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author | 2015-11-08 12:56:12 +0100 | |
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committer | 2015-11-08 12:56:12 +0100 | |
commit | 7c19aac60e12d6f5ea301bdb34d7826a01e0b06f (patch) | |
tree | f310d86aa2c6bfc19d115307dedde4eb0cd52dad /src/lib/formats/phc25_cas.cpp | |
parent | a57b46ae933badd7441ce1644711dbb851e2b504 (diff) |
Rename *.c -> *.cpp in our source (nw)
Diffstat (limited to 'src/lib/formats/phc25_cas.cpp')
-rw-r--r-- | src/lib/formats/phc25_cas.cpp | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/src/lib/formats/phc25_cas.cpp b/src/lib/formats/phc25_cas.cpp new file mode 100644 index 00000000000..1253bd98a3a --- /dev/null +++ b/src/lib/formats/phc25_cas.cpp @@ -0,0 +1,181 @@ +// license:BSD-3-Clause +// copyright-holders:Robbbert +/******************************************************************** + +Support for Sanyo PHC25 cassette images + +phc images consist of 5 sections +1. 10 A5 bytes +2. 6 name of the program +3. The basic program file. Each line is delimited by null. This + section is terminated by 3 nulls (1 of them for the preceeding + line, the other 2 indicate the end). +4. The line numbers and pointers to them. It ends at the image size-1 +5. A 1-byte trailer of FF which we do not pass on + +Each byte after conversion becomes a start bit, bit 0,1,etc to 7, +then 4 stop bits. + +An actual tape consists of 6 sections +a. 2.656secs of silence +b. 4.862secs of high bits +c. The header which is parts 1 and 2 above +d. 0.652secs of high bits +e. The main program which is parts 3 and 4 above +f. 1.771secs of silence + +We don't emulate the full silence and high-bits periods, only just +enough to make it work. + +********************************************************************/ + +#include <assert.h> + +#include "phc25_cas.h" + +#define WAVEENTRY_LOW -32768 +#define WAVEENTRY_HIGH 32767 + +#define PHC25_WAV_FREQUENCY 9600 +#define PHC25_HEADER_BYTES 16 + +// image size +static int phc25_image_size; + +static int phc25_put_samples(INT16 *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 phc25_output_bit(INT16 *buffer, int sample_pos, bool bit) +{ + int samples = 0; + + if (bit) + { + samples += phc25_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW); + samples += phc25_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH); + samples += phc25_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW); + samples += phc25_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH); + } + else + { + samples += phc25_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_LOW); + samples += phc25_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_HIGH); + } + + return samples; +} + +static int phc25_output_byte(INT16 *buffer, int sample_pos, UINT8 byte) +{ + int samples = 0; + UINT8 i; + + /* start */ + samples += phc25_output_bit (buffer, sample_pos + samples, 0); + + /* data */ + for (i = 0; i<8; i++) + samples += phc25_output_bit (buffer, sample_pos + samples, (byte >> i) & 1); + + /* stop */ + for (i = 0; i<4; i++) + samples += phc25_output_bit (buffer, sample_pos + samples, 1); + + return samples; +} + +static int phc25_handle_cassette(INT16 *buffer, const UINT8 *bytes) +{ + UINT32 sample_count = 0; + UINT32 byte_count = 0; + UINT32 i; + + // silence +// sample_count += phc25_put_samples(buffer, 6640, 2, WAVEENTRY_HIGH); + + /* start */ +// for (i=0; i<12155; i++) + for (i=0; i<2155; i++) + sample_count += phc25_output_bit(buffer, sample_count, 1); + + /* header */ + for (int i=0; i<PHC25_HEADER_BYTES; i++) + sample_count += phc25_output_byte(buffer, sample_count, bytes[i]); + + byte_count = PHC25_HEADER_BYTES; + + /* pause */ + for (i=0; i<1630; i++) + sample_count += phc25_output_bit(buffer, sample_count, 1); + + /* data */ + for (i=byte_count; i<phc25_image_size-1; i++) + sample_count += phc25_output_byte(buffer, sample_count, bytes[i]); + + // silence + sample_count += phc25_put_samples(buffer, 1000, 2, WAVEENTRY_HIGH); + + return sample_count; +} + + +/******************************************************************* + Generate samples for the tape image +********************************************************************/ + +static int phc25_cassette_fill_wave(INT16 *buffer, int length, UINT8 *bytes) +{ + return phc25_handle_cassette(buffer, bytes); +} + +/******************************************************************* + Calculate the number of samples needed for this tape image +********************************************************************/ + +static int phc25_cassette_calculate_size_in_samples(const UINT8 *bytes, int length) +{ + phc25_image_size = length; + + return phc25_handle_cassette(NULL, bytes); +} + +static const struct CassetteLegacyWaveFiller phc25_legacy_fill_wave = +{ + phc25_cassette_fill_wave, /* fill_wave */ + -1, /* chunk_size */ + 0, /* chunk_samples */ + phc25_cassette_calculate_size_in_samples, /* chunk_sample_calc */ + PHC25_WAV_FREQUENCY, /* sample_frequency */ + 0, /* header_samples */ + 0 /* trailer_samples */ +}; + +static casserr_t phc25_cassette_identify(cassette_image *cassette, struct CassetteOptions *opts) +{ + return cassette_legacy_identify(cassette, opts, &phc25_legacy_fill_wave); +} + +static casserr_t phc25_cassette_load(cassette_image *cassette) +{ + return cassette_legacy_construct(cassette, &phc25_legacy_fill_wave); +} + +static const struct CassetteFormat phc25_cassette_image_format = +{ + "phc", + phc25_cassette_identify, + phc25_cassette_load, + NULL +}; + +CASSETTE_FORMATLIST_START(phc25_cassette_formats) + CASSETTE_FORMAT(phc25_cassette_image_format) +CASSETTE_FORMATLIST_END |