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Merge pull request #182 from TomHarte/BetterFDC

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Continues building up the 8272
This commit is contained in:
Thomas Harte 2017-08-10 11:14:08 -04:00 committed by GitHub
commit 78138261c2
3 changed files with 52 additions and 33 deletions
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75
Components/8272/i8272.cpp
View File

@ -13,10 +13,10 @@
using namespace Intel;
namespace {
const uint8_t StatusRQM = 0x80; // Set: ready to send or receive from processor.
const uint8_t StatusDIO = 0x40; // Set: data is expected to be taken from the 8272 by the processor.
const uint8_t StatusNDM = 0x20; // Set: the execution phase of a data transfer command is ongoing and DMA mode is disabled.
const uint8_t StatusCB = 0x10; // Set: the FDC is busy.
const uint8_t StatusRequest = 0x80; // Set: ready to send or receive from processor.
const uint8_t StatusDirection = 0x40; // Set: data is expected to be taken from the 8272 by the processor.
const uint8_t StatusNonDMAExecuting = 0x20; // Set: the execution phase of a data transfer command is ongoing and DMA mode is disabled.
const uint8_t StatusBusy = 0x10; // Set: the FDC is busy.
//const uint8_t StatusD3B = 0x08; // Set: drive 3 is seeking.
//const uint8_t StatusD2B = 0x04; // Set: drive 2 is seeking.
//const uint8_t StatusD1B = 0x02; // Set: drive 1 is seeking.
@ -25,7 +25,7 @@ const uint8_t StatusCB = 0x10; // Set: the FDC is busy.
i8272::i8272(Cycles clock_rate, int clock_rate_multiplier, int revolutions_per_minute) :
Storage::Disk::MFMController(clock_rate, clock_rate_multiplier, revolutions_per_minute),
main_status_(StatusRQM),
main_status_(0),
interesting_event_mask_((int)Event8272::CommandByte),
resume_point_(0),
delay_time_(0),
@ -76,7 +76,7 @@ void i8272::set_register(int address, uint8_t value) {
if(!address) return;
// if not ready for commands, do nothing
if(!(main_status_ & StatusRQM)) return;
if(!(main_status_ & StatusRequest)) return;
// accumulate latest byte in the command byte sequence
command_.push_back(value);
@ -135,7 +135,7 @@ void i8272::set_disk(std::shared_ptr<Storage::Disk::Disk> disk, int drive) {
set_data_mode(Scanning);
#define SET_DRIVE_HEAD_MFM() \
if(!dma_mode_) main_status_ |= StatusNDM; \
if(!dma_mode_) main_status_ |= StatusNonDMAExecuting; \
set_drive(drives_[command_[1]&3].drive); \
set_is_double_density(command_[0] & 0x40); \
invalidate_track();
@ -150,94 +150,94 @@ void i8272::posit_event(int event_type) {
// into wait_for_complete_command_sequence.
wait_for_command:
set_data_mode(Storage::Disk::MFMController::DataMode::Scanning);
main_status_ &= ~(StatusCB | StatusNDM);
main_status_ &= ~(StatusBusy | StatusNonDMAExecuting);
command_.clear();
// Sets the data request bit, and waits for a byte. Then sets the busy bit. Continues accepting bytes
// until it has a quantity that make up an entire command, then resets the data request bit and
// branches to that command.
wait_for_complete_command_sequence:
main_status_ |= StatusRQM;
main_status_ |= StatusRequest;
WAIT_FOR_EVENT(Event8272::CommandByte)
main_status_ |= StatusCB;
main_status_ |= StatusBusy;
switch(command_[0] & 0x1f) {
case 0x06: // read data
if(command_.size() < 9) goto wait_for_complete_command_sequence;
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto read_data;
case 0x0b: // read deleted data
if(command_.size() < 9) goto wait_for_complete_command_sequence;
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto read_deleted_data;
case 0x05: // write data
if(command_.size() < 9) goto wait_for_complete_command_sequence;
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto write_data;
case 0x09: // write deleted data
if(command_.size() < 9) goto wait_for_complete_command_sequence;
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto write_deleted_data;
case 0x02: // read track
if(command_.size() < 9) goto wait_for_complete_command_sequence;
