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115 lines
2.8 KiB
C++
115 lines
2.8 KiB
C++
//
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// MFM.hpp
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// Clock Signal
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//
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// Created by Thomas Harte on 18/09/2016.
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// Copyright © 2016 Thomas Harte. All rights reserved.
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//
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#ifndef Storage_Disk_Encodings_MFM_hpp
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#define Storage_Disk_Encodings_MFM_hpp
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#include <cstdint>
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namespace Storage {
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namespace Encodings {
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template <class T> class Shifter {
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public:
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virtual void add_byte(uint8_t input) = 0;
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virtual void add_index_address_mark() = 0;
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virtual void add_ID_address_mark() = 0;
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virtual void add_data_address_mark() = 0;
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virtual void add_deleted_data_address_mark() = 0;
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protected:
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// override me!
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void output_short(uint16_t value);
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};
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template <class T> class MFMShifter: public Shifter<T> {
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public:
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void add_byte(uint8_t input) {
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uint16_t spread_value =
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(uint16_t)(
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((input & 0x01) << 0) |
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((input & 0x02) << 1) |
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((input & 0x04) << 2) |
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((input & 0x08) << 3) |
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((input & 0x10) << 4) |
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((input & 0x20) << 5) |
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((input & 0x40) << 6) |
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((input & 0x80) << 7)
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);
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uint16_t or_bits = (uint16_t)((spread_value << 1) | (spread_value >> 1) | (output_ << 15));
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output_ = spread_value | ((~or_bits) & 0xaaaa);
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static_cast<T *>(this)->output_short(output_);
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}
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void add_index_address_mark() {
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static_cast<T *>(this)->output_short(output_ = 0x5224);
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add_byte(0xfc);
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}
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void add_ID_address_mark() {
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static_cast<T *>(this)->output_short(output_ = 0x4489);
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add_byte(0xfe);
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}
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void add_data_address_mark() {
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static_cast<T *>(this)->output_short(output_ = 0x4489);
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add_byte(0xfb);
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}
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void add_deleted_data_address_mark() {
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static_cast<T *>(this)->output_short(output_ = 0x4489);
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add_byte(0xf8);
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}
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private:
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uint16_t output_;
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};
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template <class T> class FMShifter: public Shifter<T> {
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public:
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void add_byte(uint8_t input) {
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static_cast<T *>(this)->output_short(
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(uint16_t)(
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((input & 0x01) << 1) |
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((input & 0x02) << 2) |
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((input & 0x04) << 3) |
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((input & 0x08) << 4) |
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((input & 0x10) << 5) |
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((input & 0x20) << 6) |
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((input & 0x40) << 7) |
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((input & 0x80) << 8) |
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0x5555
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));
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}
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void add_index_address_mark() {
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// data 0xfc, with clock 0xd7 => 1111 1100 with clock 1101 0111 => 1111 1011 1011 0101
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static_cast<T *>(this)->output_short(0xfbb5);
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}
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void add_ID_address_mark() {
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// data 0xfe, with clock 0xc7 => 1111 1110 with clock 1100 0111 => 1111 1010 1011 1101
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static_cast<T *>(this)->output_short(0xfabd);
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}
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void add_data_address_mark() {
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// data 0xfb, with clock 0xc7 => 1111 1011 with clock 1100 0111 => 1111 1010 1001 1111
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static_cast<T *>(this)->output_short(0xfa9f);
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}
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void add_deleted_data_address_mark() {
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// data 0xf8, with clock 0xc7 => 1111 1000 with clock 1100 0111 => 1111 1010 1001 0101
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static_cast<T *>(this)->output_short(0xfa95);
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}
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};
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}
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}
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#endif /* MFM_hpp */
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