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- Patched out a decrementer loop that was preventing Spikeout from starting up.

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This commit is contained in:
Bart Trzynadlowski 2011-07-20 06:20:40 +00:00
parent 097b87e3c9
commit 12693a70f6
1 changed files with 24 additions and 5 deletions
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29
Src/Model3/Model3.cpp
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@ -502,8 +502,11 @@ void CModel3::WriteInputs(unsigned reg, UINT8 data)
/******************************************************************************
Model 3 Security Device
The security device is present in some games. Virtual On 2 reads tile pattern
data from it.
The security device is present in some games. Virtual On and Dirt Devils read
tile pattern data from it. Spikeout calls a routine at PC=0x6FAC8 that writes/
reads the security device and, if the return value in R3 is 0, prints "ILLEGAL
ROM" and locks the game. Our habit of returning all 1's for unknown reads
seems to help avoid this.
******************************************************************************/
static const UINT16 spikeoutSecurity[] =
@ -639,7 +642,7 @@ UINT32 CModel3::ReadSecurity(unsigned reg)
void CModel3::WriteSecurity(unsigned reg, UINT32 data)
{
DebugLog("Security write: reg=%X, data=%08X\n", reg, data);
DebugLog("Security write: reg=%X, data=%08X (PC=%08X, LR=%08X)\n", reg, data, ppc_get_pc(), ppc_get_lr());
}
@ -2097,6 +2100,22 @@ void CModel3::Patch(void)
*(UINT32 *) &crom[0x535560] = 0x60000000; // decrementer loop
}
else if (!strcmp(Game->id, "spikeout"))
{
/*
* Decrementer loop at 0x31994 seems to work until a few frames into
* the attract mode and game, at which point a very large value is
* loaded into the decrementer and locks up the CPU (the usual
* decrementer problem). "Insert Coin" keeps flashing because it is
* managed via an IRQ, evidently.
*
* 0x00031994: 0x7C9602A6 mfspr r4,dec
* 0x00031998: 0x2C040000 cmpi cr0,0,r4,0x0000
* 0x0003199C: 0x41A0FFF8 bt cr0[lt],0x00031994
*/
*(UINT32 *) &crom[0x600000+0x3199C] = 0x60000000;
}
}
// Reverses all aligned 16-bit words, thereby switching their endianness (assumes buffer size is divisible by 2)
@ -2346,8 +2365,8 @@ CModel3::~CModel3(void)
//Dump("vrom", vrom, 0x4000000, TRUE, FALSE);
//Dump("crom", crom, 0x800000, TRUE, FALSE);
//Dump("bankedCrom", &crom[0x800000], 0x7000000, TRUE, FALSE);
Dump("soundROM", soundROM, 0x80000, FALSE, TRUE);
Dump("sampleROM", sampleROM, 0x800000, FALSE, TRUE);
//Dump("soundROM", soundROM, 0x80000, FALSE, TRUE);
//Dump("sampleROM", sampleROM, 0x800000, FALSE, TRUE);
#endif
if (memoryPool != NULL)