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formats/h8_cas.cpp: Update H8T to newer cassette handling (#13250)
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‎src/lib/formats/h8_cas.cpp

+50-109
Original file line numberDiff line numberDiff line change
@@ -1,8 +1,8 @@
11
// license:BSD-3-Clause
2-
// copyright-holders:Robbbert
2+
// copyright-holders:Robbbert,Mark Garlanger
33
/********************************************************************
44
5-
Support for Heathkit H8 H8T cassette images
5+
Support for Heathkit H8/H88 H8T cassette images
66
77
88
Standard Kansas City format (300 baud)
@@ -15,138 +15,79 @@ We output a leader, followed by the contents of the H8T file.
1515

1616
#include "h8_cas.h"
1717

18-
#include <algorithm>
18+
#include "coretmpl.h" // BIT
1919

2020

21-
static constexpr uint16_t WAVEENTRY_LOW = -32768;
22-
static constexpr uint16_t WAVEENTRY_HIGH = 32767;
23-
static constexpr uint16_t SILENCE = 0;
21+
namespace {
2422

25-
// using a multiple of 4800 will ensure an integer multiple of samples for each wave.
26-
static constexpr uint16_t H8_WAV_FREQUENCY = 9600;
27-
static constexpr uint16_t TAPE_BAUD_RATE = 300;
28-
static constexpr uint16_t SAMPLES_PER_BIT = H8_WAV_FREQUENCY / TAPE_BAUD_RATE;
29-
static constexpr uint16_t SAMPLES_PER_HALF_WAVE = SAMPLES_PER_BIT / 2;
23+
static constexpr double ONE_FREQ = 1200.0;
24+
static constexpr double ONE_FREQ_VARIANCE = 300.0;
25+
static constexpr double ZERO_FREQ = 2400.0;
26+
static constexpr double ZERO_FREQ_VARIANCE = 600.0;
3027

31-
static constexpr uint16_t ONE_FREQ = 1200;
32-
static constexpr uint16_t ZERO_FREQ = 2400;
33-
static constexpr uint16_t ONE_CYCLES = H8_WAV_FREQUENCY / ONE_FREQ;
34-
static constexpr uint16_t ZERO_CYCLES = H8_WAV_FREQUENCY / ZERO_FREQ;
35-
36-
// image size
37-
static int h8_image_size; // FIXME: global variable prevents multiple instances
38-
39-
static int h8_put_samples(int16_t *buffer, int sample_pos, int count, int level)
28+
static const cassette_image::Modulation heath_h8t_modulation =
4029
{
41-
if (buffer)
42-
{
43-
std::fill_n(&buffer[sample_pos], count, level);
44-
}
45-
46-
return count;
47-
}
30+
cassette_image::MODULATION_SINEWAVE,
31+
ONE_FREQ - ONE_FREQ_VARIANCE, ONE_FREQ, ONE_FREQ + ONE_FREQ_VARIANCE,
32+
ZERO_FREQ - ZERO_FREQ_VARIANCE, ZERO_FREQ, ZERO_FREQ + ZERO_FREQ_VARIANCE
33+
};
4834

49-
static int h8_output_bit(int16_t *buffer, int sample_pos, bool bit)
35+
static cassette_image::error heath_h8t_identify(cassette_image *cassette, cassette_image::Options *opts)
5036
{
51-
int samples = 0;
52-
53-
const int loops = bit ? ONE_CYCLES : ZERO_CYCLES;
54-
const int samplePerValue = SAMPLES_PER_HALF_WAVE / loops;
55-
56-
for (int i = 0; i < loops; i++)
57-
{
58-
samples += h8_put_samples(buffer, sample_pos + samples, samplePerValue, WAVEENTRY_LOW);
59-
samples += h8_put_samples(buffer, sample_pos + samples, samplePerValue, WAVEENTRY_HIGH);
60-
}
61-
62-
return samples;
37+
return cassette->modulation_identify(heath_h8t_modulation, opts);
6338
}
6439

65-
static int h8_output_byte(int16_t *buffer, int sample_pos, uint8_t data)
66-
{
67-
int samples = 0;
68-
69-
// start bit
70-
samples += h8_output_bit(buffer, sample_pos + samples, 0);
7140

72-
// data bits
73-
for (int i = 0; i < 8; i++)
74-
{
75-
samples += h8_output_bit(buffer, sample_pos + samples, data & 1);
76-
data >>= 1;
41+
#define MODULATE(_value) \
42+
for (int i = 0; i < (_value ? 8 : 4); i++) { \
43+
err = cassette->put_modulated_data_bit(0, time_index, _value, heath_h8t_modulation, &time_displacement); \
44+
if (err != cassette_image::error::SUCCESS) return err; \
45+
time_index += time_displacement; \
7746
}
7847

