7521 - new plan for tests

It's not really manageable to make the fake screen pixel-oriented. Feels
excessive to compare things pixel by pixel when we will mostly be
writing text to screen. It'll also make expected screen assertions
more difficult to manage.

So I'm not sure how to make assertions about pixels for now. Instead
we'll introduce fake screens at draw-grapheme.

1 files changed, 64 insertions, 0 deletions

diff --git a/baremetal/500text-screen.mu b/baremetal/500text-screen.mu
new file mode 100644
index 00000000..525ddb03
--- /dev/null
+++ b/baremetal/500text-screen.mu
@@ -0,0 +1,64 @@
+# Screen primitives for character-oriented output.
+#
+# Unlike the top-level, this text mode has no scrolling.
+
+fn draw-grapheme screen: (addr screen), g: grapheme, x: int, y: int, color: int {
+  {
+    compare screen, 0
+    break-if-!=
+    draw-grapheme-on-real-screen g, x, y, color
+    return
+  }
+  # TODO: fake screen
+}
+
+fn cursor-position screen: (addr screen) -> _/eax: int, _/ecx: int {
+  {
+    compare screen, 0
+    break-if-!=
+    var x/eax: int <- copy 0
+    var y/ecx: int <- copy 0
+    x, y <- cursor-position-on-real-screen
+    return x, y
+  }
+  # TODO: fake screen
+  return 0, 0
+}
+
+fn set-cursor-position screen: (addr screen), x: int, y: int {
+  {
+    compare screen, 0
+    break-if-!=
+    set-cursor-position-on-real-screen x, y
+    return
+  }
+  # TODO: fake screen
+}
+
+fn clear-screen screen: (addr screen) {
+  {
+    compare screen, 0
+    break-if-!=
+    clear-real-screen
+    return
+  }
+  # TODO: fake screen
+}
+
+fn clear-real-screen {
+  var y/eax: int <- copy 0
+  {
+    compare y, 0x300  # 768
+    break-if->=
+    var x/edx: int <- copy 0
+    {
+      compare x, 0x400  # 1024
+      break-if->=
+      pixel-on-real-screen x, y, 0  # black
+      x <- increment
+      loop
+    }
+    y <- increment
+    loop
+  }
+}