diff options
author | 2020-04-06 01:37:05 +1000 | |
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committer | 2020-04-06 01:37:05 +1000 | |
commit | b5e08ae5e83f3c58948e82b80fb9b349504a9ef7 (patch) | |
tree | a7558259468d2732ae270ec901c90a5186e2c16a /src/lib/formats/h8_cas.cpp | |
parent | f07357d52bd52e1f861bb6d03ec5ea4d8d94e453 (diff) |
H8: added support for H8T tapes.
Diffstat (limited to 'src/lib/formats/h8_cas.cpp')
-rw-r--r-- | src/lib/formats/h8_cas.cpp | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/src/lib/formats/h8_cas.cpp b/src/lib/formats/h8_cas.cpp new file mode 100644 index 00000000000..ec92a94b10f --- /dev/null +++ b/src/lib/formats/h8_cas.cpp @@ -0,0 +1,149 @@ +// license:BSD-3-Clause +// copyright-holders:Robbbert +/******************************************************************** + +Support for Heathkit H8 H8T cassette images + + +Standard Kansas City format (300 baud) + +We output a leader, followed by the contents of the H8T file. + +********************************************************************/ + +#include <cassert> + +#include "h8_cas.h" + +#define WAVEENTRY_LOW -32768 +#define WAVEENTRY_HIGH 32767 + +#define H8_WAV_FREQUENCY 9600 + +// image size +static int h8_image_size; + +static int h8_put_samples(int16_t *buffer, int sample_pos, int count, int level) +{ + if (buffer) + { + for (int i=0; i<count; i++) + buffer[sample_pos + i] = level; + } + + return count; +} + +static int h8_output_bit(int16_t *buffer, int sample_pos, bool bit) +{ + int samples = 0; + + for (uint8_t i = 0; i < 4; i++) + { + if (bit) + { + samples += h8_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW); + samples += h8_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH); + samples += h8_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW); + samples += h8_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH); + } + else + { + samples += h8_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_LOW); + samples += h8_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_HIGH); + } + } + + return samples; +} + +static int h8_output_byte(int16_t *buffer, int sample_pos, uint8_t byte) +{ + int samples = 0; + uint8_t i; + + // start bit + samples += h8_output_bit (buffer, sample_pos + samples, 0); + + // data bits + for (i = 0; i<8; i++) + samples += h8_output_bit (buffer, sample_pos + samples, (byte >> i) & 1); + + // stop bits + for (i = 0; i<2; i++) + samples += h8_output_bit (buffer, sample_pos + samples, 1); + + return samples; +} + +static int h8_handle_cassette(int16_t *buffer, const uint8_t *bytes) +{ + uint32_t sample_count = 0; + uint32_t byte_count = 0; + uint32_t i; + + + // leader + for (i=0; i<2000; i++) + sample_count += h8_output_bit(buffer, sample_count, 1); + + // data + for (i=byte_count; i<h8_image_size; i++) + sample_count += h8_output_byte(buffer, sample_count, bytes[i]); + + return sample_count; +} + + +/******************************************************************* + Generate samples for the tape image +********************************************************************/ + +static int h8_cassette_fill_wave(int16_t *buffer, int length, uint8_t *bytes) +{ + return h8_handle_cassette(buffer, bytes); +} + +/******************************************************************* + Calculate the number of samples needed for this tape image +********************************************************************/ + +static int h8_cassette_calculate_size_in_samples(const uint8_t *bytes, int length) +{ + h8_image_size = length; + + return h8_handle_cassette(nullptr, bytes); +} + +static const struct CassetteLegacyWaveFiller h8_legacy_fill_wave = +{ + h8_cassette_fill_wave, /* fill_wave */ + -1, /* chunk_size */ + 0, /* chunk_samples */ + h8_cassette_calculate_size_in_samples, /* chunk_sample_calc */ + H8_WAV_FREQUENCY, /* sample_frequency */ + 0, /* header_samples */ + 0 /* trailer_samples */ +}; + +static cassette_image::error h8_cassette_identify(cassette_image *cassette, struct CassetteOptions *opts) +{ + return cassette_legacy_identify(cassette, opts, &h8_legacy_fill_wave); +} + +static cassette_image::error h8_cassette_load(cassette_image *cassette) +{ + return cassette_legacy_construct(cassette, &h8_legacy_fill_wave); +} + +static const struct CassetteFormat h8_cassette_image_format = +{ + "h8t", + h8_cassette_identify, + h8_cassette_load, + nullptr +}; + +CASSETTE_FORMATLIST_START(h8_cassette_formats) + CASSETTE_FORMAT(h8_cassette_image_format) +CASSETTE_FORMATLIST_END |