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c1bae49a92
Logic being: name these things for the bus action they model, not the effect they have.
895 lines
28 KiB
C++
895 lines
28 KiB
C++
//
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// i8272.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 05/08/2017.
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// Copyright 2017 Thomas Harte. All rights reserved.
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//
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#include "i8272.hpp"
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#include "../../Outputs/Log.hpp"
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using namespace Intel::i8272;
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#define SetDataRequest() (main_status_ |= 0x80)
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#define ResetDataRequest() (main_status_ &= ~0x80)
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#define DataRequest() (main_status_ & 0x80)
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#define SetDataDirectionToProcessor() (main_status_ |= 0x40)
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#define SetDataDirectionFromProcessor() (main_status_ &= ~0x40)
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#define DataDirectionToProcessor() (main_status_ & 0x40)
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#define SetNonDMAExecution() (main_status_ |= 0x20)
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#define ResetNonDMAExecution() (main_status_ &= ~0x20)
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#define SetBusy() (main_status_ |= 0x10)
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#define ResetBusy() (main_status_ &= ~0x10)
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#define Busy() (main_status_ & 0x10)
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#define SetAbnormalTermination() (status_[0] |= 0x40)
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#define SetInvalidCommand() (status_[0] |= 0x80)
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#define SetReadyChanged() (status_[0] |= 0xc0)
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#define SetSeekEnd() (status_[0] |= 0x20)
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#define SetEquipmentCheck() (status_[0] |= 0x10)
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#define SetNotReady() (status_[0] |= 0x08)
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#define SetSide2() (status_[0] |= 0x04)
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#define SetEndOfCylinder() (status_[1] |= 0x80)
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#define SetDataError() (status_[1] |= 0x20)
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#define SetOverrun() (status_[1] |= 0x10)
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#define SetNoData() (status_[1] |= 0x04)
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#define SetNotWriteable() (status_[1] |= 0x02)
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#define SetMissingAddressMark() (status_[1] |= 0x01)
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#define SetControlMark() (status_[2] |= 0x40)
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#define ClearControlMark() (status_[2] &= ~0x40)
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#define ControlMark() (status_[2] & 0x40)
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#define SetDataFieldDataError() (status_[2] |= 0x20)
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#define SetWrongCyinder() (status_[2] |= 0x10)
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#define SetScanEqualHit() (status_[2] |= 0x08)
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#define SetScanNotSatisfied() (status_[2] |= 0x04)
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#define SetBadCylinder() (status_[2] |= 0x02)
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#define SetMissingDataAddressMark() (status_[2] |= 0x01)
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namespace {
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const uint8_t CommandReadData = 0x06;
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const uint8_t CommandReadDeletedData = 0x0c;
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const uint8_t CommandWriteData = 0x05;
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const uint8_t CommandWriteDeletedData = 0x09;
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const uint8_t CommandReadTrack = 0x02;
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const uint8_t CommandReadID = 0x0a;
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const uint8_t CommandFormatTrack = 0x0d;
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const uint8_t CommandScanLow = 0x11;
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const uint8_t CommandScanLowOrEqual = 0x19;
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const uint8_t CommandScanHighOrEqual = 0x1d;
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const uint8_t CommandRecalibrate = 0x07;
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const uint8_t CommandSeek = 0x0f;
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const uint8_t CommandSenseInterruptStatus = 0x08;
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const uint8_t CommandSpecify = 0x03;
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const uint8_t CommandSenseDriveStatus = 0x04;
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}
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i8272::i8272(BusHandler &bus_handler, Cycles clock_rate) :
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Storage::Disk::MFMController(clock_rate),
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bus_handler_(bus_handler) {
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posit_event(static_cast<int>(Event8272::CommandByte));
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}
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ClockingHint::Preference i8272::preferred_clocking() {
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const auto mfm_controller_preferred_clocking = Storage::Disk::MFMController::preferred_clocking();
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if(mfm_controller_preferred_clocking != ClockingHint::Preference::None) return mfm_controller_preferred_clocking;
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return is_sleeping_ ? ClockingHint::Preference::None : ClockingHint::Preference::JustInTime;
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}
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void i8272::run_for(Cycles cycles) {
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Storage::Disk::MFMController::run_for(cycles);
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if(is_sleeping_) return;
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// check for an expired timer
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if(delay_time_ > 0) {
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if(cycles.as_integral() >= delay_time_) {
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delay_time_ = 0;
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posit_event(static_cast<int>(Event8272::Timer));
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} else {
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delay_time_ -= cycles.as_integral();
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}
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}
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// update seek status of any drives presently seeking
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if(drives_seeking_) {
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int drives_left = drives_seeking_;
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for(int c = 0; c < 4; c++) {
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if(drives_[c].phase == Drive::Seeking) {
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drives_[c].step_rate_counter += cycles.as_integral();
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auto steps = drives_[c].step_rate_counter / (8000 * step_rate_time_);
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drives_[c].step_rate_counter %= (8000 * step_rate_time_);
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while(steps--) {
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// Perform a step.
