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Merge pull request #105 from TomHarte/ParkerBros

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Introduces detection and emulation of the Parker Bros paging scheme
This commit is contained in:
Thomas Harte 2017-03-11 13:05:17 -05:00 committed by GitHub
commit 3f36eeb071
3 changed files with 92 additions and 37 deletions
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58
Machines/Atari2600/Atari2600.cpp
View File

@ -66,30 +66,42 @@ unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uin
cycles_since_6532_update_ += (cycles_run_for / 3);
if(operation != CPU6502::BusOperation::Ready) {
uint16_t masked_address = address & 0x1fff;
// check for a paging access
if(rom_size_ > 4096 && ((address & 0x1f00) == 0x1f00)) {
uint8_t *base_ptr = rom_pages_[0];
uint8_t first_paging_register = (uint8_t)(0xf8 - (rom_size_ >> 14)*2);
// check for potential paging
switch(paging_model_) {
default:
// check for an Atari paging access
if(rom_size_ > 4096 && ((address & 0x1f00) == 0x1f00)) {
uint8_t *base_ptr = rom_pages_[0];
uint8_t first_paging_register = (uint8_t)(0xf8 - (rom_size_ >> 14)*2);
const uint8_t paging_register = address&0xff;
if(paging_register >= first_paging_register) {
const uint16_t selected_page = paging_register - first_paging_register;
if(selected_page * 4096 < rom_size_) {
base_ptr = &rom_[selected_page * 4096];
const uint8_t paging_register = address&0xff;
if(paging_register >= first_paging_register) {
const uint16_t selected_page = paging_register - first_paging_register;
if(selected_page * 4096 < rom_size_) {
base_ptr = &rom_[selected_page * 4096];
}
}
if(base_ptr != rom_pages_[0]) {
rom_pages_[0] = base_ptr;
rom_pages_[1] = base_ptr + 1024;
rom_pages_[2] = base_ptr + 2048;
rom_pages_[3] = base_ptr + 3072;
}
}
}
if(base_ptr != rom_pages_[0]) {
rom_pages_[0] = base_ptr;
rom_pages_[1] = base_ptr + 1024;
rom_pages_[2] = base_ptr + 2048;
rom_pages_[3] = base_ptr + 3072;
}
break;
case StaticAnalyser::Atari2600PagingModel::ParkerBros:
if(masked_address >= 0x1fe0 && masked_address < 0x1ff8) {
int slot = (masked_address >> 3) & 3;
int target = masked_address & 7;
rom_pages_[slot] = &rom_[target * 1024];
}
break;
}
// check for a ROM read
uint16_t masked_address = address & 0x1fff;
if(address&0x1000)
{
// check for a RAM access
@ -278,13 +290,13 @@ void Machine::configure_as_target(const StaticAnalyser::Target &target)
// On a real paged cartridge, any page may initially be visible. Various homebrew authors appear to have
// decided the last page will always be initially visible. So do that.
size_t romMask = rom_size_ - 1;
size_t rom_mask = rom_size_ - 1;
uint8_t *rom_base = rom_;
if(rom_size_ > 4096) rom_base = &rom_[rom_size_ - 4096];
rom_pages_[0] = rom_base;
rom_pages_[1] = &rom_base[1024 & romMask];
rom_pages_[2] = &rom_base[2048 & romMask];
rom_pages_[3] = &rom_base[3072 & romMask];
rom_pages_[1] = &rom_base[1024 & rom_mask];
rom_pages_[2] = &rom_base[2048 & rom_mask];
rom_pages_[3] = &rom_base[3072 & rom_mask];
switch(target.atari.paging_model)
{
@ -305,6 +317,8 @@ void Machine::configure_as_target(const StaticAnalyser::Target &target)
ram_read_start_ = 0x1000;
break;
}
paging_model_ = target.atari.paging_model;
}
#pragma mark - Audio and Video

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_;
StaticAnalyser::Atari2600PagingModel paging_model_;
// cartridge RAM expansion store
std::vector<uint8_t> ram_;

