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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/mbee_cas.cpp | |
parent | a57b46ae933badd7441ce1644711dbb851e2b504 (diff) |
Rename *.c -> *.cpp in our source (nw)
Diffstat (limited to 'src/lib/formats/mbee_cas.cpp')
-rw-r--r-- | src/lib/formats/mbee_cas.cpp | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/src/lib/formats/mbee_cas.cpp b/src/lib/formats/mbee_cas.cpp new file mode 100644 index 00000000000..fe0a2ffbc24 --- /dev/null +++ b/src/lib/formats/mbee_cas.cpp @@ -0,0 +1,261 @@ +// license:BSD-3-Clause +// copyright-holders:Robbbert +/******************************************************************** + +Support for Microbee cassette images + +Microbee tapes consist of 3 sections +1. A leader of 63 zeroes +2. A header which contains the program name and other info +3. The main program + +Each byte after conversion becomes a start bit, bit 0,1,etc to 7, +then 2 stop bits. + +At 1200 baud, a high = 2 cycles of 2400Hz and a low = 1 cycle of 1200Hz +At 300 baud, a high = 8 cycles of 2400Hz and a low = 4 cycles of 1200Hz + +The header bytes are arranged thus: +1 (SOH) 0x01 +6 File name +1 file type (M=machine language, B=Basic) +2 length +2 load address +2 exec address +1 tape speed (0 = 300 baud; other = 1200 baud) +1 auto-start (0 = no) +1 unassigned byte +1 CRC byte + +The header is always at 300 baud; the program will be at the +speed indicated by the speed byte. + +By coincidence (or not), the header is the same format as that +of the Sorcerer and SOL-20. In these, the speed and auto-start +bytes are unassigned. The CRC uses the same algorithm. + +The main program is broken into blocks of 256, with each block +having its own CRC byte. + +Microbee tape and quickload formats: + +BEE - straight binary dump to address 0900, no header. For Machine + Language programs. + +BIN - the standard z80bin format. + +COM - straight binary dump to address 0100, no header. For Machine + Language programs. + +MWB - straight binary dump to address 08C0, no header. For BASIC + programs. + +TAP - has an ID header of TAP_DGOS_BEE or MBEE, null terminated. + This is followed by the binary dump with the leader and CRC + bytes included. + +********************************************************************/ + +#include <assert.h> + +#include "mbee_cas.h" + +#define WAVEENTRY_LOW -32768 +#define WAVEENTRY_HIGH 32767 + +#define MBEE_WAV_FREQUENCY 9600 + +// image size +static int mbee_image_size; +static bool mbee_speed; + +static int mbee_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 mbee_output_bit(INT16 *buffer, int sample_pos, bool bit) +{ + int samples = 0; + if (mbee_speed) + { + if (bit) + { + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH); + } + else + { + samples += mbee_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_LOW); + samples += mbee_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_HIGH); + } + } + else + { + if (bit) + { + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_LOW); + samples += mbee_put_samples(buffer, sample_pos + samples, 2, WAVEENTRY_HIGH); + } + else + { + samples += mbee_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_LOW); + samples += mbee_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_HIGH); + samples += mbee_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_LOW); + samples += mbee_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_HIGH); + samples += mbee_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_LOW); + samples += mbee_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_HIGH); + samples += mbee_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_LOW); + samples += mbee_put_samples(buffer, sample_pos + samples, 4, WAVEENTRY_HIGH); + } + } + + return samples; +} + +static int mbee_output_byte(INT16 *buffer, int sample_pos, UINT8 byte) +{ + int samples = 0; + UINT8 i; + + /* start */ + samples += mbee_output_bit (buffer, sample_pos + samples, 0); + + /* data */ + for (i = 0; i<8; i++) + samples += mbee_output_bit (buffer, sample_pos + samples, (byte >> i) & 1); + + /* stop */ + for (i = 0; i<2; i++) + samples += mbee_output_bit (buffer, sample_pos + samples, 1); + + return samples; +} + +static int mbee_handle_tap(INT16 *buffer, const UINT8 *bytes) +{ + UINT32 sample_count = 0; + UINT32 byte_count = 0; + UINT32 i = 0; + bool temp_speed = 0; + UINT8 temp_blocks = 0; + UINT16 temp_size = 0; + + // TAP file starts with a null-terminate ID string. We just skip this. + while (bytes[byte_count]) + byte_count++; + + // there can be a library of files, loop through them all + while (byte_count < mbee_image_size) + { + mbee_speed = 0; + + // now output the leader + while ( (!bytes[byte_count]) && (byte_count < mbee_image_size) ) + sample_count += mbee_output_byte(buffer, sample_count, bytes[byte_count++]); + + // make sure SOH is where we expect + if (bytes[byte_count] != 1 ) + break; + + // store the size for later + temp_blocks = bytes[byte_count + 9]; + temp_size = bytes[byte_count + 8] + temp_blocks*256; + + // store the speed for later + temp_speed = (bytes[byte_count + 15]) ? 1 : 0; + + /* header */ + for (i=0; i<18; i++) + sample_count += mbee_output_byte(buffer, sample_count, bytes[byte_count++]); + + // change speed + mbee_speed = temp_speed; + + // calculate size of program including CRC bytes + temp_size = temp_size + temp_blocks + 1; + + /* data */ + for (i=0; i<temp_size; i++) + sample_count += mbee_output_byte(buffer, sample_count, bytes[byte_count++]); + + } + + return sample_count; +} + + +/******************************************************************* + Generate samples for the tape image +********************************************************************/ + +static int mbee_tap_fill_wave(INT16 *buffer, int length, UINT8 *bytes) +{ + return mbee_handle_tap(buffer, bytes); +} + +/******************************************************************* + Calculate the number of samples needed for this tape image +********************************************************************/ + +static int mbee_tap_calculate_size_in_samples(const UINT8 *bytes, int length) +{ + mbee_image_size = length; + + return mbee_handle_tap(NULL, bytes); +} + +static const struct CassetteLegacyWaveFiller mbee_tap_config = +{ + mbee_tap_fill_wave, /* fill_wave */ + -1, /* chunk_size */ + 0, /* chunk_samples */ + mbee_tap_calculate_size_in_samples, /* chunk_sample_calc */ + MBEE_WAV_FREQUENCY, /* sample_frequency */ + 0, /* header_samples */ + 0 /* trailer_samples */ +}; + +static casserr_t mbee_tap_identify(cassette_image *cassette, struct CassetteOptions *opts) +{ + return cassette_legacy_identify(cassette, opts, &mbee_tap_config); +} + +static casserr_t mbee_tap_load(cassette_image *cassette) +{ + return cassette_legacy_construct(cassette, &mbee_tap_config); +} + +static const struct CassetteFormat mbee_tap_image_format = +{ + "tap", + mbee_tap_identify, + mbee_tap_load, + NULL +}; + +CASSETTE_FORMATLIST_START(mbee_cassette_formats) + CASSETTE_FORMAT(mbee_tap_image_format) +CASSETTE_FORMATLIST_END |