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int direction = (drives_[c].target_head_position < drives_[c].head_position) ? -1 : 1;
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LOG("Target " << PADDEC(0) << drives_[c].target_head_position << " versus believed " << static_cast<int>(drives_[c].head_position));
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select_drive(c);
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get_drive().step(Storage::Disk::HeadPosition(direction));
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if(drives_[c].target_head_position >= 0) drives_[c].head_position += direction;
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// Check for completion.
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if(seek_is_satisfied(c)) {
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drives_[c].phase = Drive::CompletedSeeking;
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drives_seeking_--;
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break;
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}
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}
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drives_left--;
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if(!drives_left) break;
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}
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}
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}
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// check for any head unloads
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if(head_timers_running_) {
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int timers_left = head_timers_running_;
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for(int c = 0; c < 8; c++) {
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int drive = (c >> 1);
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int head = c&1;
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if(drives_[drive].head_unload_delay[head] > 0) {
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if(cycles.as_integral() >= drives_[drive].head_unload_delay[head]) {
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drives_[drive].head_unload_delay[head] = 0;
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drives_[drive].head_is_loaded[head] = false;
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head_timers_running_--;
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} else {
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drives_[drive].head_unload_delay[head] -= cycles.as_integral();
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}
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timers_left--;
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if(!timers_left) break;
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}
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}
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}
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// check for busy plus ready disabled
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if(is_executing_ && !get_drive().get_is_ready()) {
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posit_event(static_cast<int>(Event8272::NoLongerReady));
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}
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is_sleeping_ = !delay_time_ && !drives_seeking_ && !head_timers_running_;
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if(is_sleeping_) update_clocking_observer();
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}
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void i8272::write(int address, uint8_t value) {
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// don't consider attempted sets to the status register
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if(!address) return;
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// if not ready for commands, do nothing
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if(!DataRequest() || DataDirectionToProcessor()) return;
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if(expects_input_) {
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input_ = value;
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has_input_ = true;
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ResetDataRequest();
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} else {
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// accumulate latest byte in the command byte sequence
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command_.push_back(value);
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posit_event(static_cast<int>(Event8272::CommandByte));
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}
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}
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uint8_t i8272::read(int address) {
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if(address) {
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if(result_stack_.empty()) return 0xff;
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uint8_t result = result_stack_.back();
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result_stack_.pop_back();
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if(result_stack_.empty()) posit_event(static_cast<int>(Event8272::ResultEmpty));
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return result;
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} else {
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return main_status_;
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}
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}
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#define BEGIN_SECTION() switch(resume_point_) { default:
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#define END_SECTION() }
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#define MS_TO_CYCLES(x) x * 8000
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#define WAIT_FOR_EVENT(mask) resume_point_ = __LINE__; interesting_event_mask_ = static_cast<int>(mask); return; case __LINE__:
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#define WAIT_FOR_TIME(ms) resume_point_ = __LINE__; interesting_event_mask_ = static_cast<int>(Event8272::Timer); delay_time_ = MS_TO_CYCLES(ms); is_sleeping_ = false; update_clocking_observer(); case __LINE__: if(delay_time_) return;
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#define PASTE(x, y) x##y
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#define CONCAT(x, y) PASTE(x, y)
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#define FIND_HEADER() \
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set_data_mode(DataMode::Scanning); \
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CONCAT(find_header, __LINE__): WAIT_FOR_EVENT(static_cast<int>(Event::Token) | static_cast<int>(Event::IndexHole)); \
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if(event_type == static_cast<int>(Event::IndexHole)) { index_hole_limit_--; } \
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else if(get_latest_token().type == Token::ID) goto CONCAT(header_found, __LINE__); \
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\
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if(index_hole_limit_) goto CONCAT(find_header, __LINE__); \
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CONCAT(header_found, __LINE__): (void)0;\
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#define FIND_DATA() \
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set_data_mode(DataMode::Scanning); \
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CONCAT(find_data, __LINE__): WAIT_FOR_EVENT(static_cast<int>(Event::Token) | static_cast<int>(Event::IndexHole)); \
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if(event_type == static_cast<int>(Event::Token)) { \
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if(get_latest_token().type == Token::Byte || get_latest_token().type == Token::Sync) goto CONCAT(find_data, __LINE__); \
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}
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#define READ_HEADER() \
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distance_into_section_ = 0; \
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set_data_mode(DataMode::Reading); \
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CONCAT(read_header, __LINE__): WAIT_FOR_EVENT(Event::Token); \
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header_[distance_into_section_] = get_latest_token().byte_value; \
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distance_into_section_++; \
