From 6e1d10528b1c04c34c57995c85b45448715767f2 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Wed, 11 Oct 2023 15:37:06 +0200
Subject: x86_64: vga: improve text printing code

---
 source/arch/x86_64/src/video/vga/text.cpp | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

(limited to 'source/arch/x86_64/src/video')

diff --git a/source/arch/x86_64/src/video/vga/text.cpp b/source/arch/x86_64/src/video/vga/text.cpp
index 11e3b1a..df61ce6 100644
--- a/source/arch/x86_64/src/video/vga/text.cpp
+++ b/source/arch/x86_64/src/video/vga/text.cpp
@@ -5,25 +5,34 @@
 
 #include <algorithm>
 #include <string_view>
+#include <utility>
 
 namespace teachos::arch::video::vga::text
 {
 
   namespace
   {
-    auto constinit text_buffer = teachos::boot::asm_pointer{boot::vga_buffer_pointer};
+    auto constexpr default_text_buffer_address = 0xb8000;
 
-    auto write(char character, std::byte color) -> void
+    extern "C" std::pair<char, attribute> * vga_buffer_pointer;
+    auto constinit text_buffer = teachos::boot::asm_pointer{vga_buffer_pointer};
+
+    auto write(char code_point, attribute attribute) -> void
     {
       auto & p = *text_buffer;
-      (*p++) = static_cast<std::byte>(character);
-      (*p++) = color;
+      (*p++) = std::pair{code_point, attribute};
     };
   }  // namespace
 
-  auto write(std::string_view text, std::byte color) -> void
+  auto clear(attribute attribute) -> void
+  {
+    *text_buffer = reinterpret_cast<decltype(text_buffer)::pointer>(default_text_buffer_address);
+    std::ranges::generate_n(*text_buffer, 2000, [&]{ return std::pair{' ', attribute}; });
+  }
+
+  auto write(std::string_view code_points, attribute attribute) -> void
   {
-    std::ranges::for_each(text, [&](auto character) { write(character, color); });
+    std::ranges::for_each(code_points, [&](auto code_point) { write(code_point, attribute); });
   }
 
 }  // namespace teachos::arch::video::vga::text
\ No newline at end of file
-- 
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