user: 请从给定的汇编指令推导出C源代码:

```asm
<init_screen>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x20,%rsp
  mov    %rdi,%r12
  mov    %esi,%ebx
  mov    %edx,%ebp
  lea    -0x1(%rsi),%r13d
  lea    -0x1d(%rdx),%eax
  push   %rax
  mov    %r13d,%r9d
  mov    $0x0,%r8d
  mov    $0x0,%ecx
  mov    $0xf,%edx
  call   <fill_box8@plt>
  lea    -0x1c(%rbp),%r8d
  mov    %r8d,(%rsp)
  mov    %r13d,%r9d
  mov    $0x0,%ecx
  mov    $0x8,%edx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <fill_box8@plt>
  lea    -0x1b(%rbp),%r8d
  mov    %r8d,(%rsp)
  mov    %r13d,%r9d
  mov    $0x0,%ecx
  mov    $0x7,%edx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <fill_box8@plt>
  lea    -0x1(%rbp),%eax
  mov    %eax,(%rsp)
  mov    %r13d,%r9d
  lea    -0x1a(%rbp),%r8d
  mov    $0x0,%ecx
  mov    $0x8,%edx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <fill_box8@plt>
  lea    -0x18(%rbp),%r13d
  mov    %r13d,(%rsp)
  mov    $0x3b,%r9d
  mov    %r13d,%r8d
  mov    $0x3,%ecx
  mov    $0x7,%edx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <fill_box8@plt>
  lea    -0x4(%rbp),%r15d
  mov    %r15d,(%rsp)
  mov    $0x2,%r9d
  mov    %r13d,%r8d
  mov    $0x2,%ecx
  mov    $0x7,%edx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <fill_box8@plt>
  mov    %r15d,(%rsp)
  mov    $0x3b,%r9d
  mov    %r15d,%r8d
  mov    $0x3,%ecx
  mov    $0xf,%edx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <fill_box8@plt>
  lea    -0x17(%rbp),%eax
  mov    %eax,%edx
  lea    -0x5(%rbp),%eax
  mov    %eax,(%rsp)
  mov    $0x3b,%r9d
  mov    %edx,0x18(%rsp)
  mov    %edx,%r8d
  mov    $0x3b,%ecx
  mov    $0xf,%edx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <fill_box8@plt>
  sub    $0x3,%ebp
  mov    %ebp,(%rsp)
  mov    $0x3b,%r9d
  mov    %ebp,%r8d
  mov    $0x2,%ecx
  mov    $0x0,%edx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <fill_box8@plt>
  mov    %ebp,(%rsp)
  mov    $0x3c,%r9d
  mov    %r13d,%r8d
  mov    $0x3c,%ecx
  mov    $0x0,%edx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <fill_box8@plt>
  lea    -0x4(%rbx),%eax
  lea    -0x2f(%rbx),%r14d
  mov    %r13d,(%rsp)
  mov    %eax,0x1c(%rsp)
  mov    %eax,%r9d
  mov    %r13d,%r8d
  mov    %r14d,%ecx
  mov    $0xf,%edx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <fill_box8@plt>
  mov    %r15d,(%rsp)
  mov    %r14d,%r9d
  mov    0x18(%rsp),%r8d
  mov    %r14d,%ecx
  mov    $0xf,%edx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <fill_box8@plt>
  mov    %ebp,(%rsp)
  mov    0x1c(%rsp),%r9d
  mov    %ebp,%r8d
  mov    %r14d,%ecx
  mov    $0x7,%edx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <fill_box8@plt>
  lea    -0x3(%rbx),%ecx
  mov    %ebp,(%rsp)
  mov    %ecx,%r9d
  mov    %r13d,%r8d
  mov    $0x7,%edx
  mov    %ebx,%esi
  mov    %r12,%rdi
  call   <fill_box8@plt>
  add    $0x28,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

assistant: ```c
void init_screen(unsigned char *vram, int w, int h) {
  fill_box8(vram, w, (15), 0, 0, w - 1, h - 29);
  fill_box8(vram, w, (8), 0, h - 28, w - 1, h - 28);
  fill_box8(vram, w, (7), 0, h - 27, w - 1, h - 27);
  fill_box8(vram, w, (8), 0, h - 26, w - 1, h - 1);
  fill_box8(vram, w, (7), 3, h - 24, 59, h - 24);
  fill_box8(vram, w, (7), 2, h - 24, 2, h - 4);
  fill_box8(vram, w, (15), 3, h - 4, 59, h - 4);
  fill_box8(vram, w, (15), 59, h - 23, 59, h - 5);
  fill_box8(vram, w, (0), 2, h - 3, 59, h - 3);
  fill_box8(vram, w, (0), 60, h - 24, 60, h - 3);
  fill_box8(vram, w, (15), w - 47, h - 24, w - 4, h - 24);
  fill_box8(vram, w, (15), w - 47, h - 23, w - 47, h - 4);
  fill_box8(vram, w, (7), w - 47, h - 3, w - 4, h - 3);
  fill_box8(vram, w, (7), w - 3, h - 24, w - 3, h - 3);
}
```