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// license:BSD-3-Clause
// copyright-holders:Curt Coder
/*********************************************************************
formats/sc3000_bit.c
Cassette code for Sega SC-3000 *.bit files
*********************************************************************/
#include <cassert>
#include "sc3000_bit.h"
/***************************************************************************
PARAMETERS
***************************************************************************/
#define LOG 0
/***************************************************************************
IMPLEMENTATION
***************************************************************************/
/*-------------------------------------------------
CassetteModulation sc3000_bit_modulation
-------------------------------------------------*/
static const struct CassetteModulation sc3000_bit_modulation =
{
CASSETTE_MODULATION_SINEWAVE,
1200.0 - 300, 1200.0, 1200.0 + 300,
2400.0 - 600, 2400.0, 2400.0 + 600
};
/*-------------------------------------------------
sc3000_bit_identify - identify cassette
-------------------------------------------------*/
static cassette_image::error sc3000_bit_identify(cassette_image *cassette, struct CassetteOptions *opts)
{
return cassette_modulation_identify( cassette, &sc3000_bit_modulation, opts);
}
/*-------------------------------------------------
sc3000_bit_load - load cassette
-------------------------------------------------*/
#define MODULATE(_value) \
for (int i = 0; i < (_value ? 2 : 1); i++) { \
err = cassette_put_modulated_data_bit(cassette, 0, time_index, _value, &sc3000_bit_modulation, &time_displacement);\
if (err != cassette_image::error::SUCCESS) return err;\
time_index += time_displacement;\
}
static cassette_image::error sc3000_bit_load(cassette_image *cassette)
{
cassette_image::error err;
uint64_t image_size = cassette_image_size(cassette);
uint64_t image_pos = 0;
double time_index = 0.0;
double time_displacement;
uint8_t data;
while (image_pos < image_size)
{
cassette_image_read(cassette, &data, image_pos, 1);
switch (data)
{
case '1':
MODULATE(1);
break;
case '0':
MODULATE(0);
break;
case ' ':
err = cassette_put_sample( cassette, 0, time_index, 1/1200.0, 0);
if (err != cassette_image::error::SUCCESS) return err;
time_index += 1/1200.0;
break;
}
image_pos++;
}
return cassette_image::error::SUCCESS;
}
/*-------------------------------------------------
CassetteFormat sc3000_bit_cassette_format
-------------------------------------------------*/
const struct CassetteFormat sc3000_bit_format =
{
"bit",
sc3000_bit_identify,
sc3000_bit_load,
nullptr
};
CASSETTE_FORMATLIST_START( sc3000_cassette_formats )
CASSETTE_FORMAT(sc3000_bit_format)
CASSETTE_FORMATLIST_END
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