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Diffstat (limited to 'trunk/src/lib/formats/x1_tap.c')
-rw-r--r--trunk/src/lib/formats/x1_tap.c127
1 files changed, 127 insertions, 0 deletions
diff --git a/trunk/src/lib/formats/x1_tap.c b/trunk/src/lib/formats/x1_tap.c
new file mode 100644
index 00000000000..0f697aea9e1
--- /dev/null
+++ b/trunk/src/lib/formats/x1_tap.c
@@ -0,0 +1,127 @@
+/*
+ *
+ * Sharp X1 TAP image format
+ *
+ * "New" header format:
+ * 0x00: Index - must be "TAPE" (4 bytes)
+ * 0x04: Image title. (null-terminated string, 17 bytes)
+ * 0x15: Reserved (5 bytes)
+ * 0x1a: Write protect (bit 4, 1 byte)
+ * 0x1b: Format (bit 0, 1 byte)
+ * if bit 0 is high, uses "speed limit sampling method"
+ * 0x1c: Sample rate, per bit (in Hz, 4 bytes)
+ * 0x20: Tape data size, in bits (4 bytes)
+ * 0x24: Tape position (4 bytes, usually 0)
+ * 0x28: Tape data (data size / 8)
+ *
+ * "Old" header format:
+ * 0x00: Sampling rate (4 bytes)
+ *
+ */
+
+#include "x1_tap.h"
+
+#define WAVE_HIGH 0x5a9e
+#define WAVE_LOW -0x5a9e
+
+static int cas_size;
+static int samplerate;
+
+static int x1_fill_wave(INT16* buffer, UINT8 data, int sample_pos)
+{
+ int x;
+ int sample_count = 0;
+
+ // one byte = 8 samples
+ for(x=0;x<8;x++)
+ {
+ if(buffer)
+ buffer[sample_pos+x] = (data & (1 << (7-x))) ? WAVE_HIGH : WAVE_LOW;
+ sample_count++;
+ }
+
+ return sample_count;
+}
+
+static int x1_handle_tap(INT16* buffer, const UINT8* casdata)
+{
+ int sample_count = 0;
+ int data_pos = 0x28;
+
+ if(memcmp(casdata, "TAPE",4)) // header check
+ {
+ LOG_FORMATS("TAP: image is not a 'new' format TAP image\n");
+ return -1;
+ }
+ if(samplerate != 8000)
+ {
+ LOG_FORMATS("TAP: images that are not 8000Hz are not yet supported\n");
+ return -1;
+ }
+
+ while(sample_count < cas_size)
+ {
+ sample_count += x1_fill_wave(buffer,casdata[data_pos],sample_count);
+ data_pos++;
+ }
+
+ return sample_count;
+}
+
+/*******************************************************************
+ Calculate the number of samples needed for this tape image
+********************************************************************/
+static int x1_cas_to_wav_size (const UINT8 *casdata, int caslen)
+{
+ UINT32 ret;
+
+ ret = casdata[0x20] | (casdata[0x21] << 8) | (casdata[0x22] << 16) | (casdata[0x23] << 24);
+ cas_size = ret;
+
+ samplerate = casdata[0x1c] | (casdata[0x1d] << 8) | (casdata[0x1e] << 16) | (casdata[0x1f] << 24);
+
+ return ret;
+}
+
+/*******************************************************************
+ Generate samples for the tape image
+********************************************************************/
+static int x1_cas_fill_wave(INT16 *buffer, int sample_count, UINT8 *bytes)
+{
+ return x1_handle_tap(buffer,bytes);
+}
+
+static const struct CassetteLegacyWaveFiller x1_legacy_fill_wave =
+{
+ x1_cas_fill_wave, /* fill_wave */
+ -1, /* chunk_size */
+ 0, /* chunk_samples */
+ x1_cas_to_wav_size, /* chunk_sample_calc */
+ 8000, /* sample_frequency */
+ 0, /* header_samples */
+ 0 /* trailer_samples */
+};
+
+static casserr_t x1_cas_identify(cassette_image *cassette, struct CassetteOptions *opts)
+{
+ return cassette_legacy_identify(cassette, opts, &x1_legacy_fill_wave);
+}
+
+
+
+static casserr_t x1_cas_load(cassette_image *cassette)
+{
+ return cassette_legacy_construct(cassette, &x1_legacy_fill_wave);
+}
+
+
+static const struct CassetteFormat x1_cassette_format = {
+ "tap",
+ x1_cas_identify,
+ x1_cas_load,
+ NULL
+};
+
+CASSETTE_FORMATLIST_START(x1_cassette_formats)
+ CASSETTE_FORMAT(x1_cassette_format)
+CASSETTE_FORMATLIST_END