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Makes some sort of first attempt at having the IWM read.

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This commit is contained in:
Thomas Harte
2019-06-04 22:13:00 -04:00
parent 833258f3d7
commit a413ae11cb
4 changed files with 82 additions and 8 deletions
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Components/DiskII/IWM.cpp
+43 -1
View File
@@ -59,8 +59,12 @@ uint8_t IWM::read(int address) {
return 0xff;
case ENABLE: /* Read data register. */
if(data_register_ & 0x80) {
printf("[%02x] ", data_register_);
data_register_ = 0;
}
printf("Reading data register\n");
return 0x00;
return data_register_;
case Q6: case Q6|ENABLE: {
/*
@@ -257,11 +261,49 @@ void IWM::run_for(const Cycles cycles) {
}
// Activity otherwise depends on mode and motor state.
const bool run_disk = drive_motor_on_ && drives_[active_drive_];
int integer_cycles = cycles.as_int();
switch(state_ & (Q6 | Q7 | ENABLE)) {
case ENABLE: // i.e. read mode.
while(integer_cycles--) {
if(run_disk) {
drives_[active_drive_]->run_for(Cycles(1));
}
++cycles_since_shift_;
if(cycles_since_shift_ == bit_length_ + Cycles(2)) {
propose_shift(0);
}
}
break;
default:
if(run_disk) drives_[active_drive_]->run_for(cycles);
break;
}
}
void IWM::process_event(const Storage::Disk::Track::Event &event) {
switch(event.type) {
case Storage::Disk::Track::Event::IndexHole: return;
case Storage::Disk::Track::Event::FluxTransition:
propose_shift(1);
break;
}
}
void IWM::propose_shift(uint8_t bit) {
// TODO: synchronous mode.
shift_register_ = uint8_t((shift_register_ << 1) | bit);
if(shift_register_ & 0x80) {
printf("%02x -> data\n", shift_register_);
data_register_ = shift_register_;
shift_register_ = 0;
}
cycles_since_shift_ = Cycles(0);
}
void IWM::set_drive(int slot, Storage::Disk::Drive *drive) {
drives_[slot] = drive;
drive->set_event_delegate(this);
}
Components/DiskII/IWM.hpp
+9 -1
View File
@@ -16,7 +16,8 @@
namespace Apple {
class IWM {
class IWM:
public Storage::Disk::Drive::EventDelegate {
public:
IWM(int clock_rate);
@@ -42,8 +43,12 @@ class IWM {
void set_drive(int slot, Storage::Disk::Drive *drive);
private:
// Storage::Disk::Drive::EventDelegate.
void process_event(const Storage::Disk::Track::Event &event) override;
const int clock_rate_;
uint8_t data_register_ = 0;
uint8_t mode_ = 0;
bool read_write_ready_ = true;
bool write_overran_ = false;
@@ -58,6 +63,9 @@ class IWM {
void access(int address);
uint8_t shift_register_ = 0;
void propose_shift(uint8_t bit);
Cycles cycles_since_shift_;
Cycles bit_length_;
};