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if(distance_into_section_ < 6) goto CONCAT(read_header, __LINE__); \
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#define SET_DRIVE_HEAD_MFM() \
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active_drive_ = command_[1]&3; \
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active_head_ = (command_[1] >> 2)&1; \
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status_[0] = (command_[1]&7); \
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select_drive(active_drive_); \
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get_drive().set_head(active_head_); \
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set_is_double_density(command_[0] & 0x40);
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#define WAIT_FOR_BYTES(n) \
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distance_into_section_ = 0; \
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CONCAT(wait_bytes, __LINE__): WAIT_FOR_EVENT(Event::Token); \
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if(get_latest_token().type == Token::Byte) distance_into_section_++; \
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if(distance_into_section_ < (n)) goto CONCAT(wait_bytes, __LINE__);
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#define LOAD_HEAD() \
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if(!drives_[active_drive_].head_is_loaded[active_head_]) { \
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drives_[active_drive_].head_is_loaded[active_head_] = true; \
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WAIT_FOR_TIME(head_load_time_); \
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} else { \
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if(drives_[active_drive_].head_unload_delay[active_head_] > 0) { \
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drives_[active_drive_].head_unload_delay[active_head_] = 0; \
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head_timers_running_--; \
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} \
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}
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#define SCHEDULE_HEAD_UNLOAD() \
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if(drives_[active_drive_].head_is_loaded[active_head_]) {\
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if(drives_[active_drive_].head_unload_delay[active_head_] == 0) { \
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head_timers_running_++; \
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is_sleeping_ = false; \
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update_clocking_observer(); \
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} \
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drives_[active_drive_].head_unload_delay[active_head_] = MS_TO_CYCLES(head_unload_time_);\
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}
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void i8272::posit_event(int event_type) {
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if(event_type == static_cast<int>(Event::IndexHole)) index_hole_count_++;
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if(event_type == static_cast<int>(Event8272::NoLongerReady)) {
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SetNotReady();
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goto abort;
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}
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if(!(interesting_event_mask_ & event_type)) return;
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interesting_event_mask_ &= ~event_type;
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BEGIN_SECTION();
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// Resets busy and non-DMA execution, clears the command buffer, sets the data mode to scanning and flows
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// into wait_for_complete_command_sequence.
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wait_for_command:
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expects_input_ = false;
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set_data_mode(Storage::Disk::MFMController::DataMode::Scanning);
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ResetBusy();
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ResetNonDMAExecution();
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command_.clear();
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// Sets the data request bit, and waits for a byte. Then sets the busy bit. Continues accepting bytes
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// until it has a quantity that make up an entire command, then resets the data request bit and
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// branches to that command.
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wait_for_complete_command_sequence:
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SetDataRequest();
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SetDataDirectionFromProcessor();
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WAIT_FOR_EVENT(Event8272::CommandByte)
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SetBusy();
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static constexpr std::size_t required_lengths[32] = {
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0, 0, 9, 3, 2, 9, 9, 2,
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1, 9, 2, 0, 9, 6, 0, 3,
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0, 9, 0, 0, 0, 0, 0, 0,
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0, 9, 0, 0, 0, 9, 0, 0,
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};
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if(command_.size() < required_lengths[command_[0] & 0x1f]) goto wait_for_complete_command_sequence;
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if(command_.size() == 9) {
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cylinder_ = command_[2];
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head_ = command_[3];
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sector_ = command_[4];
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size_ = command_[5];
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}
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ResetDataRequest();
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status_[0] = status_[1] = status_[2] = 0;
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// If this is not clearly a command that's safe to carry out in parallel to a seek, end all seeks.
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switch(command_[0] & 0x1f) {
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case CommandReadData:
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case CommandReadDeletedData:
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case CommandWriteData:
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case CommandWriteDeletedData:
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case CommandReadTrack:
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case CommandReadID:
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case CommandFormatTrack:
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case CommandScanLow:
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case CommandScanLowOrEqual:
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case CommandScanHighOrEqual:
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is_access_command_ = true;
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break;
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default:
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is_access_command_ = false;
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break;
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}
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if(is_access_command_) {
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for(int c = 0; c < 4; c++) {
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if(drives_[c].phase == Drive::Seeking) {
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drives_[c].phase = Drive::NotSeeking;
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drives_seeking_--;
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}
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}
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// Establishes the drive and head being addressed, and whether in double density mode; populates the internal
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// cylinder, head, sector and size registers from the command stream.
