From 9c143d18b951e6312b7d3d16b8e1e0128895ea58 Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Fri, 13 Oct 2023 03:31:36 +0300
Subject: [PATCH] Kernel: Add temporary terminal output before controlling
 terminal

Starting work on getting this boot on real hardware.
---
 kernel/kernel/Debug.cpp  | 33 +++++++++++++++++++++++++++++++++
 kernel/kernel/kernel.cpp | 12 +++++++-----
 2 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/kernel/kernel/Debug.cpp b/kernel/kernel/Debug.cpp
index ed33892251..3fad433704 100644
--- a/kernel/kernel/Debug.cpp
+++ b/kernel/kernel/Debug.cpp
@@ -6,6 +6,10 @@
 #include <kernel/Terminal/TTY.h>
 #include <kernel/Timer/Timer.h>
 
+#include <ctype.h>
+
+extern TerminalDriver* g_terminal_driver;
+
 namespace Debug
 {
 
@@ -64,6 +68,35 @@ namespace Debug
 			return Kernel::Serial::putchar_any(ch);
 		if (Kernel::TTY::is_initialized())
 			return Kernel::TTY::putchar_current(ch);
+
+		if (g_terminal_driver)
+		{
+			static uint32_t col = 0;
+			static uint32_t row = 0;
+
+			if (ch == '\n')
+			{
+				row++;
+				col = 0;
+			}
+			else if (ch == '\r')
+			{
+				col = 0;
+			}
+			else
+			{
+				if (!isprint(ch))
+					ch = '?';
+				g_terminal_driver->putchar_at(ch, col, row, TerminalColor::BRIGHT_WHITE, TerminalColor::BLACK);
+
+				col++;
+				if (col >= g_terminal_driver->width())
+				{
+					row++;
+					col = 0;
+				}
+			}
+		}
 	}
 
 	void print_prefix(const char* file, int line)
diff --git a/kernel/kernel/kernel.cpp b/kernel/kernel/kernel.cpp
index f0430fe45c..3dd2a67c8d 100644
--- a/kernel/kernel/kernel.cpp
+++ b/kernel/kernel/kernel.cpp
@@ -82,6 +82,8 @@ static void parse_command_line()
 extern "C" uint8_t g_userspace_start[];
 extern "C" uint8_t g_userspace_end[];
 
+TerminalDriver* g_terminal_driver = nullptr;
+
 static void init2(void*);
 
 extern "C" void kernel_main()
@@ -114,6 +116,10 @@ extern "C" void kernel_main()
 	PageTable::initialize();
 	dprintln("PageTable initialized");
 
+	g_terminal_driver = VesaTerminalDriver::create();
+	ASSERT(g_terminal_driver);
+	dprintln("VESA initialized");
+
 	Heap::initialize();
 	dprintln("Heap initialzed");
 
@@ -141,11 +147,7 @@ extern "C" void kernel_main()
 		dprintln("Serial devices initialized");
 	}
 
-	TerminalDriver* terminal_driver = VesaTerminalDriver::create();
-	ASSERT(terminal_driver);
-	dprintln("VESA initialized");
-
-	auto vtty = MUST(VirtualTTY::create(terminal_driver));
+	auto vtty = MUST(VirtualTTY::create(g_terminal_driver));
 	dprintln("Virtual TTY initialized");
 
 	MUST(Scheduler::initialize());