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Factors shifting plus stateful [M]FM token recognition out of the MFMDiskController.

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Given the proliferation of MFM-related classes, establishes a subdirectory for them.
This commit is contained in:
Thomas Harte
2017-09-24 20:07:56 -04:00
parent f789ee4ff0
commit 2a08bd9ecc
17 changed files with 287 additions and 142 deletions
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125
Storage/Disk/Controller/MFMDiskController.cpp
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@@ -8,7 +8,7 @@
#include "MFMDiskController.hpp"
#include "../Encodings/MFM.hpp"
#include "../Encodings/MFM/MFM.hpp"
using namespace Storage::Disk;
@@ -16,7 +16,7 @@ MFMController::MFMController(Cycles clock_rate) :
Storage::Disk::Controller(clock_rate),
crc_generator_(0x1021, 0xffff),
data_mode_(DataMode::Scanning),
is_awaiting_marker_value_(false) {
shifter_(&crc_generator_) {
}
void MFMController::process_index_hole() {
@@ -34,7 +34,7 @@ void MFMController::set_is_double_density(bool is_double_density) {
bit_length.clock_rate = is_double_density ? 500000 : 250000;
set_expected_bit_length(bit_length);
if(!is_double_density) is_awaiting_marker_value_ = false;
shifter_.set_is_double_density(is_double_density);
}
bool MFMController::get_is_double_density() {
@@ -43,6 +43,7 @@ bool MFMController::get_is_double_density() {
void MFMController::set_data_mode(DataMode mode) {
data_mode_ = mode;
shifter_.set_should_obey_syncs(mode == DataMode::Scanning);
}
MFMController::Token MFMController::get_latest_token() {
@@ -56,102 +57,32 @@ NumberTheory::CRC16 &MFMController::get_crc_generator() {
void MFMController::process_input_bit(int value) {
if(data_mode_ == DataMode::Writing) return;
shift_register_ = (shift_register_ << 1) | value;
bits_since_token_++;
if(data_mode_ == DataMode::Scanning) {
Token::Type token_type = Token::Byte;
if(!is_double_density_) {
switch(shift_register_ & 0xffff) {
case Storage::Encodings::MFM::FMIndexAddressMark:
token_type = Token::Index;
crc_generator_.reset();
crc_generator_.add(latest_token_.byte_value = Storage::Encodings::MFM::IndexAddressByte);
break;
case Storage::Encodings::MFM::FMIDAddressMark:
token_type = Token::ID;
crc_generator_.reset();
crc_generator_.add(latest_token_.byte_value = Storage::Encodings::MFM::IDAddressByte);
break;
case Storage::Encodings::MFM::FMDataAddressMark:
token_type = Token::Data;
crc_generator_.reset();
crc_generator_.add(latest_token_.byte_value = Storage::Encodings::MFM::DataAddressByte);
break;
case Storage::Encodings::MFM::FMDeletedDataAddressMark:
token_type = Token::DeletedData;
crc_generator_.reset();
crc_generator_.add(latest_token_.byte_value = Storage::Encodings::MFM::DeletedDataAddressByte);
break;
default:
break;
}
} else {
switch(shift_register_ & 0xffff) {
case Storage::Encodings::MFM::MFMIndexSync:
bits_since_token_ = 0;
is_awaiting_marker_value_ = true;
token_type = Token::Sync;
latest_token_.byte_value = Storage::Encodings::MFM::MFMIndexSyncByteValue;
break;
case Storage::Encodings::MFM::MFMSync:
bits_since_token_ = 0;
is_awaiting_marker_value_ = true;
crc_generator_.set_value(Storage::Encodings::MFM::MFMPostSyncCRCValue);
token_type = Token::Sync;
latest_token_.byte_value = Storage::Encodings::MFM::MFMSyncByteValue;
break;
default:
break;
}
}
if(token_type != Token::Byte) {
latest_token_.type = token_type;
bits_since_token_ = 0;
posit_event((int)Event::Token);
return;
}
}
if(bits_since_token_ == 16) {
latest_token_.type = Token::Byte;
latest_token_.byte_value = (uint8_t)(
((shift_register_ & 0x0001) >> 0) |
((shift_register_ & 0x0004) >> 1) |
((shift_register_ & 0x0010) >> 2) |
((shift_register_ & 0x0040) >> 3) |
((shift_register_ & 0x0100) >> 4) |
((shift_register_ & 0x0400) >> 5) |
((shift_register_ & 0x1000) >> 6) |
((shift_register_ & 0x4000) >> 7));
bits_since_token_ = 0;
if(is_awaiting_marker_value_ && is_double_density_) {
is_awaiting_marker_value_ = false;
switch(latest_token_.byte_value) {
case Storage::Encodings::MFM::IndexAddressByte:
latest_token_.type = Token::Index;
break;
case Storage::Encodings::MFM::IDAddressByte:
latest_token_.type = Token::ID;
break;
case Storage::Encodings::MFM::DataAddressByte:
latest_token_.type = Token::Data;
break;
case Storage::Encodings::MFM::DeletedDataAddressByte:
latest_token_.type = Token::DeletedData;
break;
default: break;
}
}
crc_generator_.add(latest_token_.byte_value);
posit_event((int)Event::Token);
shifter_.add_input_bit(value);
switch(shifter_.get_token()) {
case Encodings::MFM::Shifter::Token::None:
return;
case Encodings::MFM::Shifter::Token::Index:
latest_token_.type = Token::Index;
break;
case Encodings::MFM::Shifter::Token::ID:
latest_token_.type = Token::ID;
break;
case Encodings::MFM::Shifter::Token::Data:
latest_token_.type = Token::Data;
break;
case Encodings::MFM::Shifter::Token::DeletedData:
latest_token_.type = Token::DeletedData;
break;
case Encodings::MFM::Shifter::Token::Sync:
latest_token_.type = Token::Sync;
break;
case Encodings::MFM::Shifter::Token::Byte:
latest_token_.type = Token::Byte;
break;
}
latest_token_.byte_value = shifter_.get_byte();
posit_event((int)Event::Token);
}
void MFMController::write_bit(int bit) {