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is_executing_ = true;
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if(!dma_mode_) SetNonDMAExecution();
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SET_DRIVE_HEAD_MFM();
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LOAD_HEAD();
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if(!get_drive().get_is_ready()) {
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SetNotReady();
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goto abort;
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}
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}
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// Jump to the proper place.
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switch(command_[0] & 0x1f) {
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case CommandReadData:
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case CommandReadDeletedData:
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goto read_data;
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case CommandWriteData:
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case CommandWriteDeletedData:
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goto write_data;
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case CommandReadTrack: goto read_track;
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case CommandReadID: goto read_id;
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case CommandFormatTrack: goto format_track;
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case CommandScanLow: goto scan_low;
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case CommandScanLowOrEqual: goto scan_low_or_equal;
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case CommandScanHighOrEqual: goto scan_high_or_equal;
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case CommandRecalibrate: goto recalibrate;
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case CommandSeek: goto seek;
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case CommandSenseInterruptStatus: goto sense_interrupt_status;
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case CommandSpecify: goto specify;
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case CommandSenseDriveStatus: goto sense_drive_status;
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default: goto invalid;
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}
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// Decodes drive, head and density, loads the head, loads the internal cylinder, head, sector and size registers,
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// and searches for a sector that meets those criteria. If one is found, inspects the instruction in use and
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// jumps to an appropriate handler.
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read_write_find_header:
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// Sets a maximum index hole limit of 2 then performs a find header/read header loop, continuing either until
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// the index hole limit is breached or a sector is found with a cylinder, head, sector and size equal to the
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// values in the internal registers.
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index_hole_limit_ = 2;
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// LOG("Seeking " << PADDEC(0) << cylinder_ << " " << head_ " " << sector_ << " " << size_);
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find_next_sector:
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FIND_HEADER();
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if(!index_hole_limit_) {
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// Two index holes have passed wihout finding the header sought.
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// LOG("Not found");
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SetNoData();
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goto abort;
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}
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index_hole_count_ = 0;
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// LOG("Header");
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READ_HEADER();
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if(index_hole_count_) {
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// This implies an index hole was sighted within the header. Error out.
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SetEndOfCylinder();
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goto abort;
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}
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if(get_crc_generator().get_value()) {
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// This implies a CRC error in the header; mark as such but continue.
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SetDataError();
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}
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// LOG("Considering << PADHEX(2) << header_[0] << " " << header_[1] << " " << header_[2] << " " << header_[3] << " [" << get_crc_generator().get_value() << "]");
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if(header_[0] != cylinder_ || header_[1] != head_ || header_[2] != sector_ || header_[3] != size_) goto find_next_sector;
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// Branch to whatever is supposed to happen next
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// LOG("Proceeding");
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switch(command_[0] & 0x1f) {
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case CommandReadData:
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case CommandReadDeletedData:
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goto read_data_found_header;
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case CommandWriteData: // write data
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case CommandWriteDeletedData: // write deleted data
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goto write_data_found_header;
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}
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// Performs the read data or read deleted data command.
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read_data:
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LOG(PADHEX(2) << "Read [deleted] data ["
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<< static_cast<int>(command_[2]) << " "
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<< static_cast<int>(command_[3]) << " "
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<< static_cast<int>(command_[4]) << " "
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<< static_cast<int>(command_[5]) << " ... "
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<< static_cast<int>(command_[6]) << " "
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<< static_cast<int>(command_[8]) << "]");
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read_next_data:
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goto read_write_find_header;
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// Finds the next data block and sets data mode to reading, setting an error flag if the on-disk deleted
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// flag doesn't match the sort the command was looking for.
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read_data_found_header:
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FIND_DATA();
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ClearControlMark();
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if(event_type == static_cast<int>(Event::Token)) {
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if(get_latest_token().type != Token::Data && get_latest_token().type != Token::DeletedData) {
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// Something other than a data mark came next, impliedly an ID or index mark.
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SetMissingAddressMark();
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SetMissingDataAddressMark();
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goto abort; // TODO: or read_next_data?
