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Add a compiletime 'turbo' flag for sort-of-80286 speeds.
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Thomas Harte
parent
e55a09962f
commit
3a103217d1
@ -908,7 +908,7 @@ class FlowController {
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bool halted_ = false;
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};
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template <VideoAdaptor video>
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template <VideoAdaptor video, bool turbo>
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class ConcreteMachine:
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public Machine,
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public MachineTypes::TimedMachine,
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@ -975,9 +975,15 @@ class ConcreteMachine:
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// MARK: - TimedMachine.
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void run_for(const Cycles duration) override {
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const auto pit_ticks = duration.as_integral();
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cpu_divisor_ += pit_ticks;
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int ticks = cpu_divisor_ / 3;
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cpu_divisor_ %= 3;
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int ticks;
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if constexpr (!turbo) {
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cpu_divisor_ += pit_ticks;
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ticks = cpu_divisor_ / 3;
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cpu_divisor_ %= 3;
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} else {
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ticks = pit_ticks;
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}
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while(ticks--) {
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//
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@ -989,23 +995,30 @@ class ConcreteMachine:
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//
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pit_.run_for(1);
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++speaker_.cycles_since_update;
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pit_.run_for(1);
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++speaker_.cycles_since_update;
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pit_.run_for(1);
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++speaker_.cycles_since_update;
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if constexpr (!turbo) {
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pit_.run_for(1);
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++speaker_.cycles_since_update;
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pit_.run_for(1);
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++speaker_.cycles_since_update;
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}
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//
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// Advance CRTC at a more approximate rate.
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//
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video_.run_for(Cycles(3));
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video_.run_for(turbo ? Cycles(1) : Cycles(3));
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//
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// Give the keyboard a notification of passing time; it's very approximately clocked,
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// really just including 'some' delays to avoid being instant.
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//
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keyboard_.run_for(Cycles(1));
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//
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// Perform one CPU instruction every three PIT cycles.
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// i.e. CPU instruction rate is 1/3 * ~1.19Mhz ~= 0.4 MIPS.
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//
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keyboard_.run_for(Cycles(1));
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// Query for interrupts and apply if pending.
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if(pic_.pending() && context.flags.template flag<InstructionSet::x86::Flag::Interrupt>()) {
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// Regress the IP if a REP is in-progress so as to resume it later.
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@ -1022,58 +1035,77 @@ class ConcreteMachine:
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);
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}
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// Do nothing if halted.
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// Do nothing if currently halted.
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if(context.flow_controller.halted()) {
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continue;
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}
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// Get the next thing to execute.
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if(!context.flow_controller.should_repeat()) {
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// Decode from the current IP.
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decoded_ip_ = context.registers.ip();
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const auto remainder = context.memory.next_code();
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decoded = decoder.decode(remainder.first, remainder.second);
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// If that didn't yield a whole instruction then the end of memory must have been hit;
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// continue from the beginning.
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if(decoded.first <= 0) {
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const auto all = context.memory.all();
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decoded = decoder.decode(all.first, all.second);
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}
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context.registers.ip() += decoded.first;
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if constexpr (turbo) {
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// There's no divider applied, so this makes for 2*PI = around 2.4 MIPS.
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// That's broadly 80286 speed, if MIPS were a valid measure.
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perform_instruction();
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perform_instruction();
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} else {
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context.flow_controller.begin_instruction();
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// With the clock divider above, this makes for a net of PIT/3 = around 0.4 MIPS.
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// i.e. a shade more than 8086 speed, if MIPS were meaningful.
