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Attempts properly to track ADB bus activity.

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Output is not yet a valid ADB stream. Work to do.
This commit is contained in:
Thomas Harte 2021-01-25 17:43:22 -05:00
parent 8789ffda15
commit c8beb59172
5 changed files with 62 additions and 8 deletions
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17
InstructionSets/M50740/Executor.cpp
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@ -42,7 +42,8 @@ void Executor::set_rom(const std::vector<uint8_t> &rom) {
}
void Executor::run_for(Cycles cycles) {
// The incoming clock is divided by four.
// The incoming clock is divided by four; the local cycles_ count
// ensures that fractional parts are kept track of.
cycles_ += cycles;
CachingExecutor::run_for(cycles_.divide(Cycles(4)).as<int>());
}
@ -54,8 +55,13 @@ void Executor::reset() {
uint8_t Executor::read(uint16_t address) {
address &= 0x1fff;
if(address < 0x60) {
return memory_[address];
}
port_handler_.run_ports_for(cycles_since_port_handler_.flush<Cycles>());
switch(address) {
default: return memory_[address];
default: return 0xff;
// TODO: external IO ports.
@ -89,6 +95,8 @@ void Executor::write(uint16_t address, uint8_t value) {
return;
}
port_handler_.run_ports_for(cycles_since_port_handler_.flush<Cycles>());
// TODO: all external IO ports.
switch(address) {
default: break;
@ -706,3 +714,8 @@ template <Operation operation> void Executor::perform(uint8_t *operand [[maybe_u
}
#undef set_nz
}
inline void Executor::subtract_duration(int duration) {
cycles_since_port_handler_ += Cycles(duration);
CachingExecutor::subtract_duration(duration);
}

5
InstructionSets/M50740/Executor.hpp
View File

@ -25,6 +25,7 @@ class Executor;
using CachingExecutor = CachingExecutor<Executor, 0x1fff, 255, Instruction, false>;
struct PortHandler {
virtual void run_ports_for(Cycles) = 0;
virtual void set_port_output(int port, uint8_t value) = 0;
virtual uint8_t get_port_input(int port) = 0;
};
@ -143,8 +144,12 @@ class Executor: public CachingExecutor {
inline uint8_t flags();
template<bool is_brk> inline void perform_interrupt();
// MARK: - Execution time
Cycles cycles_;
Cycles cycles_since_port_handler_;
PortHandler &port_handler_;
inline void subtract_duration(int duration);
};
}

40
Machines/Apple/AppleIIgs/ADB.cpp
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@ -240,13 +240,36 @@ void GLU::set_port_output(int port, uint8_t value) {
// printf("IIe keyboard reset line: %d\n", (value >> 6)&1);
// printf("IIgs reset line: %d\n", (value >> 5)&1);
// printf("GLU strobe: %d\n", (value >> 4)&1);
printf("Select GLU register: %d [%02x]\n", value & 0xf, value);
// printf("Select GLU register: %d [%02x]\n", value & 0xf, value);
register_address_ = value & 0xf;
break;
case 3:
case 3: {
// printf("IIe KWS: %d\n", (value >> 6)&3);
printf("ADB data line output: %d\n", (value >> 3)&1);
break;
// printf("ADB data line output: %d\n", (value >> 3)&1);
const bool new_adb_level = value & 0x08;
if(new_adb_level != adb_level_) {
if(!new_adb_level) {
// Transition to low.
constexpr float clock_rate = 894886.25;
const float seconds = float(total_period_.as<int>()) / clock_rate;
// Check for a valid bit length — 70 to 130 microseconds.
// (Plus a little).
if(seconds >= 0.000'56 && seconds <= 0.001'04) {
printf("Attention\n");
} else if(seconds >= 0.000'06 && seconds <= 0.000'14) {
printf("bit: %d\n", (low_period_.as<int>() * 2) < total_period_.as<int>());
// printf("tested: %0.2f\n", float(low_period_.as<int>()) / float(total_period_.as<int>()));
} else {
printf("Rejected %d microseconds\n", int(seconds * 1'000'000.0f));
}
total_period_ = low_period_ = Cycles(0);
}
adb_level_ = new_adb_level;
}
} break;
default: assert(false);
}
@ -261,7 +284,7 @@ uint8_t GLU::get_port_input(int port) {
// printf("IIe keyboard read\n");
return 0x06;
case 2:
printf("ADB data line input, etc\n");
// printf("ADB data line input, etc\n");
return ports_[2];
case 3:
// printf("ADB data line output, etc\n");
@ -271,3 +294,10 @@ uint8_t GLU::get_port_input(int port) {
}
return 0xff;
}
void GLU::run_ports_for(Cycles cycles) {
total_period_ += cycles;
if(!adb_level_) {
low_period_ += cycles;
}
}

5
Machines/Apple/AppleIIgs/ADB.hpp
View File

@ -62,12 +62,17 @@ class GLU: public InstructionSet::M50740::PortHandler {
InstructionSet::M50740::Executor executor_;
void run_ports_for(Cycles) override;
void set_port_output(int port, uint8_t value) override;
uint8_t get_port_input(int port) override;
uint8_t registers_[16];
uint8_t register_address_;
uint8_t ports_[4];
// TODO: this should be per peripheral. But I'm putting it here for now as an exploratory step.
bool adb_level_ = true;
Cycles low_period_, total_period_;
};
}

3
Machines/Apple/AppleIIgs/AppleIIgs.cpp
View File

@ -186,6 +186,7 @@ class ConcreteMachine:
void flush() {
video_.flush();
iwm_.flush();
adb_glu_.flush();
AudioUpdater updater(this);
audio_queue_.perform();
@ -916,7 +917,7 @@ class ConcreteMachine:
Apple::Clock::ParallelClock clock_;
JustInTimeActor<Apple::IIgs::Video::Video, 1, 2, Cycles> video_; // i.e. run video at 7Mhz.
JustInTimeActor<Apple::IIgs::ADB::GLU, 1, 4, Cycles> adb_glu_;
JustInTimeActor<Apple::IIgs::ADB::GLU, 1, 4, Cycles> adb_glu_; // i.e. 3,579,545Mhz.
Zilog::SCC::z8530 scc_;
JustInTimeActor<Apple::IWM, 1, 2, Cycles> iwm_;
Cycles cycles_since_clock_tick_;