// license:BSD-3-Clause // copyright-holders:F. Ulivi /********************************************************************* "HTI" format Format of images of DC-100 tape cassettes as used in HP 9825, HP 9845 and HP 85 systems. *********************************************************************/ #ifndef MAME_FORMATS_HTI_TAPE_H #define MAME_FORMATS_HTI_TAPE_H #pragma once #include "ioprocs.h" #include class hti_format_t { public: hti_format_t(); // Tape position, 1 unit = 1 inch / (968 * 1024) typedef int32_t tape_pos_t; // 1 inch in tape_pos_t static constexpr tape_pos_t ONE_INCH_POS = 968 * 1024; // Special value for invalid/unknown tape position static constexpr tape_pos_t NULL_TAPE_POS = -1; // Tape length: 140 ft of usable tape + 72" of punched tape at either end static constexpr tape_pos_t TAPE_LENGTH = (140 * 12 + 72 * 2) * ONE_INCH_POS; // Length of 0 bits at slow tape speed: 1/(35200 Hz) static constexpr tape_pos_t ZERO_BIT_LEN = 619; // Length of 1 bits at slow tape speed: 1.75 times ZERO_BIT_LEN static constexpr tape_pos_t ONE_BIT_LEN = 1083; // Words stored on tape typedef uint16_t tape_word_t; // Storage of tracks: mapping from a tape position to word stored there typedef std::map tape_track_t; // Iterator to access words on tape typedef tape_track_t::iterator track_iterator_t; // Set no. of bits per word (needed when loading old format) void set_bits_per_word(unsigned bits) { m_bits_per_word = bits; } bool load_tape(io_generic *io); void save_tape(io_generic *io); void clear_tape(); // Return physical length of a bit on tape static constexpr tape_pos_t bit_length(bool bit) { return bit ? ONE_BIT_LEN : ZERO_BIT_LEN; } // Return physical length of a 16-bit word on tape static tape_pos_t word_length(tape_word_t w); static tape_pos_t farthest_end(const track_iterator_t& it , bool forward); static bool pos_offset(tape_pos_t& pos , bool forward , tape_pos_t offset); // Position of next hole tape will reach in a given direction static tape_pos_t next_hole(tape_pos_t pos , bool forward); // Write a data word on tape void write_word(unsigned track_no , tape_pos_t start , tape_word_t word , tape_pos_t& length , bool forward = true); // Write a gap on tape void write_gap(unsigned track_no , tape_pos_t a , tape_pos_t b); // Check that a section of tape has no data (it's just gap) bool just_gap(unsigned track_no , tape_pos_t a , tape_pos_t b); // Return position of next data word in a given direction bool next_data(unsigned track_no , tape_pos_t pos , bool forward , bool inclusive , track_iterator_t& it); enum adv_res_t { ADV_NO_MORE_DATA, ADV_CONT_DATA, ADV_DISCONT_DATA }; // Advance an iterator to next word of data adv_res_t adv_it(unsigned track_no , bool forward , track_iterator_t& it); // Sync with the preamble of a record bool sync_with_record(unsigned track_no , track_iterator_t& it , unsigned& bit_idx); // Get a data word from record, after syncing adv_res_t next_word(unsigned track_no , track_iterator_t& it , unsigned& bit_idx , tape_word_t& word); // Scan for beginning of next gap in a given direction bool next_gap(unsigned track_no , tape_pos_t& pos , bool forward , tape_pos_t min_gap); private: // Content of tape tracks tape_track_t m_tracks[ 2 ]; // Bits per word in old format unsigned m_bits_per_word; bool load_track(io_generic *io , uint64_t& offset , tape_track_t& track , bool old_format); static void dump_sequence(io_generic *io , uint64_t& offset , tape_track_t::const_iterator it_start , unsigned n_words); static tape_pos_t word_end_pos(const track_iterator_t& it); static void adjust_it(tape_track_t& track , track_iterator_t& it , tape_pos_t pos); static void ensure_a_lt_b(tape_pos_t& a , tape_pos_t& b); }; #endif // MAME_FORMATS_HTI_TAPE_H