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

```asm
<letterCombinations>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x70,%rsp
  mov    %rdi,-0x68(%rbp)
  mov    %rsi,-0x70(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x8(%rbp)
  xor    %eax,%eax
  movl   $0x20,-0x40(%rbp)
  movb   $0x0,-0x3c(%rbp)
  movl   $0x0,-0x3b(%rbp)
  movb   $0x0,-0x37(%rbp)
  movl   $0x636261,-0x36(%rbp)
  movb   $0x0,-0x32(%rbp)
  movl   $0x666564,-0x31(%rbp)
  movb   $0x0,-0x2d(%rbp)
  movl   $0x696867,-0x2c(%rbp)
  movb   $0x0,-0x28(%rbp)
  movl   $0x6c6b6a,-0x27(%rbp)
  movb   $0x0,-0x23(%rbp)
  movl   $0x6f6e6d,-0x22(%rbp)
  movb   $0x0,-0x1e(%rbp)
  movl   $0x73727170,-0x1d(%rbp)
  movb   $0x0,-0x19(%rbp)
  movl   $0x767574,-0x18(%rbp)
  movb   $0x0,-0x14(%rbp)
  movl   $0x7a797877,-0x13(%rbp)
  movb   $0x0,-0xf(%rbp)
  movl   $0x1,-0x58(%rbp)
  movl   $0x0,-0x54(%rbp)
  movl   $0x0,-0x5c(%rbp)
  jmp    L9
L30:
  mov    -0x54(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x68(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x30,%al
  je     L9
  mov    -0x54(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x68(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x31,%al
  jne    L48
  jmp    L9
L48:
  mov    -0x54(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x68(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x37,%al
  je     L76
  mov    -0x54(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x68(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  cmp    $0x39,%al
  jne    L12
L76:
  shll   $0x2,-0x58(%rbp)
  jmp    L77
L12:
  mov    -0x58(%rbp),%edx
  mov    %edx,%eax
  add    %eax,%eax
  add    %edx,%eax
  mov    %eax,-0x58(%rbp)
L77:
  addl   $0x1,-0x54(%rbp)
L9:
  mov    -0x54(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x68(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  test   %al,%al
  jne    L30
  mov    -0x58(%rbp),%eax
  cltq
  shl    $0x3,%rax
  mov    %rax,%rdi
  call   <malloc@plt>
  mov    %rax,-0x50(%rbp)
  cmpl   $0x0,-0x54(%rbp)
  jne    L51
  mov    -0x70(%rbp),%rax
  movl   $0x0,(%rax)
  mov    -0x50(%rbp),%rax
  jmp    L33
L51:
  mov    -0x54(%rbp),%eax
  cltq
  mov    %rax,%rdi
  call   <malloc@plt>
  mov    %rax,-0x48(%rbp)
  lea    -0x5c(%rbp),%rdi
  lea    -0x40(%rbp),%rcx
  mov    -0x48(%rbp),%rdx
  mov    -0x68(%rbp),%rsi
  mov    -0x50(%rbp),%rax
  mov    %rdi,%r9
  mov    %rcx,%r8
  mov    $0x0,%ecx
  mov    %rax,%rdi
  mov    $0x0,%eax
  call   <getLetterCom@plt>
  mov    -0x5c(%rbp),%edx
  mov    -0x70(%rbp),%rax
  mov    %edx,(%rax)
  mov    -0x50(%rbp),%rax
L33:
  mov    -0x8(%rbp),%rdx
  sub    %fs:0x28,%rdx
  je     L91
  call   <__stack_chk_fail@plt>
L91:
  leave
  ret
```

assistant: ```c
char **letterCombinations(char *digits, int *returnSize) {
  char map[10][5] = {" ", "", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"};
  char **res, *tmp;
  int num = 1, length = 0, top = 0;
  while (digits[length]) {
    if (digits[length] == '0' || digits[length] == '1')
      continue;
    else if (digits[length] == '7' || digits[length] == '9')
      num *= 4;
    else
      num *= 3;
    length++;
  }
  res = (char **)malloc(sizeof(char *) * num);
  if (length == 0) {
    *returnSize = 0;
    return res;
  }
  tmp = (char *)malloc(sizeof(char) * length);
  getLetterCom(res, digits, tmp, 0, map, &top);
  *returnSize = top;
  return res;
}
```