp)
  mov    0x10(%rbp),%eax
  cltq
  shl    $0x3,%eax
  mov    %eax,%edi
  call   <malloc@plt>
  mov    %rax,-0x8(%rbp)
  mov    0x10(%rbp),%edi
  call   <tridiag_malloc@plt>
  mov    0x18(%rbp),%eax
  mov    %eax,-0x38(%rbp)
  jmp    L30
L42:
  movl   $0x0,-0x34(%rbp)
  jmp    L56
L29:
  movl   $0x0,-0x30(%rbp)
  jmp    L54
L9:
  mov    -0x38(%rbp),%eax
  imul   -0x70(%rbp),%eax
  imul   0x10(%rbp),%eax
  mov    %eax,%edx
  mov    -0x34(%rbp),%eax
  imul   0x10(%rbp),%eax
  add    %eax,%edx
  mov    -0x30(%rbp),%eax
  add    %edx,%eax
  mov    %eax,-0x2c(%rbp)
  mov    -0x2c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x50(%rbp),%rax
  add    %rax,%rdx
  mov    -0x30(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rcx
  mov    -0x28(%rbp),%rax
  add    %rcx,%rax
  movsd  (%rdx),%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x2c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x58(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  movsd  D3(%rip),%xmm0
  divsd  -0x68(%rbp),%xmm0
  mov    -0x30(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x2c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x60(%rbp),%rax
  add    %rax,%rdx
  mov    -0x30(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rcx
  mov    -0x18(%rbp),%rax
  add    %rcx,%rax
  movsd  (%rdx),%xmm0
  movsd  %xmm0,(%rax)
  movsd  D3(%rip),%xmm0
  movapd %xmm0,%xmm1
  divsd  -0x68(%rbp),%xmm1
  mov    -0x2c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    -0x30(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  mulsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x30(%rbp)
L54:
  mov    -0x30(%rbp),%eax
  cmp    0x10(%rbp),%eax
  jl     L9
  mov    -0x38(%rbp),%eax
  imul   -0x70(%rbp),%eax
  imul   0x10(%rbp),%eax
  mov    %eax,%edx
  mov    -0x34(%rbp),%eax
  imul   0x10(%rbp),%eax
  add    %edx,%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x48(%rbp),%rax
  lea    (%rdx,%rax,1),%rdi
  mov    -0x10(%rbp),%rcx
  mov    -0x18(%rbp),%rdx
  mov    -0x20(%rbp),%rsi
  mov    -0x28(%rbp),%rax
  mov    0x10(%rbp),%r9d
  mov    %rdi,%r8
  mov    %rax,%rdi
  call   <tridiag_premalloc@plt>
  addl   $0x1,-0x34(%rbp)
L56:
  mov    -0x34(%rbp),%eax
  cmp    -0x70(%rbp),%eax
  jl     L29
  addl   $0x1,-0x38(%rbp)
L30:
  mov    -0x38(%rbp),%eax
  cmp    0x20(%rbp),%eax
  jl     L42
  mov    $0x0,%eax
  call   <tridiag_free@plt>
  mov    -0x28(%rbp),%rax
  mov    %rax,%rdi
  call   <free@plt>
  mov    -0x20(%rbp),%rax
  mov    %rax,%rdi
  call   <free@plt>
  mov    -0x18(%rbp),%rax
  mov    %rax,%rdi
  call   <free@plt>
  mov    -0x10(%rbp),%rax
  mov    %rax,%rdi
  call   <free@plt>
  mov    -0x8(%rbp),%rax
  mov    %rax,%rdi
  call   <free@plt>
  nop
  leave
  ret
```

tool_calls: name: retrieve_data
arguments: tag: D3
type_infered: byte[8]

tool: {"D3": [0x00,0x00,0x00,0x00,0x00,0x00,0xf0,0x3f]}

assistant: ```c
void implicit_precalc_3Dz(double *phi, double *az, double *bz, double *cz, double dt, int L, int M, int N, int Lstart, int Lend) {
  int ii, jj, kk;
  int index;
  double *a = malloc(N * sizeof(*a));
  double *b = malloc(N * sizeof(*b));
  double *c = malloc(N * sizeof(*c));
  double *r = malloc(N * sizeof(*r));
  double *new_row = malloc(N * sizeof(*new_row));
  tridiag_malloc(N);
  for (ii = Lstart; ii < Lend; ii++) {
    for (jj = 0; jj < M; jj++) {
      for (kk = 0; kk < N; kk++) {
        index = ii * M * N + jj * N + kk;
        a[kk] = az[index];
        b[kk] = bz[index] + 1 / dt;
        c[kk] = cz[index];
        r[kk] = 1 / dt * phi[index];
      }
      tridiag_premalloc(a, b, c, r, &phi[ii * M * N + jj * N], N);
    }
  }
  tridiag_free();
  free(a);
  free(b);
  free(c);
  free(r);
  free(new_row);
}
```