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Handle creation of 2K/Sub2K and all other cart types separately. 

This simplifies the logic in both cases, and fixes a few corner cases.
This commit is contained in:
Stephen Anthony 2020-06-11 19:04:39 -02:30
parent cb790081a2
commit dc3324e083
2 changed files with 47 additions and 68 deletions
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24
src/emucore/Cart2K.cxx
View File

@ -24,4 +24,28 @@ Cartridge2K::Cartridge2K(const ByteBuffer& image, size_t size,
size_t bsSize)
: CartridgeEnhanced(image, size, md5, settings, bsSize)
{
// When creating a 2K cart, we always initially create a buffer of size 2_KB
// Sometimes we only use a portion of that buffer; we check for that now
// Size can be a maximum of 2K
size = std::min(size, bsSize);
// Set image size to closest power-of-two for the given size
mySize = 1; myBankShift = 0;
while(mySize < size)
{
mySize <<= 1;
myBankShift++;
}
// Handle cases where ROM is smaller than the page size
// It's much easier to do it this way rather than changing the page size
if(mySize < System::PAGE_SIZE)
{
// Manually 'mirror' the ROM image into the buffer
for(size_t i = 0; i < System::PAGE_SIZE; i += mySize)
std::copy_n(image.get(), mySize, myImage.get() + i);
mySize = System::PAGE_SIZE;
myBankShift = 6;
}
}

61
src/emucore/CartEnhanced.cxx
View File

@ -27,8 +27,7 @@ CartridgeEnhanced::CartridgeEnhanced(const ByteBuffer& image, size_t size,
{
// ROMs are not always at the 'legal' size for their associated
// bankswitching scheme; here we deal with the differing sizes
if(size != bsSize)
{
// Is the ROM too large? If so, we cap it
if(size > bsSize)
{
@ -36,35 +35,8 @@ CartridgeEnhanced::CartridgeEnhanced(const ByteBuffer& image, size_t size,
buf << "ROM larger than expected (" << size << " > " << bsSize
<< "), truncating " << (size - bsSize) << " bytes\n";
Logger::info(buf.str());
size = bsSize;
}
// Set image size to closest power-of-two for the given size
// This only applies for sizes less than the standard bank size
if(size < 4_KB)
{
mySize = 1; myBankShift = 0;
while(mySize < size)
{
mySize <<= 1;
myBankShift++;
}
}
else
// Make sure to use size defined by the bankswitching scheme
mySize = std::max(size, bsSize);
// Initialize ROM with all 0's, to fill areas that the ROM may not cover
size_t bufSize = std::max<size_t>(mySize, System::PAGE_SIZE);
myImage = make_unique<uInt8[]>(bufSize);
std::fill_n(myImage.get(), bufSize, 0);
// Handle cases where ROM is smaller than the page size
// It's much easier to do it this way rather than changing the page size
if(mySize >= System::PAGE_SIZE)
{
if(size < mySize)
else if(size < mySize)
{
ostringstream buf;
buf << "ROM smaller than expected (" << mySize << " > " << size
@ -72,33 +44,16 @@ CartridgeEnhanced::CartridgeEnhanced(const ByteBuffer& image, size_t size,
Logger::info(buf.str());
}
// TODO: should we mirror here too??
mySize = bsSize;
// Initialize ROM with all 0's, to fill areas that the ROM may not cover
myImage = make_unique<uInt8[]>(mySize);
std::fill_n(myImage.get(), mySize, 0);
// Directly copy the ROM image into the buffer
// Only copy up to the amount of data the ROM provides; extra unused
// space will be filled with 0's from above
std::copy_n(image.get(), std::min(mySize, size), myImage.get());
}
else
{
// Manually 'mirror' the ROM image into the buffer
for(size_t i = 0; i < System::PAGE_SIZE; i += mySize)
std::copy_n(image.get(), mySize, myImage.get() + i);
mySize = System::PAGE_SIZE;
myBankShift = 6;
}
}
else
{
mySize = size;
if(mySize < 4_KB)
myBankShift = 11;
// Allocate array for the ROM image
myImage = make_unique<uInt8[]>(mySize);
// Copy the ROM image into my buffer
std::copy_n(image.get(), mySize, myImage.get());
}
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -