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Ensures intended 65816 exception behaviour.

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i.e. the relevant micro-op sequence exists, and its operation isn't lost. Also sets the 65816 by default to jump straight into power-on, not to execute an instruction first. That shouldn't make a functional difference, but it makes debugging easier because it makes startup fully deterministic.
This commit is contained in:
Thomas Harte 2020-10-18 14:43:47 -04:00
parent 69509f6502
commit 99eba2f8ba
4 changed files with 68 additions and 57 deletions
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5
OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme
View File

@ -48,11 +48,6 @@
BlueprintName = "Clock SignalTests"
ReferencedContainer = "container:Clock Signal.xcodeproj">
</BuildableReference>
<SkippedTests>
<Test
Identifier = "ZexallTests">
</Test>
</SkippedTests>
</TestableReference>
<TestableReference
skipped = "YES">

7
Processors/65816/Implementation/65816Implementation.hpp
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@ -50,8 +50,10 @@ template <typename BusHandler, bool uses_ready_line> void Processor<BusHandler,
// The exception program will determine the appropriate way to respond
// based on the pending exception if one exists; otherwise just do a
// standard fetch-decode-execute.
const auto offset = instructions[selected_exceptions_ ? size_t(OperationSlot::Exception) : size_t(OperationSlot::FetchDecodeExecute)].program_offsets[0];
next_op_ = &micro_ops_[offset];
const size_t slot = size_t(selected_exceptions_ ? OperationSlot::Exception : OperationSlot::FetchDecodeExecute);
active_instruction_ = &instructions[slot];
next_op_ = &micro_ops_[active_instruction_->program_offsets[0]];
instruction_buffer_.clear();
data_buffer_.clear();
last_operation_pc_ = registers_.pc;
@ -954,6 +956,7 @@ void ProcessorBase::set_power_on(bool active) {
pending_exceptions_ |= PowerOn;
} else {
pending_exceptions_ &= ~PowerOn;
selected_exceptions_ &= ~PowerOn;
}
}

