organize source files into separate directories

src/drivers/screen.c

@@ -0,0 +1,93 @@
+// screen.c
+#include "../include/screen.h"
+#include "../include/string.h"
+
+static size_t terminal_row;
+static size_t terminal_column;
+static uint8_t terminal_color;
+static uint16_t* terminal_buffer;
+
+inline uint8_t vga_entry_color(enum vga_color fg, enum vga_color bg) 
+{
+        return fg | bg << 4;
+}
+
+inline uint16_t vga_entry(unsigned char uc, uint8_t color) 
+{
+        return (uint16_t) uc | (uint16_t) color << 8;
+}
+
+void terminal_initialize(void) 
+{
+        terminal_row = 0;
+        terminal_column = 0;
+        terminal_color = vga_entry_color(VGA_COLOR_LIGHT_GREY, 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 index = y * VGA_WIDTH + x;
+                        terminal_buffer[index] = vga_entry(' ', terminal_color);
+                }
+        }
+}
+
+void terminal_setcolor(uint8_t color) 
+{
+        terminal_color = color;
+}
+
+void terminal_putentryat(char c, uint8_t color, size_t x, size_t y) 
+{
+        const size_t index = y * VGA_WIDTH + x;
+        terminal_buffer[index] = vga_entry(c, color);
+}
+
+void terminal_scroll(void)
+{
+        for (size_t y = 0; y < VGA_HEIGHT - 1; y++) {
+                for (size_t x = 0; x < VGA_WIDTH; x++) {
+                        const size_t index_from = (y + 1) * VGA_WIDTH + x;
+                        const size_t index_to = y * VGA_WIDTH + x;
+                        terminal_buffer[index_to] = terminal_buffer[index_from];
+                }
+        }
+        for (size_t x = 0; x < VGA_WIDTH; x++) {
+                const size_t index = (VGA_HEIGHT - 1) * VGA_WIDTH + x;
+                terminal_buffer[index] = vga_entry(' ', terminal_color);
+        }
+        terminal_row = VGA_HEIGHT - 1;
+        terminal_column = 0;
+}
+
+void terminal_putchar(char c)
+{
+	if(c != '\n')
+		terminal_putentryat(c, terminal_color, terminal_column, terminal_row);
+
+	if (++terminal_column >= VGA_WIDTH){
+                terminal_column = 0;
+        	if (++terminal_row >= VGA_HEIGHT)
+                	terminal_scroll();
+	}
+	if(terminal_row >= VGA_HEIGHT){
+		terminal_scroll();
+	}
+
+	if(c == '\n')
+	{
+		terminal_column = 0;
+		terminal_row++;
+	}
+
+}
+
+void terminal_write(const char* data, size_t size) 
+{
+        for (size_t i = 0; i < size; i++)
+                terminal_putchar(data[i]);
+}
+
+void terminal_writestring(const char* data) 
+{
+        terminal_write(data, strlen(data));
+}