qemu fb

1 files changed, 68 insertions, 0 deletions

diff --git a/src/arch/amd64/fb.c b/src/arch/amd64/fb.c
new file mode 100644
index 0000000..f27b890
--- /dev/null
+++ b/src/arch/amd64/fb.c
@@ -0,0 +1,68 @@
+#include "bindings.h"
+
+#include <stdint.h>
+#include <stddef.h>
+
+#define PREFERRED_VY 4096
+#define PREFERRED_B 32
+
+uint16_t fb_res_x = 0;
+uint16_t fb_res_y = 0;
+uint16_t fb_res_b = 0;
+
+uint8_t *fb_buffer = NULL;
+
+int fb_init(uint16_t res_x, uint16_t res_y) {
+
+	outw(0x1CE, 0x00);
+	uint16_t i = inw(0x1CF);
+	if (i < 0xB0C0 || i > 0xB0C6) {
+		return -1;	
+	}
+	outw(0x1CF, 0xB0C4);
+	i = inw(0x1CF);
+	/* Disable VBE */
+	outw(0x1CE, 0x04);
+	outw(0x1CF, 0x00);
+	/* Set X resolution to 1024 */
+	outw(0x1CE, 0x01);
+	outw(0x1CF, res_x);
+	/* Set Y resolution to 768 */
+	outw(0x1CE, 0x02);
+	outw(0x1CF, res_y);
+	/* Set bpp to 32 */
+	outw(0x1CE, 0x03);
+	outw(0x1CF, PREFERRED_B);
+	/* Set Virtual Height to stuff */
+	outw(0x1CE, 0x07);
+	outw(0x1CF, PREFERRED_VY);
+	/* Re-enable VBE */
+	outw(0x1CE, 0x04);
+	outw(0x1CF, 0x41);
+
+	uint32_t * text_vid_mem = (uint32_t *)0xA0000;
+	text_vid_mem[0] = 0xA5ADFACE;
+
+	for (uintptr_t fb_offset = 0xE0000000; fb_offset < 0xFF000000; fb_offset += 0x01000000) {
+		/* Enable the higher memory */
+		for (uintptr_t i = fb_offset; i < fb_offset; i += 0x1000) {
+			// todo ident map fb
+		}
+
+		/* Go find it */
+		for (uintptr_t x = fb_offset; x < fb_offset + 0xFF0000; x += 0x1000) {
+			if (((uintptr_t *)x)[0] == 0xA5ADFACE) {
+				fb_buffer = (uint8_t *) x;
+				goto mem_found;
+			}
+		}
+	}
+
+mem_found:
+	
+	fb_res_x = res_x;
+	fb_res_y = res_y;
+	fb_res_b = PREFERRED_B;
+
+	return 0;
+}