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

```asm
<c4matrix>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %rbx
  sub    $0x48,%rsp
  mov    %edi,-0x34(%rbp)
  mov    %esi,-0x38(%rbp)
  mov    %edx,-0x3c(%rbp)
  mov    %ecx,-0x40(%rbp)
  mov    %r8d,-0x44(%rbp)
  mov    %r9d,-0x48(%rbp)
  mov    -0x38(%rbp),%eax
  sub    -0x34(%rbp),%eax
  add    $0x1,%eax
  mov    %eax,%eax
  shl    $0x3,%rax
  mov    %rax,%rdi
  call   <malloc@plt>
  mov    %rax,-0x18(%rbp)
  cmpq   $0x0,-0x18(%rbp)
  jne    L56
  mov    $0x14,%edi
  call   <exit@plt>
L56:
  mov    -0x34(%rbp),%eax
  cltq
  shl    $0x3,%rax
  neg    %rax
  add    %rax,-0x18(%rbp)
  mov    -0x34(%rbp),%eax
  mov    %eax,-0x1c(%rbp)
  jmp    L99
L77:
  mov    -0x40(%rbp),%eax
  sub    -0x3c(%rbp),%eax
  add    $0x1,%eax
  mov    %eax,%eax
  shl    $0x3,%rax
  mov    -0x1c(%rbp),%edx
  movslq %edx,%rdx
  lea    0x0(,%rdx,8),%rcx
  mov    -0x18(%rbp),%rdx
  lea    (%rcx,%rdx,1),%rbx
  mov    %rax,%rdi
  call   <malloc@plt>
  mov    %rax,(%rbx)
  mov    -0x1c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rax
  test   %rax,%rax
  jne    L26
  mov    $0x14,%edi
  call   <exit@plt>
L26:
  mov    -0x1c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x3c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  neg    %rax
  mov    %rax,%rcx
  mov    -0x1c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rsi
  mov    -0x18(%rbp),%rax
  add    %rsi,%rax
  add    %rcx,%rdx
  mov    %rdx,(%rax)
  mov    -0x3c(%rbp),%eax
  mov    %eax,-0x24(%rbp)
  jmp    L61
L44:
  mov    -0x48(%rbp),%eax
  sub    -0x44(%rbp),%eax
  add    $0x1,%eax
  mov    %eax,%eax
  shl    $0x3,%rax
  mov    -0x1c(%rbp),%edx
  movslq %edx,%rdx
  lea    0x0(,%rdx,8),%rcx
  mov    -0x18(%rbp),%rdx
  add    %rcx,%rdx
  mov    (%rdx),%rcx
  mov    -0x24(%rbp),%edx
  movslq %edx,%rdx
  shl    $0x3,%rdx
  lea    (%rcx,%rdx,1),%rbx
  mov    %rax,%rdi
  call   <malloc@plt>
  mov    %rax,(%rbx)
  mov    -0x1c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x24(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  mov    (%rax),%rax
  test   %rax,%rax
  jne    L55
  mov    $0x14,%edi
  call   <exit@plt>
L55:
  mov    -0x1c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x24(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x44(%rbp),%eax
  cltq
  shl    $0x3,%rax
  neg    %rax
  mov    %rax,%rsi
  mov    -0x1c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rcx
  mov    -0x18(%rbp),%rax
  add    %rcx,%rax
  mov    (%rax),%rcx
  mov    -0x24(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rcx,%rax
  add    %rsi,%rdx
  mov    %rdx,(%rax)
  mov    -0x44(%rbp),%eax
  mov    %eax,-0x20(%rbp)
  jmp    L35
L47:
  mov    0x18(%rbp),%eax
  sub    0x10(%rbp),%eax
  add    $0x1,%eax
  mov    %eax,%edx
  mov    -0x1c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rcx
  mov    -0x18(%rbp),%rax
  add    %rcx,%rax
  mov    (%rax),%rcx
  mov    -0x24(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rcx,%rax
  mov    (%rax),%rcx
  mov    -0x20(%rbp),%eax
  cltq
  shl    $0x3,%rax
  lea    (%rcx,%rax,1),%rbx
  mov    %rdx,%rdi
  call   <malloc@plt>
  mov    %rax,(%rbx)
  mov    -0x1c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x24(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x20(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  mov    (%rax),%rax
  test   %rax,%rax
  jne    L74
  mov    $0x14,%edi
  call   <exit@plt>
L74:
  mov    -0x1c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x24(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x20(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    0x10(%rbp),%eax
  cltq
  neg    %rax
  mov    %rax,%rsi
  mov    -0x1c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rcx
  mov    -0x18(%rbp),%rax
  add    %rcx,%rax
  mov    (%rax),%rcx
  mov    -0x24(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rcx,%rax
  mov    (%rax),%rcx
  mov    -0x20(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rcx,%rax
  add    %rsi,%rdx
  mov    %rdx,(%rax)
  addl   $0x1,-0x20(%rbp)
L35:
  mov    -0x20(%rbp),%eax
  cmp    -0x48(%rbp),%eax
  jle    L47
  addl   $0x1,-0x24(%rbp)
L61:
  mov    -0x24(%rbp),%eax
  cmp    -0x40(%rbp),%eax
  jle    L44
  addl   $0x1,-0x1c(%rbp)
L99:
  mov    -0x1c(%rbp),%eax
  cmp    -0x38(%rbp),%eax
  jle    L77
  mov    -0x18(%rbp),%rax
  mov    -0x8(%rbp),%rbx
  leave
  ret
```

assistant: ```c
unsigned char ****c4matrix(nql, nqh, nzl, nzh, nrl, nrh, ncl, nch)
int nrl, nrh, ncl, nch, nzl, nzh, nql, nqh;
{
  unsigned char ****m;
  int i, j, k;
  m = (unsigned char ****)malloc((unsigned)(nqh - nql + 1) * sizeof(unsigned char ***));
  if (!m)
    exit(20);
  m -= nql;
  for (k = nql; k <= nqh; k++) {
    m[k] = (unsigned char ***)malloc((unsigned)(nzh - nzl + 1) * sizeof(unsigned char **));
    if (!m[k])
      exit(20);
    m[k] -= nzl;
    for (i = nzl; i <= nzh; i++) {
      m[k][i] = (unsigned char **)malloc((unsigned)(nrh - nrl + 1) * sizeof(unsigned char *));
      if (!m[k][i])
        exit(20);
      m[k][i] -= nrl;
      for (j = nrl; j <= nrh; j++) {
        m[k][i][j] = (unsigned char *)malloc((unsigned)(nch - ncl + 1) * sizeof(unsigned char));
        if (!m[k][i][j])
          exit(20);
        m[k][i][j] -= ncl;
      }
    }
  }
  return m;
}
```