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Factor out the stuff of accumulating and dissecting commands.

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This commit is contained in:
Thomas Harte 2023-11-24 18:24:58 -05:00
parent d5c30e3175
commit af70c8847d
4 changed files with 308 additions and 126 deletions
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221
Components/8272/CommandDecoder.hpp Normal file
View File

@ -0,0 +1,221 @@
//
// CommandDecoder.hpp
// Clock Signal
//
// Created by Thomas Harte on 24/11/2023.
// Copyright © 2023 Thomas Harte. All rights reserved.
//
#ifndef CommandDecoder_hpp
#define CommandDecoder_hpp
#include <cstdint>
#include <cstddef>
#include <vector>
namespace Intel::i8272 {
class CommandDecoder {
public:
enum class Command {
ReadData = 0x06,
ReadDeletedData = 0x0c,
WriteData = 0x05,
WriteDeletedData = 0x09,
ReadTrack = 0x02,
ReadID = 0x0a,
FormatTrack = 0x0d,
ScanLow = 0x11,
ScanLowOrEqual = 0x19,
ScanHighOrEqual = 0x1d,
Recalibrate = 0x07,
Seek = 0x0f,
SenseInterruptStatus = 0x08,
Specify = 0x03,
SenseDriveStatus = 0x04,
Invalid = 0x00,
};
/// Add a byte to the current command.
void push_back(uint8_t byte) {
command_.push_back(byte);
}
/// Reset decoding.
void clear() {
command_.clear();
}
/// @returns @c true if an entire command has been received; @c false if further bytes are needed.
bool has_command() const {
if(!command_.size()) {
return false;
}
static constexpr std::size_t required_lengths[32] = {
0, 0, 9, 3, 2, 9, 9, 2,
1, 9, 2, 0, 9, 6, 0, 3,
0, 9, 0, 0, 0, 0, 0, 0,
0, 9, 0, 0, 0, 9, 0, 0,
};
return command_.size() >= required_lengths[command_[0] & 0x1f];
}
/// @returns The command requested. Valid only if @c has_command() is @c true.
Command command() const {
const auto command = Command(command_[0] & 0x1f);
switch(command) {
case Command::ReadData: case Command::ReadDeletedData:
case Command::WriteData: case Command::WriteDeletedData:
case Command::ReadTrack: case Command::ReadID:
case Command::FormatTrack:
case Command::ScanLow: case Command::ScanLowOrEqual:
case Command::ScanHighOrEqual:
case Command::Recalibrate: case Command::Seek:
case Command::SenseInterruptStatus:
case Command::Specify: case Command::SenseDriveStatus:
return command;
default: return Command::Invalid;
}
}
//
// Commands that specify geometry; i.e.
//
// * ReadData;
// * ReadDeletedData;
// * WriteData;
// * WriteDeletedData;
// * ReadTrack;
// * ScanEqual;
// * ScanLowOrEqual;
// * ScanHighOrEqual.
//
/// @returns @c true if this command specifies geometry, in which case geomtry() is well-defined.
/// @c false otherwise.
bool has_geometry() const { return command_.size() == 9; }
struct Geometry {
uint8_t cylinder, head, sector, size, end_of_track;
};
Geometry geometry() const {
Geometry result;
result.cylinder = command_[2];
result.head = command_[3];
result.sector = command_[4];
result.size = command_[5];
result.end_of_track = command_[6];
return result;
}
//
// Commands that imply data access; i.e.
//
// * ReadData;
// * ReadDeletedData;
// * WriteData;
// * WriteDeletedData;
// * ReadTrack;
// * ReadID;
// * FormatTrack;
// * ScanLow;
// * ScanLowOrEqual;
// * ScanHighOrEqual.
//
/// @returns @c true if this command involves reading or writing data, in which case target() will be valid.
