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[SNES]: Made the OAM address reset more accurate.

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This commit is contained in:
Angelo Salese 2009-08-15 14:03:21 +00:00
parent 6f63ec3117
commit 5684f6198d
1 changed files with 19 additions and 8 deletions
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27
src/mame/machine/snes.c
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@ -103,11 +103,20 @@ static TIMER_CALLBACK( snes_hirq_tick_callback )
snes_hirq_tick(machine);
}
static TIMER_CALLBACK( snes_scanline_tick )
static TIMER_CALLBACK( snes_reset_oam_address )
{
// make sure we're in the 65816's context since we're messing with the OAM and stuff
const address_space *space = cputag_get_address_space(machine, "maincpu", ADDRESS_SPACE_PROGRAM);
if(!(snes_ram[INIDISP]&0x80)) //Reset OAM address, byuu says it happens at H=10
{
memory_write_byte(space, OAMADDL, snes_ppu.oam.saved_address_low ); /* Reset oam address */
memory_write_byte(space, OAMADDH, snes_ppu.oam.saved_address_high );
}
}
static TIMER_CALLBACK( snes_scanline_tick )
{
/* Increase current line - we want to latch on this line during it, not after it */
snes_ppu.beam.current_vert = video_screen_get_vpos(machine->primary_screen);
@ -157,11 +166,8 @@ static TIMER_CALLBACK( snes_scanline_tick )
/* Start of VBlank */
if( snes_ppu.beam.current_vert == snes_ppu.beam.last_visible_line )
{
if(!(snes_ram[INIDISP]&0x80))
{
memory_write_byte(space, OAMADDL, snes_ppu.oam.saved_address_low ); /* Reset oam address */
memory_write_byte(space, OAMADDH, snes_ppu.oam.saved_address_high );
}
timer_set(machine, video_screen_get_time_until_pos(machine->primary_screen, snes_ppu.beam.current_vert, 10), NULL, 0, snes_reset_oam_address);
snes_ram[HVBJOY] |= 0x81; /* Set vblank bit to on & indicate controllers being read */
snes_ram[RDNMI] |= 0x80; /* Set NMI occured bit */
@ -664,8 +670,8 @@ WRITE8_HANDLER( snes_w_io )
// APU is mirrored from 2140 to 217f
if (offset >= APU00 && offset < WMDATA)
{
// printf("816: %02x to APU @ %d\n", data, offset&3);
spc_port_in[offset & 0x3] = data;
// printf("816: %02x to APU @ %d\n", data, offset&3);
spc_port_in[offset & 0x3] = data;
cpuexec_boost_interleave(space->machine, attotime_zero, ATTOTIME_IN_USEC(20));
return;
}
@ -674,6 +680,11 @@ WRITE8_HANDLER( snes_w_io )
switch( offset )
{
case INIDISP: /* Initial settings for screen */
if((snes_ram[INIDISP] & 0x80) && (!(data & 0x80))) //a 1->0 force blank transition causes a reset OAM address
{
memory_write_byte(space, OAMADDL, snes_ppu.oam.saved_address_low );
memory_write_byte(space, OAMADDH, snes_ppu.oam.saved_address_high );
}
break;
case OBSEL: /* Object size and data area designation */
snes_ppu.layer[4].data = ((data & 0x3) * 0x2000) << 1;