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} else {
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if((get_latest_token().type == Token::Data) != ((command_[0] & 0x1f) == CommandReadData)) {
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if(!(command_[0]&0x20)) {
|
|
// SK is not set; set the error flag but read this sector before finishing.
|
|
SetControlMark();
|
|
} else {
|
|
// SK is set; skip this sector.
|
|
goto read_next_data;
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
// An index hole appeared before the data mark.
|
|
SetEndOfCylinder();
|
|
goto abort; // TODO: or read_next_data?
|
|
}
|
|
|
|
distance_into_section_ = 0;
|
|
set_data_mode(Reading);
|
|
|
|
// Waits for the next token, then supplies it to the CPU by: (i) setting data request and direction; and (ii) resetting
|
|
// data request once the byte has been taken. Continues until all bytes have been read.
|
|
//
|
|
// TODO: consider DTL.
|
|
read_data_get_byte:
|
|
WAIT_FOR_EVENT(static_cast<int>(Event::Token) | static_cast<int>(Event::IndexHole));
|
|
if(event_type == static_cast<int>(Event::Token)) {
|
|
result_stack_.push_back(get_latest_token().byte_value);
|
|
distance_into_section_++;
|
|
SetDataRequest();
|
|
SetDataDirectionToProcessor();
|
|
WAIT_FOR_EVENT(static_cast<int>(Event8272::ResultEmpty) | static_cast<int>(Event::Token) | static_cast<int>(Event::IndexHole));
|
|
}
|
|
switch(event_type) {
|
|
case static_cast<int>(Event8272::ResultEmpty): // The caller read the byte in time; proceed as normal.
|
|
ResetDataRequest();
|
|
if(distance_into_section_ < (128 << size_)) goto read_data_get_byte;
|
|
break;
|
|
case static_cast<int>(Event::Token): // The caller hasn't read the old byte yet and a new one has arrived
|
|
SetOverrun();
|
|
goto abort;
|
|
break;
|
|
case static_cast<int>(Event::IndexHole):
|
|
SetEndOfCylinder();
|
|
goto abort;
|
|
break;
|
|
}
|
|
|
|
// read CRC, without transferring it, then check it
|
|
WAIT_FOR_EVENT(Event::Token);
|
|
WAIT_FOR_EVENT(Event::Token);
|
|
if(get_crc_generator().get_value()) {
|
|
// This implies a CRC error in the sector; mark as such and temrinate.
|
|
SetDataError();
|
|
SetDataFieldDataError();
|
|
goto abort;
|
|
}
|
|
|
|
// check whether that's it: either the final requested sector has been read, or because
|
|
// a sector that was [/wasn't] marked as deleted when it shouldn't [/should] have been
|
|
if(sector_ != command_[6] && !ControlMark()) {
|
|
sector_++;
|
|
goto read_next_data;
|
|
}
|
|
|
|
// For a final result phase, post the standard ST0, ST1, ST2, C, H, R, N
|
|
goto post_st012chrn;
|
|
|
|
write_data:
|
|
LOG(PADHEX(2) << "Write [deleted] data ["
|
|
<< static_cast<int>(command_[2]) << " "
|
|
<< static_cast<int>(command_[3]) << " "
|
|
<< static_cast<int>(command_[4]) << " "
|
|
<< static_cast<int>(command_[5]) << " ... "
|
|
<< static_cast<int>(command_[6]) << " "
|
|
<< static_cast<int>(command_[8]) << "]");
|
|
|
|
if(get_drive().get_is_read_only()) {
|
|
SetNotWriteable();
|
|
goto abort;
|
|
}
|
|
|
|
write_next_data:
|
|
goto read_write_find_header;
|
|
|
|
write_data_found_header:
|
|
WAIT_FOR_BYTES(get_is_double_density() ? 22 : 11);
|
|
begin_writing(true);
|
|
|
|
write_id_data_joiner((command_[0] & 0x1f) == CommandWriteDeletedData, true);
|
|
|
|
SetDataDirectionFromProcessor();
|
|
SetDataRequest();
|
|
expects_input_ = true;
|
|
distance_into_section_ = 0;
|
|
|
|
write_loop:
|
|
WAIT_FOR_EVENT(Event::DataWritten);
|
|
if(!has_input_) {
|
|
SetOverrun();
|
|
goto abort;
|
|
}
|
|
write_byte(input_);
|
|
has_input_ = false;
|
|
distance_into_section_++;
|
|
if(distance_into_section_ < (128 << size_)) {
|
|
SetDataRequest();
|
|
goto write_loop;
|
|
}
|
|
|
|
LOG("Wrote " << PADDEC(0) << distance_into_section_ << " bytes");
|
|
write_crc();
|
|
expects_input_ = false;
|
|
WAIT_FOR_EVENT(Event::DataWritten);
|
|
end_writing();
|
|
|
|
if(sector_ != command_[6]) {
|
|
sector_++;
|
|
goto write_next_data;
|
|
}
|
|
|
|
goto post_st012chrn;
|
|
|
|
// Performs the read ID command.