/// @c false otherwise.
bool is_access_command() const {
switch(command()) {
case Command::ReadData: case Command::ReadDeletedData:
case Command::WriteData: case Command::WriteDeletedData:
case Command::ReadTrack: case Command::ReadID:
case Command::FormatTrack:
case Command::ScanLow: case Command::ScanLowOrEqual:
case Command::ScanHighOrEqual:
return true;
default:
return false;
}
}
struct AccessTarget {
uint8_t drive, head;
bool mfm, skip_deleted;
};
AccessTarget target() const {
AccessTarget result;
result.drive = command_[1] & 0x03;
result.head = (command_[1] >> 2) & 0x01;
result.mfm = command_[0] & 0x40;
result.skip_deleted = command_[0] & 0x20;
return result;
}
uint8_t drive_head() const {
return command_[1]&7;
}
//
// Command::FormatTrack
//
struct FormatSpecs {
uint8_t bytes_per_sector;
uint8_t sectors_per_track;
uint8_t gap3_length;
uint8_t filler;
};
FormatSpecs format_specs() const {
FormatSpecs result;
result.bytes_per_sector = command_[2];
result.sectors_per_track = command_[3];
result.gap3_length = command_[4];
result.filler = command_[5];
return result;
}
//
// Command::Seek
//
/// @returns The desired target track.
uint8_t seek_target() const {
return command_[2];
}
//
// Command::Specify
//
struct SpecifySpecs {
// The below are all in milliseconds.
uint8_t step_rate_time;
uint8_t head_unload_time;
uint8_t head_load_time;
bool use_dma;
};
SpecifySpecs specify_specs() const {
SpecifySpecs result;
result.step_rate_time = 16 - (command_[1] >> 4); // i.e. 1 to 16ms
result.head_unload_time = uint8_t((command_[1] & 0x0f) << 4); // i.e. 16 to 240ms
result.head_load_time = command_[2] & ~1; // i.e. 2 to 254 ms in increments of 2ms
result.use_dma = !(command_[2] & 1);
return result;
}
private:
std::vector<uint8_t> command_;
};
}
#endif /* CommandDecoder_hpp */

207
Components/8272/i8272.cpp
View File

@ -53,29 +53,6 @@ using namespace Intel::i8272;
#define SetBadCylinder() (status_[2] |= 0x02)
#define SetMissingDataAddressMark() (status_[2] |= 0x01)
namespace {
const uint8_t CommandReadData = 0x06;
const uint8_t CommandReadDeletedData = 0x0c;
const uint8_t CommandWriteData = 0x05;
const uint8_t CommandWriteDeletedData = 0x09;
const uint8_t CommandReadTrack = 0x02;
const uint8_t CommandReadID = 0x0a;
const uint8_t CommandFormatTrack = 0x0d;
const uint8_t CommandScanLow = 0x11;
const uint8_t CommandScanLowOrEqual = 0x19;
const uint8_t CommandScanHighOrEqual = 0x1d;
const uint8_t CommandRecalibrate = 0x07;
const uint8_t CommandSeek = 0x0f;
const uint8_t CommandSenseInterruptStatus = 0x08;
const uint8_t CommandSpecify = 0x03;
const uint8_t CommandSenseDriveStatus = 0x04;
}
i8272::i8272(BusHandler &bus_handler, Cycles clock_rate) :
Storage::Disk::MFMController(clock_rate),
bus_handler_(bus_handler) {
@ -233,12 +210,12 @@ uint8_t i8272::read(int address) {
if(distance_into_section_ < 6) goto CONCAT(read_header, __LINE__); \
#define SET_DRIVE_HEAD_MFM() \
active_drive_ = command_[1]&3; \
active_head_ = (command_[1] >> 2)&1; \
status_[0] = (command_[1]&7); \
active_drive_ = command_.target().drive; \
active_head_ = command_.target().head; \
status_[0] = command_.drive_head(); \
select_drive(active_drive_); \
get_drive().set_head(active_head_); \
set_is_double_density(command_[0] & 0x40);
set_is_double_density(command_.target().mfm);
#define WAIT_FOR_BYTES(n) \
distance_into_section_ = 0; \
@ -296,42 +273,20 @@ void i8272::posit_event(int event_type) {
WAIT_FOR_EVENT(Event8272::CommandByte)
SetBusy();
static constexpr std::size_t required_lengths[32] = {
0, 0, 9, 3, 2, 9, 9, 2,
1, 9, 2, 0, 9, 6, 0, 3,
0, 9, 0, 0, 0, 0, 0, 0,
0, 9, 0, 0, 0, 9, 0, 0,
};
if(command_.size() < required_lengths[command_[0] & 0x1f]) goto wait_for_complete_command_sequence;
if(command_.size() == 9) {
cylinder_ = command_[2];
head_ = command_[3];
sector_ = command_[4];
size_ = command_[5];
if(!command_.has_command()) {
goto wait_for_complete_command_sequence;
}
if(command_.has_geometry() == 9) {
cylinder_ = command_.geometry().cylinder;
head_ = command_.geometry().head;
sector_ = command_.geometry().sector;
size_ = command_.geometry().size;
}
ResetDataRequest();
status_[0] = status_[1] = status_[2] = 0;
// If this is not clearly a command that's safe to carry out in parallel to a seek, end all seeks.
