mame/src/lib/formats/fm7_cas.c
2013-01-11 07:32:46 +00:00

109 lines
2.5 KiB
C

/*
* Fujitsu FM-7 series cassette handling
*/
#include "fm7_cas.h"
#define WAVE_HIGH 0x5a9e
#define WAVE_LOW -0x5a9e
static int cas_size;
static int fm7_fill_wave(INT16* buffer, UINT8 high, UINT8 low, int sample_pos)
{
UINT16 data = (high << 8) + low;
int sample_count = 0;
int x = 0;
int count = (data & 0x7fff);
if(data & 0x8000)
{
for(x=0;x<count;x++)
{
if(buffer)
buffer[sample_pos+x] = WAVE_HIGH;
}
}
else
{
for(x=0;x<count;x++)
{
if(buffer)
buffer[sample_pos+x] = WAVE_LOW;
}
}
sample_count += count;
return sample_count;
}
static int fm7_handle_t77(INT16* buffer, const UINT8* casdata)
{
int sample_count = 0;
int data_pos = 16;
if(memcmp(casdata, "XM7 TAPE IMAGE 0",16)) // header check
return -1;
while(data_pos < cas_size)
{
sample_count += fm7_fill_wave(buffer,casdata[data_pos],casdata[data_pos+1],sample_count);
data_pos+=2;
}
return sample_count;
}
/*******************************************************************
Calculate the number of samples needed for this tape image
********************************************************************/
static int fm7_cas_to_wav_size (const UINT8 *casdata, int caslen)
{
cas_size = caslen;
return fm7_handle_t77(NULL,casdata);
}
/*******************************************************************
Generate samples for the tape image
********************************************************************/
static int fm7_cas_fill_wave(INT16 *buffer, int sample_count, UINT8 *bytes)
{
return fm7_handle_t77(buffer,bytes);
}
static const struct CassetteLegacyWaveFiller fm7_legacy_fill_wave =
{
fm7_cas_fill_wave, /* fill_wave */
-1, /* chunk_size */
0, /* chunk_samples */
fm7_cas_to_wav_size, /* chunk_sample_calc */
110250, /* sample_frequency */
0, /* header_samples */
0 /* trailer_samples */
};
static casserr_t fm7_cas_identify(cassette_image *cassette, struct CassetteOptions *opts)
{
return cassette_legacy_identify(cassette, opts, &fm7_legacy_fill_wave);
}
static casserr_t fm7_cas_load(cassette_image *cassette)
{
return cassette_legacy_construct(cassette, &fm7_legacy_fill_wave);
}
static const struct CassetteFormat fm7_cassette_format = {
"t77",
fm7_cas_identify,
fm7_cas_load,
NULL
};
CASSETTE_FORMATLIST_START(fm7_cassette_formats)
CASSETTE_FORMAT(fm7_cassette_format)
CASSETTE_FORMATLIST_END