From b7b97d32cbb6fbc928078ebe3a00714cbbebea86 Mon Sep 17 00:00:00 2001
From: EmulatedSeasons <89668582+EmulatedSeasons@users.noreply.github.com>
Date: Fri, 29 Dec 2023 01:38:34 -0500
Subject: got grub memory map and added to kernel printf

---
 kernel/arch/i386/tmtty.cpp | 34 ++++++++++++++++++----------------
 1 file changed, 18 insertions(+), 16 deletions(-)

(limited to 'kernel/arch/i386/tmtty.cpp')

diff --git a/kernel/arch/i386/tmtty.cpp b/kernel/arch/i386/tmtty.cpp
index 06eb578..d4dc772 100644
--- a/kernel/arch/i386/tmtty.cpp
+++ b/kernel/arch/i386/tmtty.cpp
@@ -10,17 +10,16 @@
 
 static const size_t VGA_WIDTH = 80;
 static const size_t VGA_HEIGHT = 25;
+static uint16_t* const VGA_MEMORY = (uint16_t*) 0xB8000;
 
 size_t terminal_row;
 size_t terminal_column;
 uint8_t terminal_color;
 uint16_t* terminal_buffer;
 
-void terminal_initialize(void) {
+void terminal_clear(void) {
     terminal_row = 0;
     terminal_column = 0;
-    terminal_color = vga_entry_color(VGA_COLOR_WHITE, VGA_COLOR_BLACK);
-    terminal_buffer = (uint16_t*) 0xB8000;
     for (size_t y = 0; y < VGA_HEIGHT; y++) {
         for (size_t x = 0; x < VGA_WIDTH; x++) {
             const size_t i = y * VGA_WIDTH + x;
@@ -29,15 +28,10 @@ void terminal_initialize(void) {
     }
 }
 
-void terminal_clear(void) {
-    terminal_row = 0;
-    terminal_column = 0;
-    for (size_t y = 0; y < VGA_HEIGHT; y++) {
-        for (size_t x = 0; x < VGA_WIDTH; x++) {
-            const size_t i = y * VGA_WIDTH + x;
-            terminal_buffer[i] = vga_entry(' ', terminal_color);
-        }
-    }
+void terminal_initialize(void) {
+    terminal_color = vga_entry_color(VGA_COLOR_WHITE, VGA_COLOR_BLACK);
+    terminal_buffer = VGA_MEMORY;
+    terminal_clear();
 }
 
 void terminal_setcolor(uint8_t color) {
@@ -49,18 +43,26 @@ void terminal_putentryat(char c, uint8_t color, size_t x, size_t y) {
     terminal_buffer[i] = vga_entry(c, color);
 }
 
+void terminal_scroll() {
+    memmove(VGA_MEMORY, (VGA_MEMORY + VGA_WIDTH), (VGA_HEIGHT * VGA_WIDTH) - VGA_WIDTH);
+	memset(VGA_MEMORY + (VGA_WIDTH * VGA_HEIGHT) - VGA_WIDTH, 0x0, VGA_WIDTH * 2);
+	--terminal_row;
+}
+
 void terminal_putchar(char c) {
-    if (c == '\n') {
+    unsigned char uc = c;
+    if (uc == '\n') {
         terminal_column = 0;
-        ++terminal_row;
+        if (terminal_row++ == VGA_HEIGHT)
+			terminal_scroll();
         return;
     }
-    terminal_putentryat(c, terminal_color, terminal_column, terminal_row);
+    terminal_putentryat(uc, terminal_color, terminal_column, terminal_row);
     
     if (++terminal_column == VGA_WIDTH) {
         terminal_column = 0;
         if (++terminal_row == VGA_HEIGHT) {
-            terminal_row = 0;
+            terminal_scroll();
         }
     }
 }
-- 
cgit v1.2.3-70-g09d2