Mermaid (Rock-ola 1982) fix
===========================


* The address $C01b stored the wheater data. Mermaid sometime stored wrong values to this
  address and crashed. Correct data are:

  0x00        => Normal wind
  0x20        => Storm
  0x40        => The flow
  0x60        => Hurricane
  0x80        => End of a level/Next area

* The driver needs also Sprite-to-Sprite collision for the fire in level 2 or whales
  in the later levels. This is only for example something for Kale. He submitted
  in November 2002 a fix for the collision detection.
 


SOURCE: drivers\mermaid.c


Add after static WRITE8_HANDLER( mermaid_AY8910_control_port_w ):

static READ8_HANDLER( mermaid_protection_r )
{
	UINT8 *RAM = memory_region(REGION_CPU1);
	if ((RAM[0xc01b]==0x02 || 0x08 || 0x10) && (activecpu_get_pc()==0x4007))
		RAM[0xc01b] = 0x00;

	/*
         Correct values are:
         0x00 = Normal weather
         0x20 = Storm
         0x40 = The flow
         0x60 = Hurricane
         0x80 = Level end
      */

	return RAM[0xc01b];
}






Add after ROM_START( rougien ):

static DRIVER_INIT( mermaid )
{
	memory_install_read8_handler(0, ADDRESS_SPACE_PROGRAM, 0xc01b, 0xc01b, 0, 0, mermaid_protection_r);
}






Exchanged GAME( 1982, mermaid...) with

GAME( 1982, mermaid, 0, mermaid, mermaid, mermaid, ROT0, "[Sanritsu] Rock-ola", "Mermaid" )




NOTE for Haze:

The comment in src\vidhrdw\mermaid.c line 215 can be deleted.
The selected sprites in Mermaid and Rougien are in all levels correct.

 


(c) 2004  M.A.S.H.