switch(command_[0] & 0x1f) {
case CommandReadData:
case CommandReadDeletedData:
case CommandWriteData:
case CommandWriteDeletedData:
case CommandReadTrack:
case CommandReadID:
case CommandFormatTrack:
case CommandScanLow:
case CommandScanLowOrEqual:
case CommandScanHighOrEqual:
is_access_command_ = true;
break;
default:
is_access_command_ = false;
break;
}
is_access_command_ = command_.is_access_command();
if(is_access_command_) {
for(int c = 0; c < 4; c++) {
@ -353,29 +308,30 @@ void i8272::posit_event(int event_type) {
}
// Jump to the proper place.
switch(command_[0] & 0x1f) {
case CommandReadData:
case CommandReadDeletedData:
using Command = CommandDecoder::Command;
switch(command_.command()) {
case Command::ReadData:
case Command::ReadDeletedData:
goto read_data;
case CommandWriteData:
case CommandWriteDeletedData:
case Command::WriteData:
case Command::WriteDeletedData:
goto write_data;
case CommandReadTrack: goto read_track;
case CommandReadID: goto read_id;
case CommandFormatTrack: goto format_track;
case Command::ReadTrack: goto read_track;
case Command::ReadID: goto read_id;
case Command::FormatTrack: goto format_track;
case CommandScanLow: goto scan_low;
case CommandScanLowOrEqual: goto scan_low_or_equal;
case CommandScanHighOrEqual: goto scan_high_or_equal;
case Command::ScanLow: goto scan_low;
case Command::ScanLowOrEqual: goto scan_low_or_equal;
case Command::ScanHighOrEqual: goto scan_high_or_equal;
case CommandRecalibrate: goto recalibrate;
case CommandSeek: goto seek;
case Command::Recalibrate: goto recalibrate;
case Command::Seek: goto seek;
case CommandSenseInterruptStatus: goto sense_interrupt_status;
case CommandSpecify: goto specify;
case CommandSenseDriveStatus: goto sense_drive_status;
case Command::SenseInterruptStatus: goto sense_interrupt_status;
case Command::Specify: goto specify;
case Command::SenseDriveStatus: goto sense_drive_status;
default: goto invalid;
}
@ -415,26 +371,27 @@ void i8272::posit_event(int event_type) {
// Branch to whatever is supposed to happen next
// LOG("Proceeding");
switch(command_[0] & 0x1f) {
case CommandReadData:
case CommandReadDeletedData:
switch(command_.command()) {
default:
case Command::ReadData:
case Command::ReadDeletedData:
goto read_data_found_header;
case CommandWriteData: // write data
case CommandWriteDeletedData: // write deleted data
case Command::WriteData: // write data
case Command::WriteDeletedData: // write deleted data
goto write_data_found_header;
}
// Performs the read data or read deleted data command.
read_data:
LOG(PADHEX(2) << "Read [deleted] data ["
<< int(command_[2]) << " "
<< int(command_[3]) << " "
<< int(command_[4]) << " "
<< int(command_[5]) << " ... "
<< int(command_[6]) << " "
<< int(command_[8]) << "]");
// LOG(PADHEX(2) << "Read [deleted] data ["
// << int(command_[2]) << " "
// << int(command_[3]) << " "
// << int(command_[4]) << " "
// << int(command_[5]) << " ... "
// << int(command_[6]) << " "
// << int(command_[8]) << "]");
read_next_data:
goto read_write_find_header;
@ -450,8 +407,8 @@ void i8272::posit_event(int event_type) {
SetMissingDataAddressMark();
goto abort; // TODO: or read_next_data?
