Notes for RNG, nw

src/mame/drivers/rungun.cpp

@@ -28,7 +28,7 @@
      - missing sprites and priority
 
    Known Issues:
-     - no dual monitor support is broken
+     - no dual monitor support
      - games seem to think they're in dual-monitor mode when they're not
      - speed in some sets is incorrect (for dual monitors I'm guessing it should
        output alternate frames to alternate monitors, but due to other bugs it
@@ -36,8 +36,6 @@
      - synchronization and other oddities (rungunu doesn't show attract mode)
      - swapped P12 and P34 controls in 4-player mode team selectet (real puzzler)
      - P3 and P4 coin chutes not working in 4-player mode
-
-
      - sprite palettes are not entirely right
 
 *************************************************************************/
@@ -125,6 +123,7 @@ WRITE16_MEMBER(rungun_state::rng_sysregs_w)
 			    bit 1  : disable PSAC2 input?
 			    bit 2  : OBJCHA
 			    bit 3  : enable IRQ 5
+				bit 7-4: base address for 53936 ROM readback.
 			*/
 			m_k055673->k053246_set_objcha_line((data & 0x04) ? ASSERT_LINE : CLEAR_LINE);
 			m_roz_rombase = (data & 0xf0) >> 4;
@@ -166,6 +165,7 @@ INTERRUPT_GEN_MEMBER(rungun_state::rng_interrupt)
 
 READ8_MEMBER(rungun_state::rng_53936_rom_r)
 {
+	// TODO: odd addresses returns ...?
 	UINT32 rom_addr = offset;
 	rom_addr+= (m_roz_rombase)*0x20000;
 	return m_roz_rom[rom_addr];
@@ -412,6 +412,8 @@ static MACHINE_CONFIG_START( rng, rungun_state )
 	MCFG_SOUND_ROUTE(1, "rspeaker", 1.0)
 MACHINE_CONFIG_END
 
+// Older non-US 53936/A13 roms were all returning bad from the mask ROM check. Using the US ROM on non-US reports good therefore I guess that data matches for that
+// across all sets.
 
 ROM_START( rungun )
 	/* main program Europe Version AA  1993, 10.8 */