|
|
read_id:
|
|
// Establishes the drive and head being addressed, and whether in double density mode.
|
|
LOG(PADHEX(2) << "Read ID [" << static_cast<int>(command_[0]) << " " << static_cast<int>(command_[1]) << "]");
|
|
|
|
// Sets a maximum index hole limit of 2 then waits either until it finds a header mark or sees too many index holes.
|
|
// If a header mark is found, reads in the following bytes that produce a header. Otherwise branches to data not found.
|
|
index_hole_limit_ = 2;
|
|
FIND_HEADER();
|
|
if(!index_hole_limit_) {
|
|
SetMissingAddressMark();
|
|
goto abort;
|
|
}
|
|
READ_HEADER();
|
|
|
|
// Sets internal registers from the discovered header and posts the standard ST0, ST1, ST2, C, H, R, N.
|
|
cylinder_ = header_[0];
|
|
head_ = header_[1];
|
|
sector_ = header_[2];
|
|
size_ = header_[3];
|
|
|
|
goto post_st012chrn;
|
|
|
|
// Performs read track.
|
|
read_track:
|
|
LOG(PADHEX(2) << "Read track ["
|
|
<< static_cast<int>(command_[2]) << " "
|
|
<< static_cast<int>(command_[3]) << " "
|
|
<< static_cast<int>(command_[4]) << " "
|
|
<< static_cast<int>(command_[5]) << "]");
|
|
|
|
// Wait for the index hole.
|
|
WAIT_FOR_EVENT(Event::IndexHole);
|
|
|
|
sector_ = 0;
|
|
index_hole_limit_ = 2;
|
|
|
|
// While not index hole again, stream all sector contents until EOT sectors have been read.
|
|
read_track_next_sector:
|
|
FIND_HEADER();
|
|
if(!index_hole_limit_) {
|
|
if(!sector_) {
|
|
SetMissingAddressMark();
|
|
goto abort;
|
|
} else {
|
|
goto post_st012chrn;
|
|
}
|
|
}
|
|
READ_HEADER();
|
|
|
|
FIND_DATA();
|
|
distance_into_section_ = 0;
|
|
SetDataDirectionToProcessor();
|
|
read_track_get_byte:
|
|
WAIT_FOR_EVENT(Event::Token);
|
|
result_stack_.push_back(get_latest_token().byte_value);
|
|
distance_into_section_++;
|
|
SetDataRequest();
|
|
// TODO: other possible exit conditions; find a way to merge with the read_data version of this.
|
|
WAIT_FOR_EVENT(static_cast<int>(Event8272::ResultEmpty));
|
|
ResetDataRequest();
|
|
if(distance_into_section_ < (128 << header_[2])) goto read_track_get_byte;
|
|
|
|
sector_++;
|
|
if(sector_ < command_[6]) goto read_track_next_sector;
|
|
|
|
goto post_st012chrn;
|
|
|
|
// Performs format [/write] track.
|
|
format_track:
|
|
LOG("Format track");
|
|
if(get_drive().get_is_read_only()) {
|
|
SetNotWriteable();
|
|
goto abort;
|
|
}
|
|
|
|
// Wait for the index hole.
|
|
WAIT_FOR_EVENT(Event::IndexHole);
|
|
index_hole_count_ = 0;
|
|
begin_writing(true);
|
|
|
|
// Write start-of-track.
|
|
write_start_of_track();
|
|
WAIT_FOR_EVENT(Event::DataWritten);
|
|
sector_ = 0;
|
|
|
|
format_track_write_sector:
|
|
write_id_joiner();
|
|
|
|
// Write the sector header, obtaining its contents
|
|
// from the processor.
|
|
SetDataDirectionFromProcessor();
|
|
SetDataRequest();
|
|
expects_input_ = true;
|
|
distance_into_section_ = 0;
|
|
format_track_write_header:
|
|
WAIT_FOR_EVENT(static_cast<int>(Event::DataWritten) | static_cast<int>(Event::IndexHole));
|
|
switch(event_type) {
|
|
case static_cast<int>(Event::IndexHole):
|
|
SetOverrun();
|
|
goto abort;
|
|
break;
|
|
case static_cast<int>(Event::DataWritten):
|
|
header_[distance_into_section_] = input_;
|
|
write_byte(input_);
|
|
has_input_ = false;
|
|
distance_into_section_++;
|
|
if(distance_into_section_ < 4) {
|
|
SetDataRequest();
|
|
goto format_track_write_header;
|
|
}
|
|
break;
|
|
}
|
|
|
|
LOG(PADHEX(2) << "W:"
|
|
<< static_cast<int>(header_[0]) << " "
|
|
<< static_cast<int>(header_[1]) << " "
|
|
<< static_cast<int>(header_[2]) << " "
|
|
<< static_cast<int>(header_[3]) << ", "
|
|
<< get_crc_generator().get_value());
|
|
write_crc();
|
|
|
|
// Write the sector body.