} else {
if((get_latest_token().type == Token::Data) != ((command_[0] & 0x1f) == CommandReadData)) {
if(!(command_[0]&0x20)) {
if((get_latest_token().type == Token::Data) != (command_.command() == Command::ReadData)) {
if(!command_.target().skip_deleted) {
// SK is not set; set the error flag but read this sector before finishing.
SetControlMark();
} else {
@ -509,7 +466,7 @@ void i8272::posit_event(int event_type) {
// 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()) {
if(sector_ != command_.geometry().end_of_track && !ControlMark()) {
sector_++;
goto read_next_data;
}
@ -518,13 +475,13 @@ void i8272::posit_event(int event_type) {
goto post_st012chrn;
write_data:
LOG(PADHEX(2) << "Write [deleted] data ["
<< int(command_[2]) << " "
<< int(command_[3]) << " "
<< int(command_[4]) << " "
<< int(command_[5]) << " ... "
<< int(command_[6]) << " "
<< int(command_[8]) << "]");
// LOG(PADHEX(2) << "Write [deleted] data ["
// << int(command_[2]) << " "
// << int(command_[3]) << " "
// << int(command_[4]) << " "
// << int(command_[5]) << " ... "
// << int(command_[6]) << " "
// << int(command_[8]) << "]");
if(get_drive().get_is_read_only()) {
SetNotWriteable();
@ -538,7 +495,7 @@ void i8272::posit_event(int event_type) {
WAIT_FOR_BYTES(get_is_double_density() ? 22 : 11);
begin_writing(true);
write_id_data_joiner((command_[0] & 0x1f) == CommandWriteDeletedData, true);
write_id_data_joiner(command_.command() == Command::WriteDeletedData, true);
SetDataDirectionFromProcessor();
SetDataRequest();
@ -565,7 +522,7 @@ void i8272::posit_event(int event_type) {
WAIT_FOR_EVENT(Event::DataWritten);
end_writing();
if(sector_ != command_[6]) {
if(sector_ != command_.geometry().end_of_track) {
sector_++;
goto write_next_data;
}
@ -575,7 +532,7 @@ void i8272::posit_event(int event_type) {
// 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 [" << int(command_[0]) << " " << int(command_[1]) << "]");
// LOG(PADHEX(2) << "Read ID [" << int(command_[0]) << " " << 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.
@ -597,11 +554,11 @@ void i8272::posit_event(int event_type) {
// Performs read track.
read_track:
LOG(PADHEX(2) << "Read track ["
<< int(command_[2]) << " "
<< int(command_[3]) << " "
<< int(command_[4]) << " "
<< int(command_[5]) << "]");
// LOG(PADHEX(2) << "Read track ["
// << int(command_[2]) << " "
// << int(command_[3]) << " "
// << int(command_[4]) << " "
// << int(command_[5]) << "]");
// Wait for the index hole.
WAIT_FOR_EVENT(Event::IndexHole);
@ -636,7 +593,7 @@ void i8272::posit_event(int event_type) {
if(distance_into_section_ < (128 << header_[2])) goto read_track_get_byte;
sector_++;
if(sector_ < command_[6]) goto read_track_next_sector;
if(sector_ < command_.geometry().end_of_track) goto read_track_next_sector;
goto post_st012chrn;
@ -696,15 +653,15 @@ void i8272::posit_event(int event_type) {
// Write the sector body.
write_id_data_joiner(false, false);
write_n_bytes(128 << command_[2], command_[5]);
write_n_bytes(128 << command_.format_specs().bytes_per_sector, command_.format_specs().filler);
write_crc();
// Write the prescribed gap.
write_n_bytes(command_[4], get_is_double_density() ? 0x4e : 0xff);
write_n_bytes(command_.format_specs().gap3_length, get_is_double_density() ? 0x4e : 0xff);
// Consider repeating.
sector_++;
if(sector_ < command_[3] && !index_hole_count_)
if(sector_ < command_.format_specs().sectors_per_track && !index_hole_count_)
goto format_track_write_sector;
// Otherwise, pad out to the index hole.
