1 files changed, 22 insertions, 0 deletions
diff --git a/arch/x86_64/src/video/vga/text.cpp b/arch/x86_64/src/video/vga/text.cpp
index a613c3b..c14de16 100644
--- a/arch/x86_64/src/video/vga/text.cpp
+++ b/arch/x86_64/src/video/vga/text.cpp
@@ -13,6 +13,8 @@ namespace teachos::arch::video::vga::text
   namespace
   {
     auto constexpr default_text_buffer_address = 0xb8000;
+    auto constexpr default_text_buffer_width = 80;
+    auto constexpr default_text_buffer_height = 25;
 
     extern "C" std::pair<char, attribute> * vga_buffer_pointer;
     auto constinit text_buffer = teachos::memory::asm_pointer{vga_buffer_pointer};
@@ -32,6 +34,26 @@ namespace teachos::arch::video::vga::text
     crtc::data_port::write(vga::crtc::data_port::read() | cursor_disable_byte);
   }
 
+  auto newline() -> void
+  {
+    auto base = reinterpret_cast<decltype(text_buffer)::pointer>(default_text_buffer_address);
+    auto & raw_buffer = *text_buffer;
+    auto current_line = (raw_buffer - base) / default_text_buffer_width;
+    auto next_line = current_line + 1;
+
+    if (next_line >= default_text_buffer_height)
+    {
+      auto begin = base + default_text_buffer_width;
+      auto end = base + default_text_buffer_width * default_text_buffer_height;
+      std::ranges::move(begin, end, base);
+      raw_buffer = base + current_line * default_text_buffer_width;
+    }
+    else
+    {
+      raw_buffer = base + next_line * default_text_buffer_width;
+    }
+  }
+
   auto write_char(char code_point, attribute attribute) -> void
   {
     auto & p = *text_buffer;