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

```asm
<mark_pos>:
  endbr64
  push   %rbp
  push   %rbx
  mov    %edx,%r8d
  test   %ecx,%ecx
  jle    L108
  movslq %edx,%r9
  shl    $0x2,%r9
  mov    %rdi,%rax
  lea    -0x1(%rcx),%edx
  lea    0x8(%rdi,%rdx,8),%r10
  jmp    L232
L219:
  add    $0x8,%rax
  cmp    %r10,%rax
  je     L269
L232:
  mov    %r9,%rdx
  add    (%rax),%rdx
  cmpl   $0x0,(%rdx)
  jne    L219
  movl   $0xa,(%rdx)
  jmp    L219
L269:
  movslq %esi,%rax
  lea    (%rdi,%rax,8),%r10
  mov    %ecx,%r9d
  shl    $0x2,%r9
  mov    $0x0,%eax
  jmp    L261
L76:
  add    $0x4,%rax
  cmp    %r9,%rax
  je     L108
L261:
  mov    %rax,%rdx
  add    (%r10),%rdx
  cmpl   $0x0,(%rdx)
  jne    L76
  movl   $0xa,(%rdx)
  jmp    L76
L108:
  cmp    %r8d,%esi
  mov    %r8d,%eax
  cmovge %esi,%eax
  cmp    %eax,%ecx
  jle    L170
  lea    0x1(%rsi),%eax
  cltq
  movslq %r8d,%r9
  shl    $0x2,%r9
  mov    %r8d,%r11d
  sub    %esi,%r11d
  jmp    L187
L172:
  lea    (%r11,%rax,1),%edx
  cmp    %eax,%edx
  cmovl  %eax,%edx
  add    $0x1,%rax
  add    $0x4,%r9
  cmp    %ecx,%edx
  jge    L170
L187:
  mov    %r9,%rdx
  add    -0x8(%rdi,%rax,8),%rdx
  cmpl   $0x0,(%rdx)
  jne    L172
  movl   $0xa,(%rdx)
  jmp    L172
L170:
  mov    %esi,%r10d
  not    %r10d
  shr    $0x1f,%r10d
  mov    %r8d,%ebx
  not    %ebx
  shr    $0x1f,%ebx
  mov    %esi,%eax
  or     %r8d,%eax
  js     L44
  lea    -0x1(%rsi),%edx
  movslq %edx,%rdx
  movslq %r8d,%r11
  shl    $0x2,%r11
  mov    %r8d,%ebp
  sub    %esi,%ebp
  jmp    L272
L165:
  lea    0x0(%rbp,%rdx,1),%eax
  not    %eax
  shr    $0x1f,%eax
  mov    %edx,%r9d
  not    %r9d
  shr    $0x1f,%r9d
  sub    $0x1,%rdx
  sub    $0x4,%r11
  test   %r9b,%al
  je     L44
L272:
  mov    %r11,%rax
  add    0x8(%rdi,%rdx,8),%rax
  cmpl   $0x0,(%rax)
  jne    L165
  movl   $0xa,(%rax)
  jmp    L165
L44:
  cmp    %esi,%ecx
  jle    L123
  test   %bl,%bl
  je     L123
  lea    0x1(%rsi),%edx
  movslq %edx,%rdx
  movslq %r8d,%r9
  shl    $0x2,%r9
  lea    (%r8,%rsi,1),%ebx
  jmp    L140
L277:
  mov    %ebx,%eax
  sub    %edx,%eax
  not    %eax
  shr    $0x1f,%eax
  cmp    %edx,%ecx
  setg   %r11b
  add    $0x1,%rdx
  sub    $0x4,%r9
  test   %al,%r11b
  je     L123
L140:
  mov    %r9,%rax
  add    -0x8(%rdi,%rdx,8),%rax
  cmpl   $0x0,(%rax)
  jne    L277
  movl   $0xa,(%rax)
  jmp    L277
L123:
  cmp    %r8d,%ecx
  jle    L72
  test   %r10b,%r10b
  je     L72
  lea    -0x1(%rsi),%eax
  cltq
  movslq %r8d,%r9
  shl    $0x2,%r9
  lea    (%rsi,%r8,1),%r11d
  jmp    L293
L58:
  mov    %r11d,%edx
  sub    %eax,%edx
  cmp    %ecx,%edx
  setl   %r10b
  mov    %eax,%edx
  not    %edx
  shr    $0x1f,%edx
  sub    $0x1,%rax
  add    $0x4,%r9
  test   %dl,%r10b
  je     L72
L293:
  mov    %r9,%rdx
  add    0x8(%rdi,%rax,8),%rdx
  cmpl   $0x0,(%rdx)
  jne    L58
  movl   $0xa,(%rdx)
  jmp    L58
L72:
  movslq %esi,%rsi
  movslq %r8d,%r8
  mov    (%rdi,%rsi,8),%rax
  movl   $0x14,(%rax,%r8,4)
  mov    $0x0,%eax
  pop    %rbx
  pop    %rbp
  ret
```

assistant: ```c
int mark_pos(int **board, int x, int y, int q) {
  int i = 0, j = 0;
  int flag = 0;
  for (i = 0; i < q; i++) {
    j = y;
    if (board[i][j] == 0) {
      board[i][j] = 10;
    }
  }
  for (j = 0; j < q; j++) {
    i = x;
    if (board[i][j] == 0) {
      board[i][j] = 10;
    }
  }
  for (i = x, j = y; i < q && j < q; i++, j++) {
    if (board[i][j] == 0) {
      board[i][j] = 10;
    }
  }
  for (i = x, j = y; i >= 0 && j >= 0; i--, j--) {
    if (board[i][j] == 0) {
      board[i][j] = 10;
    }
  }
  for (i = x, j = y; i < q && j >= 0; i++, j--) {
    if (board[i][j] == 0) {
      board[i][j] = 10;
    }
  }
  for (i = x, j = y; i >= 0 && j < q; i--, j++) {
    if (board[i][j] == 0) {
      board[i][j] = 10;
    }
  }
  board[x][y] = 20;
  return 0;
}
```