79-
// stop bit
80-
samples += h8_output_bit(buffer, sample_pos + samples, 1);
81-
82-
return samples;
83-
}
84-
85-
static int h8_handle_cassette(int16_t *buffer, const uint8_t *bytes)
48+
static cassette_image::error heath_h8t_load(cassette_image *cassette)
8649
{
87-
int sample_count = 0;
50+
cassette_image::error err = cassette_image::error::SUCCESS;
51+
uint64_t image_size = cassette->image_size();
52+
double time_index = 0.0;
53+
double time_displacement;
8854

8955
// leader - 1 second
90-
for (int i = 0; i < TAPE_BAUD_RATE; i++)
91-
sample_count += h8_output_bit(buffer, sample_count, 1);
92-
93-
// data
94-
for (int i = 0; i < h8_image_size; i++)
95-
sample_count += h8_output_byte(buffer, sample_count, bytes[i]);
96-
97-
return sample_count;
98-
}
99-
100-
101-
/*******************************************************************
102-
Generate samples for the tape image
103-
********************************************************************/
104-
105-
static int h8_cassette_fill_wave(int16_t *buffer, int length, const uint8_t *bytes)
106-
{
107-
return h8_handle_cassette(buffer, bytes);
108-
}
109-
110-
/*******************************************************************
111-
Calculate the number of samples needed for this tape image
112-
********************************************************************/
56+
while (time_index < 1.0)
57+
{
58+
MODULATE(1);
59+
}
11360

114-
static int h8_cassette_calculate_size_in_samples(const uint8_t *bytes, int length)
115-
{
116-
h8_image_size = length;
61+
for (uint64_t image_pos = 0; image_pos < image_size; image_pos++)
62+
{
63+
uint8_t data = cassette->image_read_byte(image_pos);
11764

118-
return h8_handle_cassette(nullptr, bytes);
119-
}
65+
// start bit
66+
MODULATE(0);
12067

121-
static const cassette_image::LegacyWaveFiller h8_legacy_fill_wave =
122-
{
123-
h8_cassette_fill_wave, // fill_wave
124-
-1, // chunk_size
125-
0, // chunk_samples
126-
h8_cassette_calculate_size_in_samples, // chunk_sample_calc
127-
H8_WAV_FREQUENCY, // sample_frequency
128-
0, // header_samples
129-
0 // trailer_samples
130-
};
68+
// data bits
69+
for (int bit = 0; bit < 8; bit++)
70+
{
71+
MODULATE(util::BIT(data, bit));
72+
}
13173

132-
static cassette_image::error h8_cassette_identify(cassette_image *cassette, cassette_image::Options *opts)
133-
{
134-
return cassette->legacy_identify(opts, &h8_legacy_fill_wave);
135-
}
74+
// stop bit
75+
MODULATE(1);
76+
}
13677

137-
static cassette_image::error h8_cassette_load(cassette_image *cassette)
138-
{
139-
return cassette->legacy_construct(&h8_legacy_fill_wave);
78+
return err;
14079
}
14180

142-
static const cassette_image::Format h8_cassette_image_format =
81+
const cassette_image::Format heath_h8t_format =
14382
{
14483
"h8t",
145-
h8_cassette_identify,
146-
h8_cassette_load,
84+
heath_h8t_identify,
85+
heath_h8t_load,
14786
nullptr
14887
};
14988

150-
CASSETTE_FORMATLIST_START(h8_cassette_formats)
151-
CASSETTE_FORMAT(h8_cassette_image_format)
89+
}
90+
91+
CASSETTE_FORMATLIST_START( h8_cassette_formats )
92+
CASSETTE_FORMAT( heath_h8t_format )
15293
CASSETTE_FORMATLIST_END

‎src/lib/formats/h8_cas.h

+2-2
Original file line numberDiff line numberDiff line change
@@ -1,10 +1,10 @@
11
// license:BSD-3-Clause
2-
// copyright-holders:Robbbert
2+
// copyright-holders:Robbbert,Mark Garlanger
33
/*********************************************************************
44
55
h8_cas.h
66
7-
Format code for Heathkit H8 H8T cassette images
7+
Format code for Heathkit H8/H88 H8T cassette images
88
99
*********************************************************************/
1010
#ifndef MAME_FORMATS_H8_CAS_H

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