user: 请将以下的汇编代码转换成C语言代码：

```asm
<test_preexisting>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x480,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,-0x8(%rbp)
  xor    %eax,%eax
  movabs $0x6972772074736554,%rax
  movabs $0x6d6f7320676e6974,%rdx
  mov    %rax,-0x450(%rbp)
  mov    %rdx,-0x448(%rbp)
  movabs $0x66667574732065,%rcx
  mov    %rcx,-0x440(%rbp)
  movabs $0x4141414141414141,%rax
  mov    %rax,-0x45a(%rbp)
  movw   $0x41,-0x452(%rbp)
  movabs $0x6972772041414141,%rax
  movabs $0x6d6f7320676e6974,%rdx
  mov    %rax,-0x430(%rbp)
  mov    %rdx,-0x428(%rbp)
  mov    %rcx,-0x420(%rbp)
  lea    -0x410(%rbp),%rax
  lea    D21(%rip),%rdx
  mov    $0x200,%esi
  mov    %rax,%rdi
  call   <fmemopen@plt>
  mov    %rax,-0x478(%rbp)
  cmpq   $0x0,-0x478(%rbp)
  setne  %al
  movzbl %al,%eax
  mov    %eax,%edi
  call   <assert@plt>
  mov    -0x478(%rbp),%rdx
  lea    -0x450(%rbp),%rax
  mov    %rdx,%rcx
  mov    $0x18,%edx
  mov    $0x1,%esi
  mov    %rax,%rdi
  call   <fwrite@plt>
  mov    %rax,-0x470(%rbp)
  cmpq   $0x18,-0x470(%rbp)
  sete   %al
  movzbl %al,%eax
  mov    %eax,%edi
  call   <assert@plt>
  mov    -0x478(%rbp),%rax
  mov    %rax,%rdi
  call   <fclose@plt>
  mov    %eax,-0x47c(%rbp)
  cmpl   $0x0,-0x47c(%rbp)
  sete   %al
  movzbl %al,%eax
  mov    %eax,%edi
  call   <assert@plt>
  lea    -0x410(%rbp),%rax
  lea    D28(%rip),%rdx
  mov    $0x200,%esi
  mov    %rax,%rdi
  call   <fmemopen@plt>
  mov    %rax,-0x478(%rbp)
  cmpq   $0x0,-0x478(%rbp)
  setne  %al
  movzbl %al,%eax
  mov    %eax,%edi
  call   <assert@plt>
  lea    -0x210(%rbp),%rax
  mov    $0x200,%esi
  mov    %rax,%rdi
  call   <bzero@plt>
  mov    -0x478(%rbp),%rdx
  lea    -0x210(%rbp),%rax
  mov    %rdx,%rcx
  mov    $0x200,%edx
  mov    $0x1,%esi
  mov    %rax,%rdi
  call   <fread@plt>
  mov    %rax,-0x468(%rbp)
  cmpq   $0x200,-0x468(%rbp)
  sete   %al
  movzbl %al,%eax
  mov    %eax,%edi
  call   <assert@plt>
  lea    -0x210(%rbp),%rdx
  lea    -0x450(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <strcmp@plt>
  test   %rax,%rax
  sete   %al
  movzbl %al,%eax
  mov    %eax,%edi
  call   <assert@plt>
  mov    -0x478(%rbp),%rax
  mov    %rax,%rdi
  call   <fclose@plt>
  mov    %eax,-0x47c(%rbp)
  cmpl   $0x0,-0x47c(%rbp)
  sete   %al
  movzbl %al,%eax
  mov    %eax,%edi
  call   <assert@plt>
  lea    -0x450(%rbp),%rax
  lea    D21(%rip),%rdx
  mov    $0x4,%esi
  mov    %rax,%rdi
  call   <fmemopen@plt>
  mov    %rax,-0x478(%rbp)
  cmpq   $0x0,-0x478(%rbp)
  setne  %al
  movzbl %al,%eax
  mov    %eax,%edi
  call   <assert@plt>
  mov    -0x478(%rbp),%rdx
  lea    -0x45a(%rbp),%rax
  mov    %rdx,%rcx
  mov    $0xa,%edx
  mov    $0x1,%esi
  mov    %rax,%rdi
  call   <fwrite@plt>
  mov    %rax,-0x470(%rbp)
  cmpq   $0x4,-0x470(%rbp)
  sete   %al
  movzbl %al,%eax
  mov    %eax,%edi
  call   <assert@plt>
  mov    -0x478(%rbp),%rax
  mov    %rax,%rdi
  call   <fclose@plt>
  mov    %eax,-0x47c(%rbp)
  lea    -0x430(%rbp),%rdx
  lea    -0x450(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <strcmp@plt>
  test   %rax,%rax
  sete   %al
  movzbl %al,%eax
  mov    %eax,%edi
  call   <assert@plt>
  nop
  mov    -0x8(%rbp),%rax
  sub    %fs:0x28,%rax
  je     L6
  call   <__stack_chk_fail@plt>
L6:
  leave
  ret
```

tool_calls: name: read_data
arguments: label: D21
type_guessed: string
name: read_data
arguments: label: D28
type_guessed: string

tool: D21: w

tool: D28: r

assistant: ```c
void test_preexisting() {
  char buf[512];
  char buf2[512];
  char str[] = "Test writing some stuff";
  char str2[] = "AAAAAAAAA";
  char str3[] = "AAAA writing some stuff";
  FILE *fp;
  size_t nofw, nofr;
  int rc;
  fp = fmemopen(buf, sizeof(buf), "w");
  assert(fp != NULL);
  nofw = fwrite(str, 1, sizeof(str), fp);
  assert(nofw == sizeof(str));
  rc = fclose(fp);
  assert(rc == 0);
  fp = fmemopen(buf, sizeof(buf), "r");
  assert(fp != NULL);
  bzero(buf2, sizeof(buf2));
  nofr = fread(buf2, 1, sizeof(buf2), fp);
  assert(nofr == sizeof(buf2));
  assert(strcmp(str, buf2) == 0);
  rc = fclose(fp);
  assert(rc == 0);
  fp = fmemopen(str, 4, "w");
  assert(fp != NULL);
  nofw = fwrite(str2, 1, sizeof(str2), fp);
  assert(nofw == 4);
  rc = fclose(fp);
  assert(strcmp(str, str3) == 0);
}
```