// license:BSD-3-Clause // copyright-holders:Robbbert,Nigel Barnes /******************************************************************** Support for Camputers Lynx cassette images We support TAP files used by the Pale and Jynx emulators. Tape format: - about 7 seconds of zeroes - A5 byte - 22 byte - program name - 22 byte - about 7 seconds of zeroes - A5 byte - header - main program - checksum Each byte is 8 bits (MSB first) with no start or stop bits. ********************************************************************/ #include "emu.h" // for popmessage and #include "camplynx_cas.h" #define WAVEENTRY_LOW -32768 #define WAVEENTRY_HIGH 32767 #define LYNX48K_WAV_FREQUENCY 4000 #define LYNX128K_WAV_FREQUENCY 8000 // image size static int camplynx_image_size; static int camplynx_put_samples(int16_t *buffer, int sample_pos, int count, int level) { if (buffer) { for (int i=0; i> (7-i)) & 1); return samples; } static int camplynx_handle_cassette(int16_t *buffer, const uint8_t *bytes) { uint32_t sample_count = 0; uint32_t byte_count = 0; uint32_t data_size = 0; uint32_t i; uint8_t file_type; std::string pgmname = ""; while (byte_count < camplynx_image_size) { /* initial SYNC + A5 applies to all file types */ for (i = 0; i < 555; i++) sample_count += camplynx_output_byte(buffer, sample_count, 0); sample_count += camplynx_output_byte(buffer, sample_count, 0xA5); /* some TAPs have a spurious A5 at the start, ignore */ while (bytes[byte_count] == 0xA5) byte_count++; if (bytes[byte_count] == 0x22) { pgmname = " LOAD \""; byte_count++; sample_count += camplynx_output_byte(buffer, sample_count, 0x22); /* output program name - include protection in case tape is corrupt */ for (i = byte_count; bytes[i] != 0x22; i++) { if (i < camplynx_image_size) { sample_count += camplynx_output_byte(buffer, sample_count, bytes[i]); pgmname.append(1, (char)bytes[i]); } else return sample_count; byte_count++; } pgmname.append(1, (char)0x22); sample_count += camplynx_output_byte(buffer, sample_count, bytes[byte_count++]); // should be 0x22 /* read file type letter, should be 'B' or 'M' */ file_type = bytes[byte_count]; /* if a machine-language program, say to use MLOAD */ if (file_type == 'M') pgmname[0] = 'M'; /* tell user how to load the tape */ if (buffer) osd_printf_info("%s\n", pgmname); /* second SYNC + A5 */ for (i = 0; i < 555; i++) sample_count += camplynx_output_byte(buffer, sample_count, 0); sample_count += camplynx_output_byte(buffer, sample_count, 0xA5); } /* read file type letter, should be 'A', 'B' or 'M' */ file_type = bytes[byte_count]; /* determine the data size (as recorded in the file) + extra bytes per file type */ switch (file_type) { case 'A': data_size = 5 + ((bytes[byte_count + 4]) << 8 | bytes[byte_count + 3]) + 12; break; case 'B': data_size = 3 + ((bytes[byte_count + 2]) << 8 | bytes[byte_count + 1]) + 3; break; case 'M': data_size = 3 + ((bytes[byte_count + 2]) << 8 | bytes[byte_count + 1]) + 7; break; } /* output data - include protection in case tape is corrupt */ for (i = byte_count; i < byte_count + data_size; i++) { if (i < camplynx_image_size) { sample_count += camplynx_output_byte(buffer, sample_count, bytes[i]); } } byte_count += data_size; /* some TAPs have a spurious 00 at the end, ignore */ while (bytes[byte_count] == 0x00) byte_count++; } return sample_count; } /******************************************************************* Generate samples for the tape image ********************************************************************/ static int camplynx_cassette_fill_wave(int16_t *buffer, int length, uint8_t *bytes) { return camplynx_handle_cassette(buffer, bytes); } /******************************************************************* Calculate the number of samples needed for this tape image ********************************************************************/ static int camplynx_cassette_calculate_size_in_samples(const uint8_t *bytes, int length) { camplynx_image_size = length; return camplynx_handle_cassette(nullptr, bytes); } static const struct CassetteLegacyWaveFiller lynx48k_legacy_fill_wave = { camplynx_cassette_fill_wave, /* fill_wave */ -1, /* chunk_size */ 0, /* chunk_samples */ camplynx_cassette_calculate_size_in_samples, /* chunk_sample_calc */ LYNX48K_WAV_FREQUENCY, /* sample_frequency */ 0, /* header_samples */ 0 /* trailer_samples */ }; static const struct CassetteLegacyWaveFiller lynx128k_legacy_fill_wave = { camplynx_cassette_fill_wave, /* fill_wave */ -1, /* chunk_size */ 0, /* chunk_samples */ camplynx_cassette_calculate_size_in_samples, /* chunk_sample_calc */ LYNX128K_WAV_FREQUENCY, /* sample_frequency */ 0, /* header_samples */ 0 /* trailer_samples */ }; static cassette_image::error lynx48k_cassette_identify(cassette_image *cassette, struct CassetteOptions *opts) { return cassette_legacy_identify(cassette, opts, &lynx48k_legacy_fill_wave); } static cassette_image::error lynx128k_cassette_identify(cassette_image *cassette, struct CassetteOptions *opts) { return cassette_legacy_identify(cassette, opts, &lynx128k_legacy_fill_wave); } static cassette_image::error lynx48k_cassette_load(cassette_image *cassette) { return cassette_legacy_construct(cassette, &lynx48k_legacy_fill_wave); } static cassette_image::error lynx128k_cassette_load(cassette_image *cassette) { return cassette_legacy_construct(cassette, &lynx128k_legacy_fill_wave); } static const struct CassetteFormat lynx48k_cassette_image_format = { "tap", lynx48k_cassette_identify, lynx48k_cassette_load, nullptr }; static const struct CassetteFormat lynx128k_cassette_image_format = { "tap", lynx128k_cassette_identify, lynx128k_cassette_load, nullptr }; CASSETTE_FORMATLIST_START(lynx48k_cassette_formats) CASSETTE_FORMAT(lynx48k_cassette_image_format) CASSETTE_FORMATLIST_END CASSETTE_FORMATLIST_START(lynx128k_cassette_formats) CASSETTE_FORMAT(lynx128k_cassette_image_format) CASSETTE_FORMATLIST_END