70
StaticAnalyser/Atari/StaticAnalyser.cpp
View File

@ -90,6 +90,28 @@ static void DeterminePagingFor2kCartridge(StaticAnalyser::Target &target, const
target.atari.paging_model = StaticAnalyser::Atari2600PagingModel::CommaVid;
}
static void DeterminePagingFor8kCartridge(StaticAnalyser::Target &target, const Storage::Cartridge::Cartridge::Segment &segment, const std::vector<StaticAnalyser::MOS6502::Disassembly> &disassemblies)
{
std::set<uint16_t> internal_accesses;
for(const StaticAnalyser::MOS6502::Disassembly &disassembly : disassemblies)
{
internal_accesses.insert(disassembly.internal_stores.begin(), disassembly.internal_stores.end());
internal_accesses.insert(disassembly.internal_modifies.begin(), disassembly.internal_modifies.end());
internal_accesses.insert(disassembly.internal_loads.begin(), disassembly.internal_loads.end());
}
bool looks_like_atari = false;
bool looks_like_parker_bros = false;
for(uint16_t address : internal_accesses)
{
looks_like_atari |= ((address & 0x1fff) >= 0x1ff8) && ((address & 0x1fff) < 0x1ffa);
looks_like_parker_bros |= ((address & 0x1fff) >= 0x1fe0) && ((address & 0x1fff) < 0x1fe8);
}
if(looks_like_parker_bros) target.atari.paging_model = StaticAnalyser::Atari2600PagingModel::ParkerBros;
if(looks_like_atari) target.atari.paging_model = StaticAnalyser::Atari2600PagingModel::Atari8k;
}
static void DeterminePagingForCartridge(StaticAnalyser::Target &target, const Storage::Cartridge::Cartridge::Segment &segment)
{
if(segment.data.size() == 2048)
@ -100,8 +122,8 @@ static void DeterminePagingForCartridge(StaticAnalyser::Target &target, const St
uint16_t entry_address, break_address;
entry_address = (uint16_t)(segment.data[0xffc] | (segment.data[0xffd] << 8));
break_address = (uint16_t)(segment.data[0xffe] | (segment.data[0xfff] << 8));
entry_address = (uint16_t)(segment.data[segment.data.size() - 4] | (segment.data[segment.data.size() - 3] << 8));
break_address = (uint16_t)(segment.data[segment.data.size() - 2] | (segment.data[segment.data.size() - 1] << 8));
std::function<size_t(uint16_t address)> address_mapper = [](uint16_t address) {
if(!(address & 0x1000)) return (size_t)-1;
@ -112,25 +134,43 @@ static void DeterminePagingForCartridge(StaticAnalyser::Target &target, const St
std::set<uint16_t> internal_stores;
for(std::vector<uint8_t>::difference_type base = 0; base < segment.data.size(); base += 4096)
{
std::vector<uint8_t> sub_data(segment.data.begin() + base, segment.data.begin() + base + 2048);
std::vector<uint8_t> sub_data(segment.data.begin() + base, segment.data.begin() + base + 4096);
disassemblies.push_back(StaticAnalyser::MOS6502::Disassemble(sub_data, address_mapper, {entry_address, break_address}));
internal_stores.insert(disassemblies.back().internal_stores.begin(), disassemblies.back().internal_stores.end());
}
// check for any sort of on-cartridge RAM; that might imply a Super Chip or else immediately tip the
// hat that this is a CBS RAM+ cartridge
if(internal_stores.size() > 4)
if(segment.data.size() == 8192)
{
bool writes_above_128 = false;
for(uint16_t address : internal_stores)
{
writes_above_128 |= ((address & 0x1fff) > 0x10ff) && ((address & 0x1fff) < 0x1200);
}
if(writes_above_128)
target.atari.paging_model = StaticAnalyser::Atari2600PagingModel::CBSRamPlus;
else
target.atari.uses_superchip = true;
DeterminePagingFor8kCartridge(target, segment, disassemblies);
}
// check for any sort of on-cartridge RAM; that might imply a Super Chip or else immediately tip the
// hat that this is a CBS RAM+ cartridge. Atari ROM images always have the same value stored over RAM
// regions.
bool has_superchip = true;
bool is_ram_plus = true;
for(size_t address = 0; address < 256; address++)
{
if(segment.data[address] != segment.data[0])
{
if(address < 128) has_superchip = false;
is_ram_plus = false;
}
}
target.atari.uses_superchip = has_superchip;
if(is_ram_plus) target.atari.paging_model = StaticAnalyser::Atari2600PagingModel::CBSRamPlus;
// if(internal_stores.size() > 4)
// {
// bool writes_above_128 = false;
// for(uint16_t address : internal_stores)
// {
// writes_above_128 |= ((address & 0x1fff) > 0x10ff) && ((address & 0x1fff) < 0x1200);
// }
// if(writes_above_128)
// target.atari.paging_model = StaticAnalyser::Atari2600PagingModel::CBSRamPlus;
// else
// target.atari.uses_superchip = true;
// }
}
void StaticAnalyser::Atari::AddTargets(