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto read_track;
case 0x0a: // read ID
if(command_.size() < 2) goto wait_for_complete_command_sequence;
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto read_id;
case 0x0d: // format track
if(command_.size() < 6) goto wait_for_complete_command_sequence;
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto format_track;
case 0x11: // scan low
if(command_.size() < 9) goto wait_for_complete_command_sequence;
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto scan_low;
case 0x19: // scan low or equal
if(command_.size() < 9) goto wait_for_complete_command_sequence;
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto scan_low_or_equal;
case 0x1d: // scan high or equal
if(command_.size() < 9) goto wait_for_complete_command_sequence;
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto scan_high_or_equal;
case 0x07: // recalibrate
if(command_.size() < 2) goto wait_for_complete_command_sequence;
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto recalibrate;
case 0x08: // sense interrupt status
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto sense_interrupt_status;
case 0x03: // specify
if(command_.size() < 3) goto wait_for_complete_command_sequence;
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto specify;
case 0x04: // sense drive status
if(command_.size() < 2) goto wait_for_complete_command_sequence;
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto sense_drive_status;
case 0x0f: // seek
if(command_.size() < 3) goto wait_for_complete_command_sequence;
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto seek;
default: // invalid
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
goto invalid;
}
@ -277,9 +277,9 @@ void i8272::posit_event(int event_type) {
WAIT_FOR_EVENT(Event::Token);
result_stack_.push_back(get_latest_token().byte_value);
distance_into_section_++;
main_status_ |= StatusRQM | StatusDIO;
main_status_ |= StatusRequest | StatusDirection;
WAIT_FOR_EVENT(Event8272::ResultEmpty);
main_status_ &= ~StatusRQM;
main_status_ &= ~StatusRequest;
if(distance_into_section_ < (128 << size_)) goto get_byte;
// read CRC, without transferring it
@ -416,8 +416,17 @@ void i8272::posit_event(int event_type) {
goto wait_for_command;
sense_drive_status:
printf("Sense drive status unimplemented!!\n");
goto wait_for_command;
{
int drive = command_[1] & 3;
result_stack_.push_back(
(command_[1] & 7) | // drive and head number
0x08 | // single sided
(drives_[drive].drive->get_is_track_zero() ? 0x10 : 0x00) |
(drives_[drive].drive->has_disk() ? 0x20 : 0x00) | // ready, approximately (TODO)
0x40 // write protected
);
}
goto post_result;
// Performs any invalid command.
invalid:
@ -442,15 +451,15 @@ void i8272::posit_event(int event_type) {
// last thing in it will be returned first.
post_result:
// Set ready to send data to the processor, no longer in non-DMA execution phase.
main_status_ |= StatusRQM | StatusDIO;
main_status_ &= ~StatusNDM;
main_status_ |= StatusRequest | StatusDirection;
main_status_ &= ~StatusNonDMAExecuting;
// The actual stuff of unwinding result_stack_ is handled by ::get_register; wait
// until the processor has read all result bytes.
WAIT_FOR_EVENT(Event8272::ResultEmpty);
// Reset data direction and end the command.
main_status_ &= ~StatusDIO;
main_status_ &= ~StatusDirection;
goto wait_for_command;
END_SECTION()

5
Storage/Disk/Drive.cpp
View File

@ -46,6 +46,11 @@ bool Drive::get_is_read_only() {
return false;
}
bool Drive::get_is_ready() {
// TODO: a real test for this.
return disk_ != nullptr;
}
std::shared_ptr<Track> Drive::get_track() {
if(disk_) return disk_->get_track_at_position(head_, (unsigned int)head_position_);
if(track_) return track_;

5
Storage/Disk/Drive.hpp
View File

@ -65,6 +65,11 @@ class Drive {
*/
void set_track(const std::shared_ptr<Track> &track);
/*!
@returns @c true if the drive is ready; @c false otherwise.
*/
bool get_is_ready();
private:
std::shared_ptr<Track> track_;
std::shared_ptr<Disk> disk_;