1 files changed, 114 insertions, 0 deletions
diff --git a/src/kernel/core/monitor.cpp b/src/kernel/core/monitor.cpp
new file mode 100644
index 0000000..ba2a6df
--- /dev/null
+++ b/src/kernel/core/monitor.cpp
@@ -0,0 +1,114 @@
+#include "monitor.h"
+#include "sys.h"
+
+#include "mem/mem.h"
+
+static int cursor_x = 0, cursor_y = 0;
+static uint16_t *video_memory = (uint16_t*)((size_t)K_HIGHHALF_ADDR + 0xB8000);
+
+static uint8_t attribute = 0x07; // 0 = background = black, 7 = foreground = white
+
+/*	For internal use only. Tells hardware to move the cursor at (cursor_x, cursor_y). */
+static void move_cursor() {
+	uint16_t cursor_location = cursor_y * 80 + cursor_x;
+	outb(0x3D4, 14);	//Sending high cursor byte
+	outb(0x3D5, cursor_location >> 8);
+	outb(0x3D4, 15);	//Sending high cursor byte
+	outb(0x3D5, cursor_location);
+}
+
+/*	For internal use only. Scrolls everything up one line. */
+static void scroll() {
+	uint16_t blank = (attribute << 8) | 0x20;
+
+	if (cursor_y >= 25) {
+		int i;
+		for (i = 0; i < 80*24; i++) {
+			video_memory[i] = video_memory[i+80];
+		}
+		for (i = 80*24; i < 80*25; i++) {
+			video_memory[i] = blank;
+		}
+		cursor_y = 24;
+	}
+}
+
+/*	Put one character on the screen. This function handles special characters \b, \t, \r and  \n. */
+void monitor_put(char c) {
+	if (c == '\b' && cursor_x) {	//Backspace
+		cursor_x--;
+	} else if (c == '\t') {	//Tab
+		cursor_x = (cursor_x + 8) & ~(8 - 1);
+	} else if (c == '\r') {	//Carriage return
+		cursor_x = 0;
+	} else if (c == '\n') {	//New line
+		cursor_x = 0;
+		cursor_y++;
+	} else if (c >= ' ') {	//Any printable character
+		video_memory[cursor_y * 80 + cursor_x] = c | (attribute << 8);
+		cursor_x++;
+	}
+	if (cursor_x >= 80) {
+		cursor_x = 0;
+		cursor_y++;
+	}
+
+	scroll();
+	move_cursor();
+}
+
+/* Clears the screen and moves cursor to (0,0) (top left corner) */
+void monitor_clear() {
+	uint16_t blank = (attribute << 8) | 0x20;
+
+	int i;
+
+	for (i = 0; i < 80*25; i++) {
+		video_memory[i] = blank;
+	}
+
+	cursor_x = 0; cursor_y = 0;
+	move_cursor();
+}
+
+/* Writes a string to the monitor */
+void monitor_write(char *s) {
+	while (*s) {
+		monitor_put(*(s++));
+	}
+}
+
+/* Writes a number in hexadecimal notation to the monitor */
+void monitor_writeHex(uint32_t v) {
+	int i;
+
+	monitor_put('0'); monitor_put('x');
+	char hexdigits[] = "0123456789abcdef";
+
+	for (i = 0; i < 8; i++) {
+		monitor_put(hexdigits[v >> 28]);
+		v = v << 4;
+	}
+}
+
+/* Writes a number in decimal notation to the monitor */
+void monitor_writeDec(uint32_t v) {
+	if (v == 0) {
+		monitor_put('0');
+		return;
+	}
+
+	char numbers[] = "0123456789";
+	while (v > 0) {
+		int order = 1, no = 1;
+		while (v / order > 0) order *= 10;
+		order /= 10;
+		monitor_put(numbers[v / order]);
+		v = v - (v / order * order);
+		while (v / no > 0) no *= 10;
+		while (no < order) {
+			monitor_put('0');
+			no *= 10;
+		}
+	}
+}