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perform_instruction();
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}
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/* if(decoded_ip_ >= 0x7c00 && decoded_ip_ < 0x7c00 + 1024) {
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const auto next = to_string(decoded, InstructionSet::x86::Model::i8086);
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// if(next != previous) {
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std::cout << std::hex << decoded_ip_ << " " << next;
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if(decoded.second.operation() == InstructionSet::x86::Operation::INT) {
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std::cout << " dl:" << std::hex << +context.registers.dl() << "; ";
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std::cout << "ah:" << std::hex << +context.registers.ah() << "; ";
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std::cout << "ch:" << std::hex << +context.registers.ch() << "; ";
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std::cout << "cl:" << std::hex << +context.registers.cl() << "; ";
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std::cout << "dh:" << std::hex << +context.registers.dh() << "; ";
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std::cout << "es:" << std::hex << +context.registers.es() << "; ";
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std::cout << "bx:" << std::hex << +context.registers.bx();
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}
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std::cout << std::endl;
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// previous = next;
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// }
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}*/
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// Execute it.
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InstructionSet::x86::perform(
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decoded.second,
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context
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);
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// Other inevitably broad and fuzzy and inconsistent MIPS counts for my own potential future play:
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//
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// 80386 @ 20Mhz: 4–5 MIPS.
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// 80486 @ 66Mhz: 25 MIPS.
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// Pentium @ 100Mhz: 188 MIPS.
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}
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}
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void perform_instruction() {
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// Get the next thing to execute.
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if(!context.flow_controller.should_repeat()) {
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// Decode from the current IP.
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decoded_ip_ = context.registers.ip();
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const auto remainder = context.memory.next_code();
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decoded = decoder.decode(remainder.first, remainder.second);
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// If that didn't yield a whole instruction then the end of memory must have been hit;
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// continue from the beginning.
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if(decoded.first <= 0) {
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const auto all = context.memory.all();
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decoded = decoder.decode(all.first, all.second);
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}
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context.registers.ip() += decoded.first;
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} else {
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context.flow_controller.begin_instruction();
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}
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/* if(decoded_ip_ >= 0x7c00 && decoded_ip_ < 0x7c00 + 1024) {
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const auto next = to_string(decoded, InstructionSet::x86::Model::i8086);
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// if(next != previous) {
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std::cout << std::hex << decoded_ip_ << " " << next;
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if(decoded.second.operation() == InstructionSet::x86::Operation::INT) {
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std::cout << " dl:" << std::hex << +context.registers.dl() << "; ";
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std::cout << "ah:" << std::hex << +context.registers.ah() << "; ";
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std::cout << "ch:" << std::hex << +context.registers.ch() << "; ";
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std::cout << "cl:" << std::hex << +context.registers.cl() << "; ";
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std::cout << "dh:" << std::hex << +context.registers.dh() << "; ";
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std::cout << "es:" << std::hex << +context.registers.es() << "; ";
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std::cout << "bx:" << std::hex << +context.registers.bx();
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}
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std::cout << std::endl;
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// previous = next;
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// }
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}*/
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// Execute it.
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InstructionSet::x86::perform(
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decoded.second,
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context
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);
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}
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// MARK: - ScanProducer.
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void set_scan_target(Outputs::Display::ScanTarget *scan_target) override {
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video_.set_scan_target(scan_target);
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@ -1205,8 +1237,8 @@ Machine *Machine::PCCompatible(const Analyser::Static::Target *target, const ROM
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const Target *const pc_target = dynamic_cast<const Target *>(target);
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switch(pc_target->adaptor) {
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case VideoAdaptor::MDA: return new PCCompatible::ConcreteMachine<VideoAdaptor::MDA>(*pc_target, rom_fetcher);
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case VideoAdaptor::CGA: return new PCCompatible::ConcreteMachine<VideoAdaptor::CGA>(*pc_target, rom_fetcher);
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case VideoAdaptor::MDA: return new PCCompatible::ConcreteMachine<VideoAdaptor::MDA, false>(*pc_target, rom_fetcher);
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case VideoAdaptor::CGA: return new PCCompatible::ConcreteMachine<VideoAdaptor::CGA, false>(*pc_target, rom_fetcher);
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default: return nullptr;
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}
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}
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