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Attempt implementation of disk sync.

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This commit is contained in:
Thomas Harte 2021-11-02 18:18:59 -07:00
parent 3ceb378b9b
commit c9bf2dda16
3 changed files with 26 additions and 11 deletions
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2
Machines/Amiga/Chipset.cpp
View File

@ -670,6 +670,7 @@ void Chipset::perform(const CPU::MC68000::Microcycle &cycle) {
ApplySetClear(paula_disk_control_, 0x7fff);
disk_controller_.set_control(paula_disk_control_);
disk_.set_control(paula_disk_control_);
// TODO: should also post to Paula.
break;
case Read(0x010): // ADKCONR
@ -679,7 +680,6 @@ void Chipset::perform(const CPU::MC68000::Microcycle &cycle) {
case Write(0x07e): // DSKSYNC
disk_controller_.set_sync_word(cycle.value16());
assert(false); // Not fully implemented.
break;
case Read(0x01a): // DSKBYTR
LOG("TODO: disk status");

10
Machines/Amiga/Chipset.hpp
View File

@ -383,7 +383,8 @@ class Chipset: private ClockingHint::Observer {
public:
using DMADevice::DMADevice;
void set_length(uint16_t value);
void set_length(uint16_t);
void set_control(uint16_t);
bool advance();
void enqueue(uint16_t value, bool matches_sync);
@ -393,9 +394,16 @@ class Chipset: private ClockingHint::Observer {
bool dma_enable_ = false;
bool write_ = false;
uint16_t last_set_length_ = 0;
bool sync_with_word_ = false;
std::array<uint16_t, 4> buffer_;
size_t buffer_read_ = 0, buffer_write_ = 0;
enum class State {
Inactive,
WaitingForSync,
Reading,
} state_ = State::Inactive;
} disk_;
class DiskController: public Storage::Disk::Controller {

17
Machines/Amiga/Disk.cpp
View File

@ -16,18 +16,22 @@ using namespace Amiga;
// MARK: - Disk DMA.
void Chipset::DiskDMA::enqueue(uint16_t value, bool matches_sync) {
if(matches_sync) {
// TODO: start buffering from the next word onwards if
// syncing is enabled.
if(matches_sync && state_ == State::WaitingForSync) {
state_ = State::Reading;
return;
}
// LOG("In: " << buffer_write_);
if(state_ == State::Reading) {
buffer_[buffer_write_ & 3] = value;
if(buffer_write_ == buffer_read_ + 4) {
++buffer_read_;
}
++buffer_write_;
}
}
void Chipset::DiskDMA::set_control(uint16_t control) {
sync_with_word_ = control & 0x400;
}
void Chipset::DiskDMA::set_length(uint16_t value) {
@ -40,6 +44,8 @@ void Chipset::DiskDMA::set_length(uint16_t value) {
if(dma_enable_) {
LOG("Disk DMA " << (write_ ? "write" : "read") << " of " << length_ << " to " << PADHEX(8) << pointer_[0]);
}
state_ = sync_with_word_ ? State::WaitingForSync : State::Reading;
}
last_set_length_ = value;
@ -57,6 +63,7 @@ bool Chipset::DiskDMA::advance() {
if(!length_) {
chipset_.posit_interrupt(InterruptFlag::DiskBlock);
state_ = State::Inactive;
}
return true;