@ -739,7 +696,7 @@ void i8272::posit_event(int event_type) {
recalibrate:
seek:
{
int drive = command_[1]&3;
const int drive = command_.target().drive;
select_drive(drive);
// Increment the seeking count if this drive wasn't already seeking.
@ -755,14 +712,14 @@ void i8272::posit_event(int event_type) {
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);
main_status_ |= 1 << command_.target().drive;
// 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 " << int(command_[2]));
if(command_.command() != Command::Recalibrate) {
drives_[drive].target_head_position = command_.seek_target();
LOG(PADHEX(2) << "Seek to " << int(command_.seek_target()));
} else {
drives_[drive].target_head_position = -1;
drives_[drive].head_position = 0;
@ -808,24 +765,24 @@ void i8272::posit_event(int event_type) {
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
step_rate_time_ = command_.specify_specs().step_rate_time;
head_unload_time_ = command_.specify_specs().head_unload_time;
head_load_time_ = command_.specify_specs().head_load_time;
if(!head_unload_time_) head_unload_time_ = 16;
if(!head_load_time_) head_load_time_ = 2;
dma_mode_ = !(command_[2] & 1);
dma_mode_ = command_.specify_specs().use_dma;
goto wait_for_command;
sense_drive_status:
LOG("Sense drive status");
{
int drive = command_[1] & 3;
int drive = command_.target().drive;
select_drive(drive);
result_stack_= {
uint8_t(
(command_[1] & 7) | // drive and head number
0x08 | // single sided
(command_.drive_head()) | // 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)
@ -857,11 +814,11 @@ void i8272::posit_event(int event_type) {
// 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 " << int(command_[0] & 0x1f) << ", main " << int(main_status_) << "; ");
for(std::size_t c = 0; c < result_stack_.size(); c++) {
LOGNBR(" " << int(result_stack_[result_stack_.size() - 1 - c]));
}
LOGNBR(std::endl);
// LOGNBR(PADHEX(2) << "Result to " << int(command_[0] & 0x1f) << ", main " << int(main_status_) << "; ");
// for(std::size_t c = 0; c < result_stack_.size(); c++) {
// LOGNBR(" " << 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;

4
Components/8272/i8272.hpp
View File

@ -9,6 +9,8 @@
#ifndef i8272_hpp
#define i8272_hpp
#include "CommandDecoder.hpp"
#include "../../Storage/Disk/Controller/MFMDiskController.hpp"
#include <cstdint>
@ -54,7 +56,7 @@ class i8272 : public Storage::Disk::MFMController {
uint8_t status_[3] = {0, 0, 0};
// A buffer for accumulating the incoming command, and one for accumulating the result.
std::vector<uint8_t> command_;
CommandDecoder command_;
std::vector<uint8_t> result_stack_;
uint8_t input_ = 0;
bool has_input_ = false;

2
OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
View File

@ -1146,6 +1146,7 @@
4267A9C82B0D4EC2008A59BB /* PIC.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = PIC.hpp; sourceTree = "<group>"; };
4267A9C92B0D4F17008A59BB /* DMA.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = DMA.hpp; sourceTree = "<group>"; };
4267A9CA2B111ED2008A59BB /* KeyboardMapper.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = KeyboardMapper.hpp; sourceTree = "<group>"; };
4267A9CB2B113958008A59BB /* CommandDecoder.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = CommandDecoder.hpp; sourceTree = "<group>"; };
4281572E2AA0334300E16AA1 /* Carry.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Carry.hpp; sourceTree = "<group>"; };
428168372A16C25C008ECD27 /* LineLayout.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = LineLayout.hpp; sourceTree = "<group>"; };
428168392A37AFB4008ECD27 /* DispatcherTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = DispatcherTests.mm; sourceTree = "<group>"; };
@ -4552,6 +4553,7 @@
children = (
4BBC951C1F368D83008F4C34 /* i8272.cpp */,
4BBC951D1F368D83008F4C34 /* i8272.hpp */,
4267A9CB2B113958008A59BB /* CommandDecoder.hpp */,
);
path = 8272;
sourceTree = "<group>";