UEFI and republicans

1 files changed, 27 insertions, 0 deletions

diff --git a/kernel/drivers/gpu/vga_text.c b/kernel/drivers/gpu/vga_text.c
new file mode 100644
index 0000000..e3359c3
--- /dev/null
+++ b/kernel/drivers/gpu/vga_text.c
@@ -0,0 +1,27 @@
+#include <lib.h>
+#include <comus/term.h>
+#include <comus/asm.h>
+#include <comus/memory.h>
+#include <comus/drivers/gpu/vga_text.h>
+
+#define VGA_ADDR 0xB8000
+#define VGA_WIDTH 80
+#define VGA_HEIGHT 25
+static volatile uint16_t *buffer = (uint16_t *)VGA_ADDR;
+
+// color
+static uint8_t fg = 15, bg = 0;
+
+void vga_text_draw_char(char c, uint16_t x, uint16_t y)
+{
+	// output character
+	const size_t index = y * VGA_WIDTH + x;
+	buffer[index] = c | bg << 12 | fg << 8;
+
+	// set cursor position on screen
+	const uint16_t pos = y * VGA_HEIGHT + x;
+	outb(0x3D4, 0x0F);
+	outb(0x3D5, (uint8_t)(pos & 0xFF));
+	outb(0x3D4, 0x0E);
+	outb(0x3D5, (uint8_t)((pos >> 8) & 0xFF));
+}