|
|
write_id_data_joiner(false, false);
|
|
write_n_bytes(128 << command_[2], command_[5]);
|
|
write_crc();
|
|
|
|
// Write the prescribed gap.
|
|
write_n_bytes(command_[4], get_is_double_density() ? 0x4e : 0xff);
|
|
|
|
// Consider repeating.
|
|
sector_++;
|
|
if(sector_ < command_[3] && !index_hole_count_)
|
|
goto format_track_write_sector;
|
|
|
|
// Otherwise, pad out to the index hole.
|
|
format_track_pad:
|
|
write_byte(get_is_double_density() ? 0x4e : 0xff);
|
|
WAIT_FOR_EVENT(static_cast<int>(Event::DataWritten) | static_cast<int>(Event::IndexHole));
|
|
if(event_type != static_cast<int>(Event::IndexHole)) goto format_track_pad;
|
|
|
|
end_writing();
|
|
|
|
cylinder_ = header_[0];
|
|
head_ = header_[1];
|
|
sector_ = header_[2] + 1;
|
|
size_ = header_[3];
|
|
|
|
goto post_st012chrn;
|
|
|
|
scan_low:
|
|
ERROR("Scan low unimplemented!!");
|
|
goto wait_for_command;
|
|
|
|
scan_low_or_equal:
|
|
ERROR("Scan low or equal unimplemented!!");
|
|
goto wait_for_command;
|
|
|
|
scan_high_or_equal:
|
|
ERROR("Scan high or equal unimplemented!!");
|
|
goto wait_for_command;
|
|
|
|
// Performs both recalibrate and seek commands. These commands occur asynchronously, so the actual work
|
|
// occurs in ::run_for; this merely establishes that seeking should be ongoing.
|
|
recalibrate:
|
|
seek:
|
|
{
|
|
int drive = command_[1]&3;
|
|
select_drive(drive);
|
|
|
|
// Increment the seeking count if this drive wasn't already seeking.
|
|
if(drives_[drive].phase != Drive::Seeking) {
|
|
drives_seeking_++;
|
|
is_sleeping_ = false;
|
|
update_clocking_observer();
|
|
}
|
|
|
|
// Set currently seeking, with a step to occur right now (yes, it sounds like jamming these
|
|
// in could damage your drive motor).
|
|
drives_[drive].phase = Drive::Seeking;
|
|
drives_[drive].step_rate_counter = 8000 * step_rate_time_;
|
|
drives_[drive].steps_taken = 0;
|
|
drives_[drive].seek_failed = false;
|
|
main_status_ |= 1 << (command_[1]&3);
|
|
|
|
// If this is a seek, set the processor-supplied target location; otherwise it is a recalibrate,
|
|
// which means resetting the current state now but aiming to hit '-1' (which the stepping code
|
|
// up in run_for understands to mean 'keep going until track 0 is active').
|
|
if(command_.size() > 2) {
|
|
drives_[drive].target_head_position = command_[2];
|
|
LOG(PADHEX(2) << "Seek to " << static_cast<int>(command_[2]));
|
|
} else {
|
|
drives_[drive].target_head_position = -1;
|
|
drives_[drive].head_position = 0;
|
|
LOG("Recalibrate");
|
|
}
|
|
|
|
// Check whether any steps are even needed; if not then mark as completed already.
|
|
if(seek_is_satisfied(drive)) {
|
|
drives_[drive].phase = Drive::CompletedSeeking;
|
|
drives_seeking_--;
|
|
}
|
|
}
|
|
goto wait_for_command;
|
|
|
|
// Performs sense interrupt status.
|
|
sense_interrupt_status:
|
|
LOG("Sense interrupt status");
|
|
{
|
|
// Find the first drive that is in the CompletedSeeking state.
|
|
int found_drive = -1;
|
|
for(int c = 0; c < 4; c++) {
|
|
if(drives_[c].phase == Drive::CompletedSeeking) {
|
|
found_drive = c;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// If a drive was found, return its results. Otherwise return a single 0x80.
