summaryrefslogtreecommitdiffstatshomepage
path: root/trunk/src/lib/formats/gtp_cas.c
diff options
context:
space:
mode:
Diffstat (limited to 'trunk/src/lib/formats/gtp_cas.c')
-rw-r--r--trunk/src/lib/formats/gtp_cas.c200
1 files changed, 200 insertions, 0 deletions
diff --git a/trunk/src/lib/formats/gtp_cas.c b/trunk/src/lib/formats/gtp_cas.c
new file mode 100644
index 00000000000..e3756c4dcf7
--- /dev/null
+++ b/trunk/src/lib/formats/gtp_cas.c
@@ -0,0 +1,200 @@
+/*
+
+ Tape support for Glaksija GTP format
+
+ Miodrag Milanovic
+*/
+#include "gtp_cas.h"
+
+
+#define GTP_WAV_FREQUENCY 44100
+#define WAVE_LOW -0x5a9e
+#define WAVE_HIGH 0x5a9e
+#define WAVE_NULL 0
+
+#define GTP_BLOCK_STANDARD 0x00
+#define GTP_BLOCK_TURBO 0x01
+#define GTP_BLOCK_NAME 0x10
+
+static INT16 wave_data;
+static INT16 len;
+
+#define PULSE_WIDTH 30
+#define PERIOD_BASE 150
+#define PERIOD_1 75
+#define PERIOD_0 150
+
+#define INTERBYTE_PAUSE 225
+#define INTERBLOCK_PAUSE 100000
+
+
+static void gtp_output_wave( INT16 **buffer, int length ) {
+ if ( buffer == NULL ) {
+ return;
+ }
+
+ for( ; length > 0; length-- ) {
+ **buffer = wave_data;
+ *buffer = *buffer + 1;
+ }
+}
+
+
+
+static int gtp_mod_1( INT16 **buffer )
+{
+ wave_data = WAVE_LOW;
+ gtp_output_wave(buffer,PULSE_WIDTH);
+ wave_data = WAVE_HIGH;
+ gtp_output_wave(buffer,PULSE_WIDTH);
+ wave_data = WAVE_NULL;
+ gtp_output_wave(buffer,PERIOD_1 - 2 * PULSE_WIDTH);
+ wave_data = WAVE_LOW;
+ gtp_output_wave(buffer,PULSE_WIDTH);
+ wave_data = WAVE_HIGH;
+ gtp_output_wave(buffer,PULSE_WIDTH);
+ wave_data = WAVE_NULL;
+ gtp_output_wave(buffer,PERIOD_1 - 2 * PULSE_WIDTH);
+
+ return PERIOD_1 * 2;
+}
+
+static int gtp_mod_0( INT16 **buffer )
+{
+ wave_data = WAVE_LOW;
+ gtp_output_wave(buffer,PULSE_WIDTH);
+ wave_data = WAVE_HIGH;
+ gtp_output_wave(buffer,PULSE_WIDTH);
+ wave_data = WAVE_NULL;
+ gtp_output_wave(buffer,PERIOD_0 - 2 * PULSE_WIDTH);
+
+ return PERIOD_0;
+}
+
+static int gtp_byte( INT16 **buffer, UINT8 val )
+{
+ UINT8 b;
+ int j,size = 0;
+ for (j=0;j<8;j++) {
+ b = (val >> j) & 1;
+ if (b==0) {
+ size += gtp_mod_0(buffer);
+ } else {
+ size += gtp_mod_1(buffer);
+ }
+ }
+ return size;
+}
+
+static int gtp_sync( INT16 **buffer )
+{
+ int i;
+ int size = 0;
+
+ for(i=0;i<100;i++) {
+ if (i!=0) {
+ // Interbyte pause
+ wave_data = WAVE_NULL;
+ gtp_output_wave(buffer,INTERBYTE_PAUSE);
+ size += INTERBYTE_PAUSE;
+ }
+ size += gtp_byte(buffer,0);
+ }
+ return size;
+}
+
+static int gtp_cas_to_wav_size( const UINT8 *casdata, int caslen ) {
+ int size,n;
+ size = 0;
+ n = 0;
+ if (casdata == NULL) return -1;
+ while(n<caslen) {
+ int block_type = casdata[n];
+ int block_size = casdata[n+2]*256 + casdata[n+1];
+ n+=5;
+ if (block_type==GTP_BLOCK_STANDARD) {
+ // Interblock pause
+ size += INTERBLOCK_PAUSE;
+ size += 100 * (PERIOD_0 * 8 + INTERBYTE_PAUSE) - INTERBYTE_PAUSE;
+ size += (PERIOD_0 * 8 + INTERBYTE_PAUSE) * block_size;
+ }
+ n += block_size;
+ }
+ len = caslen;
+ return size;
+}
+
+static int gtp_cas_fill_wave( INT16 *buffer, int length, UINT8 *bytes ) {
+ int i,size,n;
+ size = 0;
+ n = 0;
+ if (bytes == NULL) return -1;
+ while(n<len)
+ {
+ int block_type = bytes[n];
+ int block_size = bytes[n+2]*256 + bytes[n+1];
+ n+=5;
+ if (block_type==GTP_BLOCK_STANDARD) {
+
+ // Interblock pause
+ wave_data = WAVE_NULL;
+ gtp_output_wave(&buffer,INTERBLOCK_PAUSE);
+ size += INTERBLOCK_PAUSE;
+ size += gtp_sync(&buffer);
+
+ for (i=0;i<block_size;i++) {
+ // Interbyte pause
+ wave_data = WAVE_NULL;
+ gtp_output_wave(&buffer,INTERBYTE_PAUSE);
+ size += INTERBYTE_PAUSE;
+
+ size += gtp_byte(&buffer,bytes[n]);
+ n++;
+ }
+ } else {
+ n += block_size;
+ }
+ }
+ return size;
+}
+
+
+
+
+static const struct CassetteLegacyWaveFiller gtp_legacy_fill_wave = {
+ gtp_cas_fill_wave, /* fill_wave */
+ -1, /* chunk_size */
+ 0, /* chunk_samples */
+ gtp_cas_to_wav_size, /* chunk_sample_calc */
+ GTP_WAV_FREQUENCY, /* sample_frequency */
+ 0, /* header_samples */
+ 0 /* trailer_samples */
+};
+
+
+
+static casserr_t gtp_cassette_identify( cassette_image *cassette, struct CassetteOptions *opts ) {
+ return cassette_legacy_identify( cassette, opts, &gtp_legacy_fill_wave );
+}
+
+
+
+static casserr_t gtp_cassette_load( cassette_image *cassette ) {
+ return cassette_legacy_construct( cassette, &gtp_legacy_fill_wave );
+}
+
+
+
+static const struct CassetteFormat gtp_cassette_format = {
+ "gtp",
+ gtp_cassette_identify,
+ gtp_cassette_load,
+ NULL
+};
+
+
+CASSETTE_FORMATLIST_START(gtp_cassette_formats)
+ CASSETTE_FORMAT(gtp_cassette_format)
+CASSETTE_FORMATLIST_END
+
+