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-rw-r--r--src/lib/formats/tvc_cas.cpp229
1 files changed, 229 insertions, 0 deletions
diff --git a/src/lib/formats/tvc_cas.cpp b/src/lib/formats/tvc_cas.cpp
new file mode 100644
index 00000000000..a33fba687b9
--- /dev/null
+++ b/src/lib/formats/tvc_cas.cpp
@@ -0,0 +1,229 @@
+// license:BSD-3-Clause
+// copyright-holders:Sandro Ronco
+/********************************************************************
+
+ Support for Videoton TVC .cas files
+
+ http://tvc.homeserver.hu/html/konvertformatum.html
+
+********************************************************************/
+
+#include <assert.h>
+
+#include "tvc_cas.h"
+
+#define TVC64_BIT0_FREQ 1812
+#define TVC64_BIT1_FREQ 2577
+#define TVC64_PRE_FREQ 2128
+#define TVC64_SYNC_FREQ 1359
+
+#define WAVE_AMPLITUDE 0x3fffffff
+#define TVC64_HEADER_BYTES 0x90
+#define TVC64_HEADER_BYTES 0x90
+
+static void tvc64_emit_level(cassette_image *cass, double &time, int freq, int level)
+{
+ double period = 1.0 / freq;
+ cassette_put_sample(cass, 0, time, period, level * WAVE_AMPLITUDE);
+ time += period;
+}
+
+static casserr_t tvc64_output_byte(cassette_image *cass, double &time, UINT8 byte)
+{
+ for (int i=0; i<8; i++)
+ {
+ if ((byte>>i) & 0x01)
+ {
+ tvc64_emit_level(cass, time, TVC64_BIT1_FREQ*2, +1);
+ tvc64_emit_level(cass, time, TVC64_BIT1_FREQ*2, -1);
+ }
+ else
+ {
+ tvc64_emit_level(cass, time, TVC64_BIT0_FREQ*2, +1);
+ tvc64_emit_level(cass, time, TVC64_BIT0_FREQ*2, -1);
+ }
+ }
+
+ return CASSETTE_ERROR_SUCCESS;
+}
+
+static int tvc64_output_predata(cassette_image *cass, double &time, int number)
+{
+ for (int i=0; i<number; i++)
+ {
+ tvc64_emit_level(cass, time, TVC64_PRE_FREQ*2, +1);
+ tvc64_emit_level(cass, time, TVC64_PRE_FREQ*2, -1);
+ }
+
+ return CASSETTE_ERROR_SUCCESS;
+}
+
+static UINT16 tvc64_calc_crc(const UINT8 *bytes, int size)
+{
+ UINT16 crc = 0;
+
+ for (int i=0; i<size; i++)
+ {
+ for (int b=0; b<8; b++)
+ {
+ UINT8 al = (bytes[i] & (1<<b)) ? 0x80 : 0x00;
+
+ al ^= ((crc>>8) & 0xff);
+
+ if (al & 0x80)
+ crc ^= 0x0810;
+
+ crc <<= 1;
+
+ if (al & 0x80) crc += 1;
+ }
+ }
+
+ return crc;
+}
+
+static casserr_t tvc64_cassette_load(cassette_image *cassette)
+{
+ UINT8 tmp_buff[512];
+ int buff_idx = 0;
+ double time = 0.0;
+
+ UINT8 header[TVC64_HEADER_BYTES];
+ cassette_image_read(cassette, header, 0, TVC64_HEADER_BYTES);
+ UINT16 cas_size = (header[0x83]<<8) | header[0x82];
+
+ // tape header
+ tmp_buff[buff_idx++] = 0x00;
+ tmp_buff[buff_idx++] = 0x6a;
+ tmp_buff[buff_idx++] = 0xff; // head sector
+ tmp_buff[buff_idx++] = 0x11; // not puffered
+ tmp_buff[buff_idx++] = 0x00; // not write protected
+ tmp_buff[buff_idx++] = 0x01; // 1 sector
+ tmp_buff[buff_idx++] = 0x00; // sector number
+ tmp_buff[buff_idx++] = 0x12; // head size
+ tmp_buff[buff_idx++] = 0x01; // name size
+ tmp_buff[buff_idx++] = ' '; // name
+ tmp_buff[buff_idx++] = 0x00;
+ tmp_buff[buff_idx++] = header[0x81]; // type
+ tmp_buff[buff_idx++] = header[0x82]; // size LSB
+ tmp_buff[buff_idx++] = header[0x83]; // size MSB
+ tmp_buff[buff_idx++] = header[0x84]; // autostart
+
+ // sector fill
