user: Please show me the C implementation that matches the assembly code listed below:

```asm
<make_window8>:
  endbr64
  push   %r15
  xor    %r8d,%r8d
  xor    %eax,%eax
  push   %r14
  lea    -0x1(%rsi),%r14d
  push   %r13
  mov    %r14d,%r9d
  push   %r12
  mov    %edx,%r12d
  mov    $0x8,%edx
  push   %rbp
  mov    %esi,%ebp
  lea    -0x1(%r12),%r13d
  lea    -0x2(%r12),%r15d
  push   %rbx
  mov    %rdi,%rbx
  sub    $0x3,%r12d
  sub    $0x20,%rsp
  mov    %rcx,0x10(%rsp)
  xor    %ecx,%ecx
  push   $0x0
  call   <boxfill8@plt>
  lea    -0x2(%rbp),%r10d
  mov    $0x1,%ecx
  mov    %ebp,%esi
  mov    %r10d,%r9d
  mov    $0x1,%r8d
  mov    $0x7,%edx
  xor    %eax,%eax
  mov    %rbx,%rdi
  mov    %r10d,0x14(%rsp)
  movl   $0x1,(%rsp)
  call   <boxfill8@plt>
  xor    %r9d,%r9d
  xor    %r8d,%r8d
  xor    %ecx,%ecx
  mov    $0x8,%edx
  mov    %ebp,%esi
  mov    %rbx,%rdi
  xor    %eax,%eax
  mov    %r13d,(%rsp)
  call   <boxfill8@plt>
  mov    $0x1,%r9d
  mov    %ebp,%esi
  mov    %rbx,%rdi
  mov    $0x1,%ecx
  mov    $0x7,%edx
  xor    %eax,%eax
  mov    %r15d,(%rsp)
  mov    $0x1,%r8d
  call   <boxfill8@plt>
  mov    0x14(%rsp),%r10d
  mov    %ebp,%esi
  mov    %rbx,%rdi
  mov    $0x1,%r8d
  mov    $0xf,%edx
  xor    %eax,%eax
  mov    %r15d,(%rsp)
  mov    %r10d,%r9d
  mov    %r10d,%ecx
  call   <boxfill8@plt>
  xor    %r8d,%r8d
  xor    %edx,%edx
  mov    %r14d,%r9d
  mov    %r14d,%ecx
  mov    %ebp,%esi
  mov    %rbx,%rdi
  xor    %eax,%eax
  mov    %r13d,(%rsp)
  call   <boxfill8@plt>
  lea    -0x3(%rbp),%r9d
  mov    $0x2,%ecx
  mov    %ebp,%esi
  mov    $0x2,%r8d
  mov    $0x8,%edx
  mov    %rbx,%rdi
  xor    %eax,%eax
  mov    %r12d,(%rsp)
  call   <boxfill8@plt>
  lea    -0x4(%rbp),%r9d
  mov    $0x3,%ecx
  mov    %ebp,%esi
  mov    $0x3,%r8d
  mov    $0xc,%edx
  mov    %rbx,%rdi
  xor    %eax,%eax
  movl   $0x14,(%rsp)
  call   <boxfill8@plt>
  mov    0x14(%rsp),%r9d
  mov    %r15d,%r8d
  mov    %ebp,%esi
  mov    $0x1,%ecx
  mov    $0xf,%edx
  mov    %rbx,%rdi
  xor    %eax,%eax
  mov    %r15d,(%rsp)
  call   <boxfill8@plt>
  xor    %ecx,%ecx
  xor    %edx,%edx
  mov    %r14d,%r9d
  mov    %r13d,%r8d
  mov    %ebp,%esi
  mov    %rbx,%rdi
  xor    %eax,%eax
  mov    %r13d,(%rsp)
  call   <boxfill8@plt>
  mov    0x18(%rsp),%r9
  mov    %ebp,%esi
  mov    %rbx,%rdi
  mov    $0x7,%r8d
  mov    $0x4,%ecx
  mov    $0x18,%edx
  xor    %eax,%eax
  call   <putfont8_asc@plt>
  lea    0x0(%rbp,%rbp,4),%eax
  movslq %ebp,%r8
  lea    D2(%rip),%rsi
  cltq
  lea    0xe0(%rsi),%r9
  mov    $0x4f,%ecx
  add    %r8,%rax
  lea    (%rbx,%rax,1),%rdi
  pop    %rax
  pop    %rdx
  nopw   0x0(%rax,%rax,1)
L13:
  xor    %eax,%eax
  jmp    L45
  nopl   0x0(%rax)
L53:
  movzbl (%rsi,%rax,1),%ecx
L45:
  xor    %edx,%edx
  cmp    $0x40,%cl
  je     L6
  mov    $0xf,%edx
  cmp    $0x24,%cl
  je     L6
  cmp    $0x51,%cl
  sete   %dl
  add    $0x7,%edx
L6:
  mov    %dl,-0x15(%rdi,%rax,1)
  add    $0x1,%rax
  cmp    $0x10,%rax
  jne    L53
  add    $0x10,%rsi
  add    %r8,%rdi
  cmp    %r9,%rsi
  je     L30
  movzbl (%rsi),%ecx
  jmp    L13
L30:
  add    $0x18,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

assistant: ```c
void make_window8(unsigned char *buf, int xsize, int ysize, char *title) {
  static char closebtn[14][16] = {"OOOOOOOOOOOOOOO@", "OQQQQQQQQQQQQQ$@", "OQQQQQQQQQQQQQ$@", "OQQQ@@QQQQ@@QQ$@", "OQQQQ@@QQ@@QQQ$@", "OQQQQQ@@@@QQQQ$@", "OQQQQQQ@@QQQQQ$@", "OQQQQQ@@@@QQQQ$@", "OQQQQ@@QQ@@QQQ$@", "OQQQ@@QQQQ@@QQ$@", "OQQQQQQQQQQQQQ$@", "OQQQQQQQQQQQQQ$@", "O$$$$$$$$$$$$$$@", "@@@@@@@@@@@@@@@@"};
  int x, y;
  char c;
  boxfill8(buf, xsize, 8, 0, 0, xsize - 1, 0);
  boxfill8(buf, xsize, 7, 1, 1, xsize - 2, 1);
  boxfill8(buf, xsize, 8, 0, 0, 0, ysize - 1);
  boxfill8(buf, xsize, 7, 1, 1, 1, ysize - 2);
  boxfill8(buf, xsize, 15, xsize - 2, 1, xsize - 2, ysize - 2);
  boxfill8(buf, xsize, 0, xsize - 1, 0, xsize - 1, ysize - 1);
  boxfill8(buf, xsize, 8, 2, 2, xsize - 3, ysize - 3);
  boxfill8(buf, xsize, 12, 3, 3, xsize - 4, 20);
  boxfill8(buf, xsize, 15, 1, ysize - 2, xsize - 2, ysize - 2);
  boxfill8(buf, xsize, 0, 0, ysize - 1, xsize - 1, ysize - 1);
  putfont8_asc(buf, xsize, 24, 4, 7, title);
  for (y = 0; y < 14; y++) {
    for (x = 0; x < 16; x++) {
      c = closebtn[y][x];
      if (c == '@') {
        c = 0;
      } else if (c == '$') {
        c = 15;
      } else if (c == 'Q') {
        c = 8;
      } else {
        c = 7;
      }
      buf[(5 + y) * xsize + (xsize - 21 + x)] = c;
    }
  }
  return;
}
```