konami/hexion.cpp: Fixed tile invalidation range when 16-byte clear is not four-byte aligned.

cuavas · cuavas · commit 4609405c8bdf · 2024-02-03T14:56:00.000+11:00
diff --git a/src/mame/konami/hexion.cpp b/src/mame/konami/hexion.cpp
@@ -255,11 +255,11 @@ void hexion_state::bankswitch_w(uint8_t data)
 		else
 		{
 			const uint8_t bank = m_pmcram[4] & 1;
-			const uint16_t offset = get_u16le(&m_pmcram[2]);
+			const unsigned offset = get_u16le(&m_pmcram[2]);
 			for (int i = 0; 16 > i; ++i)
 				m_vram[bank][(offset + i) & 0x1fff] = 0;
-			for (int i = 0; 4 > i; ++i)
-				m_bg_tilemap[bank]->mark_tile_dirty(((offset >> 2) + i) & 0x07ff);
+			for (unsigned i = offset & ~3U; (offset + 16) > i; i += 4)
+				m_bg_tilemap[bank]->mark_tile_dirty((i >> 2) & 0x07ff);
 		}
 	}
 

Original file line number	Diff line number	Diff line change
`@@ -255,11 +255,11 @@ void hexion_state::bankswitch_w(uint8_t data)`
`255`	`255`	`else`
`256`	`256`	`{`
`257`	`257`	`const uint8_t bank = m_pmcram[4] & 1;`
`258`		`- const uint16_t offset = get_u16le(&m_pmcram[2]);`
	`258`	`+ const unsigned offset = get_u16le(&m_pmcram[2]);`
`259`	`259`	`for (int i = 0; 16 > i; ++i)`
`260`	`260`	`m_vram[bank][(offset + i) & 0x1fff] = 0;`
`261`		`- for (int i = 0; 4 > i; ++i)`
`262`		`- m_bg_tilemap[bank]->mark_tile_dirty(((offset >> 2) + i) & 0x07ff);`
	`261`	`+ for (unsigned i = offset & ~3U; (offset + 16) > i; i += 4)`
	`262`	`+ m_bg_tilemap[bank]->mark_tile_dirty((i >> 2) & 0x07ff);`
`263`	`263`	`}`
`264`	`264`	`}`
`265`	`265`