vga, again

kernel/drivers/vga/vga.c

@@ -127,4 +127,22 @@ void vga_clear_scrn(uint32_t color) {
 
 uint32_t vga_write(vfs_node_t* node, uint32_t offset, uint32_t size, uint8_t* buf) {
 	return size;
+}
+
+void test_draw_vertical_line(uint32_t x, uint32_t y_start, uint32_t y_end, uint32_t color) {
+    if (framebuffer_address == 0) return;
+
+    uint8_t* fb_bytes = (uint8_t*)framebuffer_address;
+
+    for (uint32_t y = y_start; y < y_end; y++) {
+        if (y >= framebuffer_height) break; 
+
+        uint8_t* row = fb_bytes + (y * framebuffer_pitch);
+
+        uint32_t* pixel_row = (uint32_t*)row;
+
+        if (x < framebuffer_width) {
+            pixel_row[x] = color;
+        }
+    }
 }