|
|
if(found_drive != -1) {
|
|
drives_[found_drive].phase = Drive::NotSeeking;
|
|
status_[0] = static_cast<uint8_t>(found_drive);
|
|
main_status_ &= ~(1 << found_drive);
|
|
SetSeekEnd();
|
|
|
|
result_stack_ = { drives_[found_drive].head_position, status_[0]};
|
|
} else {
|
|
result_stack_ = { 0x80 };
|
|
}
|
|
}
|
|
goto post_result;
|
|
|
|
// Performs specify.
|
|
specify:
|
|
// Just store the values, and terminate the command.
|
|
LOG("Specify");
|
|
step_rate_time_ = 16 - (command_[1] >> 4); // i.e. 1 to 16ms
|
|
head_unload_time_ = (command_[1] & 0x0f) << 4; // i.e. 16 to 240ms
|
|
head_load_time_ = command_[2] & ~1; // i.e. 2 to 254 ms in increments of 2ms
|
|
|
|
if(!head_unload_time_) head_unload_time_ = 16;
|
|
if(!head_load_time_) head_load_time_ = 2;
|
|
dma_mode_ = !(command_[2] & 1);
|
|
goto wait_for_command;
|
|
|
|
sense_drive_status:
|
|
LOG("Sense drive status");
|
|
{
|
|
int drive = command_[1] & 3;
|
|
select_drive(drive);
|
|
result_stack_= {
|
|
static_cast<uint8_t>(
|
|
(command_[1] & 7) | // drive and head number
|
|
0x08 | // single sided
|
|
(get_drive().get_is_track_zero() ? 0x10 : 0x00) |
|
|
(get_drive().get_is_ready() ? 0x20 : 0x00) |
|
|
(get_drive().get_is_read_only() ? 0x40 : 0x00)
|
|
)
|
|
};
|
|
}
|
|
goto post_result;
|
|
|
|
// Performs any invalid command.
|
|
invalid:
|
|
// A no-op, but posts ST0 (but which ST0?)
|
|
result_stack_ = {0x80};
|
|
goto post_result;
|
|
|
|
// Sets abnormal termination of the current command and proceeds to an ST0, ST1, ST2, C, H, R, N result phase.
|
|
abort:
|
|
end_writing();
|
|
SetAbnormalTermination();
|
|
goto post_st012chrn;
|
|
|
|
// Posts ST0, ST1, ST2, C, H, R and N as a result phase.
|
|
post_st012chrn:
|
|
SCHEDULE_HEAD_UNLOAD();
|
|
|
|
result_stack_ = {size_, sector_, head_, cylinder_, status_[2], status_[1], status_[0]};
|
|
|
|
goto post_result;
|
|
|
|
// Posts whatever is in result_stack_ as a result phase. Be aware that it is a stack, so the
|
|
// last thing in it will be returned first.
|
|
post_result:
|
|
LOGNBR(PADHEX(2) << "Result to " << static_cast<int>(command_[0] & 0x1f) << ", main " << static_cast<int>(main_status_) << "; ");
|
|
for(std::size_t c = 0; c < result_stack_.size(); c++) {
|
|
LOGNBR(" " << static_cast<int>(result_stack_[result_stack_.size() - 1 - c]));
|
|
}
|
|
LOGNBR(std::endl);
|
|
|
|
// Set ready to send data to the processor, no longer in non-DMA execution phase.
|
|
is_executing_ = false;
|
|
ResetNonDMAExecution();
|
|
SetDataRequest();
|
|
SetDataDirectionToProcessor();
|
|
|
|
// The actual stuff of unwinding result_stack_ is handled by ::read; wait
|
|
// until the processor has read all result bytes.
|
|
WAIT_FOR_EVENT(Event8272::ResultEmpty);
|
|
|
|
// Reset data direction and end the command.
|
|
goto wait_for_command;
|
|
|
|
END_SECTION()
|
|
}
|
|
|
|
bool i8272::seek_is_satisfied(int drive) {
|
|
return (drives_[drive].target_head_position == drives_[drive].head_position) ||
|
|
(drives_[drive].target_head_position == -1 && get_drive().get_is_track_zero());
|
|
}
|
|
|
|
void i8272::set_dma_acknowledge(bool dack) {
|
|
}
|
|
|
|
void i8272::set_terminal_count(bool tc) {
|
|
}
|
|
|
|
void i8272::set_data_input(uint8_t value) {
|
|
}
|
|
|
|
uint8_t i8272::get_data_output() {
|
|
return 0xff;
|
|
}
|