Add Framebuffer object

src/hulk/framebuffer.d

@@ -0,0 +1,56 @@
+/**
+ * HULK Framebuffer support.
+ */
+module hulk.framebuffer;
+
+import hos.memory;
+
+/**
+ * Represent a graphical frame buffer.
+ *
+ * TODO: Handle other pixel formats. Currently only ARGB is supported.
+ */
+struct Framebuffer
+{
+    /** Frame buffer base address. */
+    private uint * m_buffer;
+
+    /** Frame buffer width. */
+    private uint m_width;
+
+    /** Frame buffer height. */
+    private uint m_height;
+
+    /** Frame buffer stride. */
+    private uint m_stride;
+
+    /** Number of pixels in the frame buffer (whether visible or not). */
+    private uint m_buffer_size;
+
+    /**
+     * Initialize a frame buffer.
+     *
+     * @param buffer Frame buffer base address.
+     * @param width Frame buffer width.
+     * @param height Frame buffer height.
+     * @param stride Frame buffer stride.
+     */
+    void initialize(uint * buffer, uint width, uint height, uint stride)
+    {
+        m_buffer = buffer;
+        m_width = width;
+        m_height = height;
+        m_stride = stride;
+        m_buffer_size = stride * height;
+    }
+
+    /**
+     * Clear the frame buffer to the given color.
+     *
+     * @param color Color to clear to.
+     */
+    void clear(uint color = 0u)
+    {
+        memset32(m_buffer, color, m_buffer_size);
+    }
+}

src/hulk/hulk.d

@@ -5,9 +5,12 @@ module hulk.hulk;
 
 import hulk.header;
 import hulk.bootinfo;
+import hulk.framebuffer;
 import hos.memory;
 import ldc.attributes;
 
+private __gshared Framebuffer fb;
+
 extern extern(C) __gshared ubyte _hulk_total_size;
 
 @(ldc.attributes.section(".hulk_header"))
@@ -23,9 +26,12 @@ private __gshared Header hulk_header = {
  */
 extern(C) void hulk_start(ulong rdi, ulong rsi, ulong rdx, BootInfo * bootinfo)
 {
+    fb.initialize(bootinfo.fb.buffer, bootinfo.fb.width, bootinfo.fb.height, bootinfo.fb.stride);
+    fb.clear(0xFF8800u);
+
     for (size_t y = 100u; y < 120u; y++)
     {
-        memset32(&bootinfo.fb.buffer[y * bootinfo.fb.stride + 20u], 0xFF8800u, 20u);
+        memset32(&bootinfo.fb.buffer[y * bootinfo.fb.stride + 20u], 0x001199u, 20u);
     }
 
     for (;;)