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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/trs_cas.cpp | |
parent | a57b46ae933badd7441ce1644711dbb851e2b504 (diff) |
Rename *.c -> *.cpp in our source (nw)
Diffstat (limited to 'src/lib/formats/trs_cas.cpp')
-rw-r--r-- | src/lib/formats/trs_cas.cpp | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/src/lib/formats/trs_cas.cpp b/src/lib/formats/trs_cas.cpp new file mode 100644 index 00000000000..a4f748dea05 --- /dev/null +++ b/src/lib/formats/trs_cas.cpp @@ -0,0 +1,137 @@ +// license:BSD-3-Clause +// copyright-holders:Wilbert Pol +/******************************************************************** + +Support for TRS80 .cas cassette images + +********************************************************************/ + +#include <assert.h> + +#include "formats/trs_cas.h" + +#define SILENCE 0 +#define SMPLO -32768 +#define SMPHI 32767 + + +static int cas_size; + + +/******************************************************************* + Generate one high-low cycle of sample data +********************************************************************/ +INLINE int trs80l2_cas_cycle(INT16 *buffer, int sample_pos, int silence, int high, int low) +{ + int i = 0; + + if ( buffer ) + { + while( i < silence ) + { + buffer[ sample_pos + i ] = SILENCE; + i++; + } + while( i < silence + high) + { + buffer[ sample_pos + i ] = SMPHI; + i++; + } + + while( i < silence + high + low ) + { + buffer[ sample_pos + i ] = SMPLO; + i++; + } + } + return silence + high + low; +} + + +static int trs80l2_handle_cas(INT16 *buffer, const UINT8 *casdata) +{ + int data_pos, sample_count; + + data_pos = 0; + sample_count = 0; + + while( data_pos < cas_size ) + { + UINT8 data = casdata[data_pos]; + int i; + + for ( i = 0; i < 8; i++ ) + { + /* Signal code */ + sample_count += trs80l2_cas_cycle( buffer, sample_count, 33, 6, 6 ); + + /* Bit code */ + if ( data & 0x80 ) + sample_count += trs80l2_cas_cycle( buffer, sample_count, 33, 6, 6 ); + else + sample_count += trs80l2_cas_cycle( buffer, sample_count, 33 + 6 + 6, 0, 0 ); + + data <<= 1; + } + + data_pos++; + } + return sample_count; +} + + +/******************************************************************* + Generate samples for the tape image +********************************************************************/ +static int trs80l2_cas_fill_wave(INT16 *buffer, int sample_count, UINT8 *bytes) +{ + return trs80l2_handle_cas( buffer, bytes ); +} + + +/******************************************************************* + Calculate the number of samples needed for this tape image +********************************************************************/ +static int trs80l2_cas_to_wav_size(const UINT8 *casdata, int caslen) +{ + cas_size = caslen; + + return trs80l2_handle_cas( NULL, casdata ); +} + +static const struct CassetteLegacyWaveFiller trs80l2_cas_legacy_fill_wave = +{ + trs80l2_cas_fill_wave, /* fill_wave */ + -1, /* chunk_size */ + 0, /* chunk_samples */ + trs80l2_cas_to_wav_size, /* chunk_sample_calc */ + 44100, /* sample_frequency */ + 0, /* header_samples */ + 0 /* trailer_samples */ +}; + + +static casserr_t trs80l2_cas_identify(cassette_image *cassette, struct CassetteOptions *opts) +{ + return cassette_legacy_identify(cassette, opts, &trs80l2_cas_legacy_fill_wave); +} + + +static casserr_t trs80l2_cas_load(cassette_image *cassette) +{ + return cassette_legacy_construct(cassette, &trs80l2_cas_legacy_fill_wave); +} + + +static const struct CassetteFormat trs80l2_cas_format = +{ + "cas", + trs80l2_cas_identify, + trs80l2_cas_load, + NULL +}; + + +CASSETTE_FORMATLIST_START(trs80l2_cassette_formats) + CASSETTE_FORMAT(trs80l2_cas_format) +CASSETTE_FORMATLIST_END |