tvgames/xavix.cpp: Document ekara alternate input dip (#14866)

BGM Down/Up buttons not affected, surprisingly.

Author: einstein95

src/mame/tvgames/xavix.cpp

@@ -854,25 +854,38 @@ INPUT_PORTS_END
 static INPUT_PORTS_START( ekara )
 	PORT_INCLUDE(xavix)
 
+	PORT_MODIFY("IN0")
+	PORT_DIPNAME( 0x80, 0x00, "Alternate Input Mapping" )
+	PORT_DIPSETTING(    0x00, DEF_STR( Off ) )
+	PORT_DIPSETTING(    0x80, DEF_STR( On ) )
+
 	PORT_MODIFY("IN1")
 	PORT_BIT( 0x01, IP_ACTIVE_HIGH, IPT_CUSTOM ) PORT_READ_LINE_MEMBER(FUNC(xavix_ekara_state::ekara_multi0_r))
 	PORT_BIT( 0x02, IP_ACTIVE_HIGH, IPT_CUSTOM ) PORT_READ_LINE_MEMBER(FUNC(xavix_ekara_state::ekara_multi1_r))
 
 	PORT_BIT( 0x40, IP_ACTIVE_HIGH, IPT_POWER_OFF ) PORT_NAME("Power Switch") // pressing this will turn the game off.
 
 	PORT_START("EXTRA0")
-	PORT_BIT( 0x01, IP_ACTIVE_HIGH, IPT_BUTTON3 ) PORT_NAME("Echo")
-	PORT_BIT( 0x02, IP_ACTIVE_HIGH, IPT_BUTTON4 ) PORT_NAME("Effects")
-	PORT_BIT( 0x04, IP_ACTIVE_HIGH, IPT_JOYSTICK_DOWN ) PORT_NAME("Key Down")
-	PORT_BIT( 0x08, IP_ACTIVE_HIGH, IPT_JOYSTICK_UP ) PORT_NAME("Key Up")
+	PORT_BIT( 0x01, IP_ACTIVE_HIGH, IPT_BUTTON3 ) PORT_NAME("Echo")				PORT_CONDITION("IN0", 0x80, EQUALS, 0x00)
+	PORT_BIT( 0x02, IP_ACTIVE_HIGH, IPT_BUTTON4 ) PORT_NAME("Effects")			PORT_CONDITION("IN0", 0x80, EQUALS, 0x00)
+	PORT_BIT( 0x04, IP_ACTIVE_HIGH, IPT_JOYSTICK_DOWN ) PORT_NAME("Key Down")	PORT_CONDITION("IN0", 0x80, EQUALS, 0x00)
+	PORT_BIT( 0x08, IP_ACTIVE_HIGH, IPT_JOYSTICK_UP ) PORT_NAME("Key Up")		PORT_CONDITION("IN0", 0x80, EQUALS, 0x00)
 	PORT_BIT( 0x10, IP_ACTIVE_HIGH, IPT_BUTTON5 ) PORT_NAME("BGM Down")
 	PORT_BIT( 0x20, IP_ACTIVE_HIGH, IPT_BUTTON6 ) PORT_NAME("BGM Up")
-	PORT_BIT( 0x40, IP_ACTIVE_HIGH, IPT_BUTTON7 ) PORT_NAME("Tempo Down")
-	PORT_BIT( 0x80, IP_ACTIVE_HIGH, IPT_BUTTON8 ) PORT_NAME("Tempo Up")
+	PORT_BIT( 0x40, IP_ACTIVE_HIGH, IPT_BUTTON7 ) PORT_NAME("Tempo Down")		PORT_CONDITION("IN0", 0x80, EQUALS, 0x00)
+	PORT_BIT( 0x80, IP_ACTIVE_HIGH, IPT_BUTTON8 ) PORT_NAME("Tempo Up")			PORT_CONDITION("IN0", 0x80, EQUALS, 0x00)
+	PORT_BIT( 0x01, IP_ACTIVE_HIGH, IPT_BUTTON1 ) PORT_NAME("Select")			PORT_CONDITION("IN0", 0x80, EQUALS, 0x80)
+	PORT_BIT( 0x02, IP_ACTIVE_HIGH, IPT_BUTTON2 ) PORT_NAME("Cancel")			PORT_CONDITION("IN0", 0x80, EQUALS, 0x80)
+	PORT_BIT( 0x04, IP_ACTIVE_HIGH, IPT_BUTTON7 ) PORT_NAME("Tempo Down")		PORT_CONDITION("IN0", 0x80, EQUALS, 0x80)
+	PORT_BIT( 0x08, IP_ACTIVE_HIGH, IPT_BUTTON8 ) PORT_NAME("Tempo Up")			PORT_CONDITION("IN0", 0x80, EQUALS, 0x80)
+	PORT_BIT( 0x40, IP_ACTIVE_HIGH, IPT_JOYSTICK_DOWN ) PORT_NAME("Key Down")	PORT_CONDITION("IN0", 0x80, EQUALS, 0x80)
+	PORT_BIT( 0x80, IP_ACTIVE_HIGH, IPT_JOYSTICK_UP ) PORT_NAME("Key Up")		PORT_CONDITION("IN0", 0x80, EQUALS, 0x80)
 
 	PORT_START("EXTRA1")
-	PORT_BIT( 0x01, IP_ACTIVE_HIGH, IPT_BUTTON1 ) PORT_NAME("Select")
-	PORT_BIT( 0x02, IP_ACTIVE_HIGH, IPT_BUTTON2 ) PORT_NAME("Cancel")
+	PORT_BIT( 0x01, IP_ACTIVE_HIGH, IPT_BUTTON1 ) PORT_NAME("Select")			PORT_CONDITION("IN0", 0x80, EQUALS, 0x00)
+	PORT_BIT( 0x02, IP_ACTIVE_HIGH, IPT_BUTTON2 ) PORT_NAME("Cancel")			PORT_CONDITION("IN0", 0x80, EQUALS, 0x00)
+	PORT_BIT( 0x01, IP_ACTIVE_HIGH, IPT_BUTTON3 ) PORT_NAME("Echo")				PORT_CONDITION("IN0", 0x80, EQUALS, 0x80)
+	PORT_BIT( 0x02, IP_ACTIVE_HIGH, IPT_BUTTON4 ) PORT_NAME("Effects")			PORT_CONDITION("IN0", 0x80, EQUALS, 0x80)
 	PORT_BIT( 0x3c, IP_ACTIVE_HIGH, IPT_UNUSED )
 	// no 40/80 due to multiplexer code
 INPUT_PORTS_END