+ for (int i=0; i<10 ; i++)
+ tmp_buff[buff_idx++] = 0x00;
+
+ tmp_buff[buff_idx++] = 0x00; // file version
+ tmp_buff[buff_idx++] = 0x00; // no last sector
+
+ // updates the header CRC
+ UINT16 crc = tvc64_calc_crc(tmp_buff, buff_idx);
+ tmp_buff[buff_idx++] = crc & 0xff;
+ tmp_buff[buff_idx++] = (crc>>8) & 0xff;
+
+ // 2 sec silence
+ tvc64_emit_level(cassette, time, 2, 0);
+
+ // 10240 pre data cycles
+ tvc64_output_predata(cassette, time, 10240);
+
+ // 1 synchro cycle
+ tvc64_emit_level(cassette, time, TVC64_SYNC_FREQ*2, +1);
+ tvc64_emit_level(cassette, time, TVC64_SYNC_FREQ*2, -1);
+
+ // header data
+ for (int i=0; i<buff_idx; i++)
+ tvc64_output_byte(cassette, time, tmp_buff[i]);
+
+ // 5 post data cycles
+ tvc64_output_predata(cassette, time, 5);
+
+ // 1 sec silence
+ tvc64_emit_level(cassette, time, 1, 0);
+
+ // 5120 pre data cycles
+ tvc64_output_predata(cassette, time, 5120);
+
+ // 1 synchro cycle
+ tvc64_emit_level(cassette, time, TVC64_SYNC_FREQ*2, +1);
+ tvc64_emit_level(cassette, time, TVC64_SYNC_FREQ*2, -1);
+
+ // first data sector contain the data header
+ buff_idx = 0;
+ tmp_buff[buff_idx++] = 0x00;
+ tmp_buff[buff_idx++] = 0x6a;
+ tmp_buff[buff_idx++] = 0x00; // data sector
+ tmp_buff[buff_idx++] = 0x11; // not puffered
+ tmp_buff[buff_idx++] = 0x00; // not write protected
+ tmp_buff[buff_idx++] = (UINT8)((cas_size / 256) + ((cas_size % 256) > 0 ? 1 : 0)); // number of sectors
+
+ UINT8 sect_num = 1;
+ int sector_num = cas_size / 256;
+ for (int i=0; i<=sector_num; i++)
+ {
+ tmp_buff[buff_idx++] = sect_num++; // sector number
+
+ // sector size
+ if (i == sector_num)
+ tmp_buff[buff_idx++] = cas_size % 256;
+ else
+ tmp_buff[buff_idx++] = 0x00;
+
+ // sector data
+ int sector_size = (i == sector_num) ? (cas_size % 256) : 256;
+ for (int z=0; z < sector_size; z++)
+ cassette_image_read(cassette, &tmp_buff[buff_idx++], TVC64_HEADER_BYTES + i*256 + z, 1);
+
+ if (i == sector_num || ((i+1) == sector_num && (cas_size % 256 ) == 0))
+ tmp_buff[buff_idx++] = 0xff; // last sector
+ else
+ tmp_buff[buff_idx++] = 0x00; // no last sector
+
+ // sector crc
+ crc = tvc64_calc_crc(tmp_buff, buff_idx);
+ tmp_buff[buff_idx++] = crc & 0xff;
+ tmp_buff[buff_idx++] = (crc>>8) & 0xff;
+
+ // output the sector
+ for (int z=0; z<buff_idx; z++)
+ tvc64_output_byte(cassette, time, tmp_buff[z]);
+
+ buff_idx = 0;
+ }
+
+ // 5 post data cycles
+ tvc64_output_predata(cassette, time, 5);
+
+ // 1 sec silence
+ tvc64_emit_level(cassette, time, 1, 0);
+
+ return CASSETTE_ERROR_SUCCESS;
+}
+
+static casserr_t tvc64_cassette_identify(cassette_image *cassette, struct CassetteOptions *opts)
+{
+ UINT8 byte;
+ cassette_image_read(cassette, &byte, 0, 1);
+
+ if (byte == 0x11)
+ {
+ opts->bits_per_sample = 16;
+ opts->channels = 1;
+ opts->sample_frequency = 44100;
+ return CASSETTE_ERROR_SUCCESS;
+ }
+
+ return CASSETTE_ERROR_INVALIDIMAGE;
+}
+
+static const struct CassetteFormat tvc64_cassette_image_format =
+{
+ "cas",
+ tvc64_cassette_identify,
+ tvc64_cassette_load,
+ NULL
+};
+
+CASSETTE_FORMATLIST_START(tvc64_cassette_formats)
+ CASSETTE_FORMAT(tvc64_cassette_image_format)
+CASSETTE_FORMATLIST_END