107
Processors/65816/Implementation/65816Storage.cpp
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@ -43,7 +43,8 @@ struct CPU::WDC65816::ProcessorStorageConstructor {
typedef void (* Generator)(AccessType, bool, const std::function<void(MicroOp)>&);
using GeneratorKey = std::tuple<AccessType, Generator>;
std::map<GeneratorKey, std::pair<size_t, size_t>> installed_patterns;
using PatternTable = std::map<GeneratorKey, std::pair<size_t, size_t>>;
PatternTable installed_patterns;
int opcode = 0;
enum class AccessMode {
@ -51,55 +52,15 @@ struct CPU::WDC65816::ProcessorStorageConstructor {
Always8Bit,
Always16Bit
};
void install(Generator generator, Operation operation, AccessMode access_mode = AccessMode::Mixed) {
// Determine the access type implied by this operation.
const AccessType access_type = access_type_for_operation(operation);
// Check whether this access type + addressing mode generator has already been generated.
const auto key = std::make_pair(access_type, generator);
const auto map_entry = installed_patterns.find(key);
size_t micro_op_location_8, micro_op_location_16;
// If it wasn't found, generate it now in both 8- and 16-bit variants.
// Otherwise, get the location of the existing entries.
if(map_entry == installed_patterns.end()) {
// Generate 8-bit steps.
micro_op_location_8 = storage_.micro_ops_.size();
(*generator)(access_type, true, [this] (MicroOp op) {
this->storage_.micro_ops_.push_back(op);
});
storage_.micro_ops_.push_back(OperationMoveToNextProgram);
// Generate 16-bit steps.
micro_op_location_16 = storage_.micro_ops_.size();
(*generator)(access_type, false, [this] (MicroOp op) {
this->storage_.micro_ops_.push_back(op);
});
storage_.micro_ops_.push_back(OperationMoveToNextProgram);
// Minor optimisation: elide the steps if 8- and 16-bit steps are equal.
bool are_equal = true;
size_t c = 0;
while(true) {
if(storage_.micro_ops_[micro_op_location_8 + c] != storage_.micro_ops_[micro_op_location_16 + c]) {
are_equal = false;
break;
}
if(storage_.micro_ops_[micro_op_location_8 + c] == OperationMoveToNextProgram) break;
++c;
}
if(are_equal) {
storage_.micro_ops_.resize(micro_op_location_16);
micro_op_location_16 = micro_op_location_8;
}
// Insert into the map.
installed_patterns[key] = std::make_pair(micro_op_location_8, micro_op_location_16);
} else {
micro_op_location_8 = map_entry->second.first;
micro_op_location_16 = map_entry->second.second;
}
// Install the bus pattern.
const auto map_entry = install(generator, access_type);
const size_t micro_op_location_8 = map_entry->second.first;
const size_t micro_op_location_16 = map_entry->second.second;
// Fill in the proper table entries and increment the opcode pointer.
storage_.instructions[opcode].program_offsets[0] = (access_mode == AccessMode::Always8Bit) ? uint16_t(micro_op_location_8) : uint16_t(micro_op_location_16);
@ -110,8 +71,7 @@ struct CPU::WDC65816::ProcessorStorageConstructor {
}
void set_exception_generator(Generator generator) {
const auto key = std::make_pair(AccessType::Read, generator);
const auto map_entry = installed_patterns.find(key);
const auto map_entry = install(generator);
storage_.instructions[size_t(ProcessorStorage::OperationSlot::Exception)].program_offsets[0] =
storage_.instructions[size_t(ProcessorStorage::OperationSlot::Exception)].program_offsets[1] = uint16_t(map_entry->second.first);
storage_.instructions[size_t(ProcessorStorage::OperationSlot::Exception)].operation = JMPind;
@ -124,6 +84,57 @@ struct CPU::WDC65816::ProcessorStorageConstructor {
storage_.micro_ops_.push_back(OperationDecode);
}
private:
PatternTable::iterator install(Generator generator, AccessType access_type = AccessType::Read) {
// Check whether this access type + addressing mode generator has already been generated.
const auto key = std::make_pair(access_type, generator);
const auto map_entry = installed_patterns.find(key);
// If it wasn't found, generate it now in both 8- and 16-bit variants.
// Otherwise, get the location of the existing entries.
if(map_entry != installed_patterns.end()) {
return map_entry;
}
// Generate 8-bit steps.
const size_t micro_op_location_8 = storage_.micro_ops_.size();
(*generator)(access_type, true, [this] (MicroOp op) {
this->storage_.micro_ops_.push_back(op);
});
storage_.micro_ops_.push_back(OperationMoveToNextProgram);
// Generate 16-bit steps.
size_t micro_op_location_16 = storage_.micro_ops_.size();
(*generator)(access_type, false, [this] (MicroOp op) {
this->storage_.micro_ops_.push_back(op);
});
storage_.micro_ops_.push_back(OperationMoveToNextProgram);
// Minor optimisation: elide the steps if 8- and 16-bit steps are equal.
bool are_equal = true;
size_t c = 0;
while(true) {
if(storage_.micro_ops_[micro_op_location_8 + c] != storage_.micro_ops_[micro_op_location_16 + c]) {
are_equal = false;
break;
}
if(storage_.micro_ops_[micro_op_location_8 + c] == OperationMoveToNextProgram) break;
++c;
}
if(are_equal) {
storage_.micro_ops_.resize(micro_op_location_16);
micro_op_location_16 = micro_op_location_8;
}
// Insert into the map.
auto [iterator, _] = installed_patterns.insert(std::make_pair(key, std::make_pair(micro_op_location_8, micro_op_location_16)));
return iterator;
}
public:
/*
Code below is structured to ease translation from Table 5-7 of the 2018
edition of the WDC 65816 datasheet.

6
Processors/65816/Implementation/65816Storage.hpp
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@ -292,8 +292,10 @@ struct ProcessorStorage {
static constexpr int IRQ = Flag::Interrupt; // This makes masking a lot easier later on; this is 1 << 2.
static constexpr int NMI = 1 << 3;
static constexpr int Abort = 1 << 4;
int pending_exceptions_ = PowerOn; // By default.
int selected_exceptions_ = 0;
static constexpr int default_exceptions = PowerOn;
int pending_exceptions_ = default_exceptions;
int selected_exceptions_ = default_exceptions;
bool ready_line_ = false;
bool memory_lock_ = false;