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stella
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Some minor optimizations for AR bankswitch scheme. I'm not entirely sure 

how this scheme works, so I have to research further before adding
patch support.  But before that even happens, I need to fix out why
entering the debugger in locking the ROM and eventually crashing Stella.


git-svn-id: svn://svn.code.sf.net/p/stella/code/trunk@1981 8b62c5a3-ac7e-4cc8-8f21-d9a121418aba
This commit is contained in:
stephena 2010-03-30 21:01:33 +00:00
parent 108a807017
commit 779f3bfddb
1 changed files with 34 additions and 32 deletions
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66
src/emucore/CartAR.cxx
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@ -113,7 +113,7 @@ void CartridgeAR::install(System& system)
uInt8 CartridgeAR::peek(uInt16 addr)
{
// Is the "dummy" SC BIOS hotspot for reading a load being accessed?
if(((addr & 0x1FFF) == 0x1850) && (myImageOffset[1] == (3 * 2048)))
if(((addr & 0x1FFF) == 0x1850) && (myImageOffset[1] == (3 << 11)))
{
// Get load that's being accessed (BIOS places load number at 0x80)
uInt8 load = mySystem->peek(0x0080);
@ -152,7 +152,7 @@ uInt8 CartridgeAR::peek(uInt16 addr)
{
if((addr & 0x0800) == 0)
myImage[(addr & 0x07FF) + myImageOffset[0]] = myDataHoldRegister;
else if(myImageOffset[1] != 3 * 2048) // Can't poke to ROM :-)
else if(myImageOffset[1] != (3 << 11)) // Can't poke to ROM :-)
myImage[(addr & 0x07FF) + myImageOffset[1]] = myDataHoldRegister;
myWritePending = false;
}
@ -191,7 +191,7 @@ bool CartridgeAR::poke(uInt16 addr, uInt8)
{
if((addr & 0x0800) == 0)
myImage[(addr & 0x07FF) + myImageOffset[0]] = myDataHoldRegister;
else if(myImageOffset[1] != 3 * 2048) // Can't poke to ROM :-)
else if(myImageOffset[1] != (3 << 11)) // Can't poke to ROM :-)
myImage[(addr & 0x07FF) + myImageOffset[1]] = myDataHoldRegister;
myWritePending = false;
}
@ -220,7 +220,7 @@ void CartridgeAR::bankConfiguration(uInt8 configuration)
// p = ROM Power (0 = enabled, 1 = off.) Only power the ROM if you're
// wanting to access the ROM for multiloads. Otherwise set to 1.
myCurrentBank = configuration & 0x1f; // remember for the bank() method
myCurrentBank = configuration & 0x1F; // remember for the bank() method
// Handle ROM power configuration
myPower = !(configuration & 0x01);
@ -236,60 +236,61 @@ void CartridgeAR::bankConfiguration(uInt8 configuration)
{
case 0:
{
myImageOffset[0] = 2 * 2048;
myImageOffset[1] = 3 * 2048;
myImageOffset[0] = 2 << 11;
myImageOffset[1] = 3 << 11;
break;
}
case 1:
{
myImageOffset[0] = 0 * 2048;
myImageOffset[1] = 3 * 2048;
myImageOffset[0] = 0 ;
myImageOffset[1] = 3 << 11;
break;
}
case 2:
{
myImageOffset[0] = 2 * 2048;
myImageOffset[1] = 0 * 2048;
myImageOffset[0] = 2 << 11;
myImageOffset[1] = 0 ;
break;
}
case 3:
{
myImageOffset[0] = 0 * 2048;
myImageOffset[1] = 2 * 2048;
myImageOffset[0] = 0 ;
myImageOffset[1] = 2 << 11;
break;
}
case 4:
{
myImageOffset[0] = 2 * 2048;
myImageOffset[1] = 3 * 2048;
myImageOffset[0] = 2 << 11;
myImageOffset[1] = 3 << 11;
break;
}
case 5:
{
myImageOffset[0] = 1 * 2048;
myImageOffset[1] = 3 * 2048;
myImageOffset[0] = 1 << 11;
myImageOffset[1] = 3 << 11;
break;
}
case 6:
{
myImageOffset[0] = 2 * 2048;
myImageOffset[1] = 1 * 2048;
myImageOffset[0] = 2 << 11;
myImageOffset[1] = 1 << 11;
break;
}
case 7:
{
myImageOffset[0] = 1 * 2048;
myImageOffset[1] = 2 * 2048;
myImageOffset[0] = 1 << 11;
myImageOffset[1] = 2 << 11;
break;
}
}
myBankChanged = true;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@ -301,27 +302,25 @@ void CartridgeAR::initializeROM()
// almost definitely change
// The scrom.asm code checks a value at offset 109 as follows:
// 0xff -> do a complete jump over the SC BIOS progress bars code
// 0x0 -> show SC BIOS progress bars as normal
ourDummyROMCode[109] = mySettings.getBool("fastscbios") ? 0xff : 0x0;
// 0xFF -> do a complete jump over the SC BIOS progress bars code
// 0x00 -> show SC BIOS progress bars as normal
ourDummyROMCode[109] = mySettings.getBool("fastscbios") ? 0xFF : 0x00;
// The accumulator should contain a random value after exiting the
// SC BIOS code - a value placed in offset 281 will be stored in A
ourDummyROMCode[281] = mySystem->randGenerator().next();
// Initialize ROM with illegal 6502 opcode that causes a real 6502 to jam
for(uInt32 i = 0; i < 2048; ++i)
myImage[3 * 2048 + i] = 0x02;
memset(myImage + (3<<11), 0x02, 2048);
// Copy the "dummy" Supercharger BIOS code into the ROM area
for(uInt32 j = 0; j < sizeof(ourDummyROMCode); ++j)
myImage[3 * 2048 + j] = ourDummyROMCode[j];
memcpy(myImage + (3<<11), ourDummyROMCode, sizeof(ourDummyROMCode));
// Finally set 6502 vectors to point to initial load code at 0xF80A of BIOS
myImage[3 * 2048 + 2044] = 0x0A;
myImage[3 * 2048 + 2045] = 0xF8;
myImage[3 * 2048 + 2046] = 0x0A;
myImage[3 * 2048 + 2047] = 0xF8;
myImage[(3<<11) + 2044] = 0x0A;
myImage[(3<<11) + 2045] = 0xF8;
myImage[(3<<11) + 2046] = 0x0A;
myImage[(3<<11) + 2047] = 0xF8;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@ -409,8 +408,11 @@ int CartridgeAR::bank()
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
int CartridgeAR::bankCount()
{
/*
// TODO - this should depend on ROM size
return 32;
*/
return myNumberOfLoadImages;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@ -424,7 +426,7 @@ bool CartridgeAR::patch(uInt16 address, uInt8 value)
uInt8* CartridgeAR::getImage(int& size)
{
size = myNumberOfLoadImages * 8448;
return &myLoadImages[0];
return myLoadImages;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -