Added framebuffer.

Output is now to a framebuffer instead of serial console.

1 files changed, 74 insertions, 0 deletions

diff --git a/kernel/framebuffer.c b/kernel/framebuffer.c
new file mode 100644
index 0000000..220d556
--- /dev/null
+++ b/kernel/framebuffer.c
@@ -0,0 +1,74 @@
+#include "framebuffer.h"
+#include "kernel.h"
+#include "portio.h"
+
+uint16_t framebuffer_color = 0x0700;
+uint8_t framebuffer_x;
+uint8_t framebuffer_y;
+
+void framebuffer_init() {
+	union {uint8_t b[2]; uint16_t w;} pos;
+	
+	outb(0x3d4, 0x0f);
+	inb(0x3d5, pos.b[0]);
+	
+	outb(0x3d4, 0x0e);
+	inb(0x3d5, pos.b[1]);
+	
+	framebuffer_x = pos.w % 80;
+	framebuffer_y = pos.w / 80;
+}
+
+void framebuffer_putchar(char c) {
+	switch(c) {
+		case '\f':
+			framebuffer_clear();
+			break;
+		case '\r':
+			framebuffer_x = 0;
+			break;
+		case '\n':
+			framebuffer_x = 80;
+			break;
+		default:
+			framebuffer[framebuffer_y][framebuffer_x++] = framebuffer_color | c;
+	}
+	if(framebuffer_x == 80) {
+		framebuffer_x = 0;
+		if(framebuffer_y < 24) {
+			framebuffer_y++;
+		} else {
+			framebuffer_scroll();
+		}
+	}
+}
+
+void framebuffer_clear() {
+	for(int y = 0; y < 25; y++) {
+		for(int x = 0; x < 80; x++) {
+			framebuffer[y][x] = framebuffer_color;
+		}
+	}
+	framebuffer_x = framebuffer_y = 0;
+}
+
+void framebuffer_scroll() {
+	for(int y = 0; y < 24; y++) {
+		for(int x = 0; x < 80; x++) {
+			framebuffer[y][x] = framebuffer[y + 1][x];
+		}
+	}
+	for(int x = 0; x < 80; x++) {
+		framebuffer[24][x] = framebuffer_color;
+	}
+}
+
+void framebuffer_move_cursor() {
+	uint16_t pos = framebuffer_y * 80 + framebuffer_x;
+	
+	outb(0x3d4, 0x0f);
+	outb(0x3d5, pos & 0xff);
+	
+	outb(0x3d4, 0x0e);
+	outb(0x3d5, pos >> 8);
+}