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fix a very paranoid very unlikely nondeterminism in newppu

This commit is contained in:
zeromus 2011-03-18 00:56:49 +00:00
parent 38bca0ae1a
commit 0311add547
1 changed files with 36 additions and 26 deletions
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62
src/ppu.cpp
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@ -2243,10 +2243,10 @@ int FCEUX_PPU_Loop(int skip) {
//int xscroll = ppur.fh;
//render 241 scanlines (including 1 dummy at beginning)
for(int sl=0;sl<241;sl++) {
spr_read.start_scanline();
spr_read.start_scanline();
g_rasterpos = 0;
ppur.status.sl = sl;
g_rasterpos = 0;
ppur.status.sl = sl;
const int yp = sl-1;
ppuphase = PPUPHASE_BG;
@ -2358,19 +2358,21 @@ int FCEUX_PPU_Loop(int skip) {
oamcount=0;
const int spriteHeight = Sprite16?16:8;
for(int i=0;i<64;i++) {
oams[scanslot][oamcount][7] = 0;
uint8* spr = SPRAM+i*4;
if(yp >= spr[0] && yp < spr[0]+spriteHeight) {
//if we already have maxsprites, then this new one causes an overflow,
//set the flag and bail out.
if(oamcount >= 8 && PPUON) {
PPU_status |= 0x20;
if (maxsprites == 8)
break;
if (maxsprites == 8)
break;
}
//just copy some bytes into the internal sprite buffer
for(int j=0;j<4;j++)
oams[scanslot][oamcount][j] = spr[j];
oams[scanslot][oamcount][7] = 1;
//note that we stuff the oam index into [6].
//i need to turn this into a struct so we can have fewer magic numbers
@ -2420,6 +2422,13 @@ int FCEUX_PPU_Loop(int skip) {
uint32 patternNumber = oam[1];
uint32 patternAddress;
//create deterministic dummy fetch pattern
if(!oam[7])
{
patternNumber = 0;
line = 0;
}
//8x16 sprite handling:
if(Sprite16) {
uint32 bank = (patternNumber&1)<<12;
@ -2436,27 +2445,28 @@ int FCEUX_PPU_Loop(int skip) {
patternAddress += line&7;
//garbage nametable fetches
//reset the scroll counter, happens at cycle 304
if (realSprite)
{
if ((sl == 0) && PPUON)
{
if (ppur.status.cycle == 304)
{
runppu(1);
ppur.install_latches();
runppu(1);
}
else
runppu(kFetchTime);
}
else
runppu(kFetchTime);
}
//Dragon's Lair (Europe version mapper 4)
//does not set SpriteON in the beginning but it does
//set the bg on so if using the conditional SpriteON the MMC3 counter
//the counter will never count and no IRQs will be fired so use PPUON
//reset the scroll counter, happens at cycle 304
if (realSprite)
{
if ((sl == 0) && PPUON)
{
if (ppur.status.cycle == 304)
{
runppu(1);
ppur.install_latches();
runppu(1);
}
else
runppu(kFetchTime);
}
else
runppu(kFetchTime);
}
//Dragon's Lair (Europe version mapper 4)
//does not set SpriteON in the beginning but it does
//set the bg on so if using the conditional SpriteON the MMC3 counter
//the counter will never count and no IRQs will be fired so use PPUON
if(((PPU[0]&0x38)!=0x18) && s == 2 && PPUON) { //SpriteON ) {
//(The MMC3 scanline counter is based entirely on PPU A12, triggered on rising edges (after the line remains low for a sufficiently long period of time))
//http://nesdevwiki.org/wiki/index.php/Nintendo_MMC3