# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1541288600 -3600
# Node ID 3783422f5bdc58b409ca29021e046f3406989960
# Parent  254ee12221e275699dd9252be7b494bc13b4c7f3
Introduced a function to wait for the end of the visible region.

diff -r 254ee12221e2 -r 3783422f5bdc examples/vga/main.c
--- a/examples/vga/main.c	Sat Nov 03 14:05:05 2018 +0100
+++ b/examples/vga/main.c	Sun Nov 04 00:43:20 2018 +0100
@@ -164,6 +164,7 @@
                              x, y, 0x8c, 1);
 
                 wait(delay);
+                vga_wait_visible();
 
                 /* Copy to the display from the store, restoring the original
                    background. */
@@ -335,7 +336,7 @@
 
     /* Move a sprite around on the screen with a delay between each movement. */
 
-    animate(1 << 21);
+    animate(1 << 18);
 }
 
 
diff -r 254ee12221e2 -r 3783422f5bdc include/vga_display.h
--- a/include/vga_display.h	Sat Nov 03 14:05:05 2018 +0100
+++ b/include/vga_display.h	Sun Nov 04 00:43:20 2018 +0100
@@ -84,6 +84,10 @@
 void vga_configure_zero_channel(int channel, int int_num, int initiating,
                                 uint32_t output);
 
+/* Access-related operations. */
+
+void vga_wait_visible(void);
+
 /* Interrupt handlers. */
 
 void vga_interrupt_handler(void);
diff -r 254ee12221e2 -r 3783422f5bdc lib/vga_display.c
--- a/lib/vga_display.c	Sat Nov 03 14:05:05 2018 +0100
+++ b/lib/vga_display.c	Sun Nov 04 00:43:20 2018 +0100
@@ -243,6 +243,16 @@
 
 
 
+/* Wait for the visible region to be completed. */
+
+void vga_wait_visible(void)
+{
+    while (((volatile void (*)()) vga_display.state_handler) == visible_active)
+        __asm__ __volatile__("wait");
+}
+
+
+
 /* Display state machine interrupt handler. */
 
 void vga_interrupt_handler(void)