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Implemented the MegaBoy paging scheme.

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This commit is contained in:
Thomas Harte 2017-03-14 17:40:01 -04:00
parent 4a528b9ecb
commit 3b29276228
2 changed files with 19 additions and 5 deletions
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23
Machines/Atari2600/Atari2600.cpp
View File

@ -94,6 +94,20 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
rom_pages_[slot] = &rom_[target * 1024];
}
break;
case StaticAnalyser::Atari2600PagingModel::MegaBoy:
if(masked_address == 0x1fec && isReadOperation(operation))
{
*value = mega_boy_page_;
}
if(masked_address == 0x1ff0)
{
mega_boy_page_ = (mega_boy_page_ + 1) & 15;
rom_pages_[0] = &rom_[mega_boy_page_ * 4096];
rom_pages_[1] = rom_pages_[0] + 1024;
rom_pages_[2] = rom_pages_[0] + 2048;
rom_pages_[3] = rom_pages_[0] + 3072;
}
break;
}
#undef AtariPager
@ -279,9 +293,7 @@ void Machine::configure_as_target(const StaticAnalyser::Target &target)
Storage::Cartridge::Cartridge::Segment segment = target.cartridges.front()->get_segments().front();
size_t length = segment.data.size();
rom_size_ = 1024;
while(rom_size_ < length && rom_size_ < 32768) rom_size_ <<= 1;
rom_size_ = length;
delete[] rom_;
rom_ = new uint8_t[rom_size_];
@ -315,20 +327,21 @@ void Machine::configure_as_target(const StaticAnalyser::Target &target)
ram_read_start_ = 0x1080;
}
break;
case StaticAnalyser::Atari2600PagingModel::CBSRamPlus:
ram_.resize(256);
has_ram_ = true;
ram_write_start_ = 0x1000;
ram_read_start_ = 0x1100;
break;
case StaticAnalyser::Atari2600PagingModel::CommaVid:
ram_.resize(1024);
has_ram_ = true;
ram_write_start_ = 0x1400;
ram_read_start_ = 0x1000;
break;
case StaticAnalyser::Atari2600PagingModel::MegaBoy:
mega_boy_page_ = 15;
break;
}
paging_model_ = target.atari.paging_model;

1
Machines/Atari2600/Atari2600.hpp
View File

@ -59,6 +59,7 @@ class Machine:
// ROM information
uint8_t *rom_, *rom_pages_[4];
size_t rom_size_;
uint8_t mega_boy_page_;
StaticAnalyser::Atari2600PagingModel paging_model_;
// cartridge RAM expansion store