diff --git a/InstructionSets/M50740/Executor.cpp b/InstructionSets/M50740/Executor.cpp
index 3e9339bda..f216f38f0 100644
--- a/InstructionSets/M50740/Executor.cpp
+++ b/InstructionSets/M50740/Executor.cpp
@@ -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);
+}
diff --git a/InstructionSets/M50740/Executor.hpp b/InstructionSets/M50740/Executor.hpp
index a15fa73de..e1b47461b 100644
--- a/InstructionSets/M50740/Executor.hpp
+++ b/InstructionSets/M50740/Executor.hpp
@@ -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);
};
}
diff --git a/Machines/Apple/AppleIIgs/ADB.cpp b/Machines/Apple/AppleIIgs/ADB.cpp
index 0247211ba..619107b65 100644
--- a/Machines/Apple/AppleIIgs/ADB.cpp
+++ b/Machines/Apple/AppleIIgs/ADB.cpp
@@ -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;
+ }
+}
diff --git a/Machines/Apple/AppleIIgs/ADB.hpp b/Machines/Apple/AppleIIgs/ADB.hpp
index 4239bdb75..5dc5552d4 100644
--- a/Machines/Apple/AppleIIgs/ADB.hpp
+++ b/Machines/Apple/AppleIIgs/ADB.hpp
@@ -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_;
};
}
diff --git a/Machines/Apple/AppleIIgs/AppleIIgs.cpp b/Machines/Apple/AppleIIgs/AppleIIgs.cpp
index 47156da16..69d62a635 100644
--- a/Machines/Apple/AppleIIgs/AppleIIgs.cpp
+++ b/Machines/Apple/AppleIIgs/AppleIIgs.cpp
@@ -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_;