diff --git a/src/emu/tilemap.cpp b/src/emu/tilemap.cpp
index 1e56fa84d20..083b4b4ef5a 100644
--- a/src/emu/tilemap.cpp
+++ b/src/emu/tilemap.cpp
@@ -897,7 +897,6 @@ u8 tilemap_t::tile_apply_bitmask(const u8 *maskdata, u32 x0, u32 y0, u8 category
 void tilemap_t::configure_blit_parameters(blit_parameters &blit, bitmap_ind8 &priority_bitmap, const rectangle &cliprect, u32 flags, u8 priority, u8 priority_mask)
 {
 	// set the target bitmap
-	assert(priority_bitmap.cliprect().contains(cliprect));
 	blit.priority = &priority_bitmap;
 	blit.cliprect = cliprect;
 
@@ -948,6 +947,8 @@ void tilemap_t::draw_common(screen_device &screen, _BitmapClass &dest, const rec
 
 g_profiler.start(PROFILER_TILEMAP_DRAW);
 	// configure the blit parameters based on the input parameters
+	assert(dest.cliprect().contains(cliprect));
+	assert(screen.cliprect().contains(cliprect));
 	blit_parameters blit;
 	configure_blit_parameters(blit, screen.priority(), cliprect, flags, priority, priority_mask);
 
@@ -1083,6 +1084,8 @@ void tilemap_t::draw_roz_common(screen_device &screen, _BitmapClass &dest, const
 
 g_profiler.start(PROFILER_TILEMAP_DRAW_ROZ);
 	// configure the blit parameters
+	assert(dest.cliprect().contains(cliprect));
+	assert(screen.cliprect().contains(cliprect));
 	blit_parameters blit;
 	configure_blit_parameters(blit, screen.priority(), cliprect, flags, priority, priority_mask);