static int ace_handle_tap(INT16 *buffer, const UINT8 *casdata)
{
int data_pos, sample_count;
/* Make sure the file starts with a valid header */
if ( cas_size < 0x1C )
return -1;
if ( casdata[0] != 0x1A || casdata[1] != 0x00 )
return -1;
data_pos = 0;
sample_count = 0;
while( data_pos < cas_size )
{
UINT16 block_size;
int i;
/* Handle a block of tape data */
block_size = casdata[data_pos] + ( casdata[data_pos + 1] << 8 );
data_pos += 2;
/* Make sure there are enough bytes left */
if ( data_pos > cas_size )
return -1;
/* 2 seconds silence */
sample_count += ace_tap_silence( buffer, sample_count, 2 * 44100 );
/* Add pilot tone samples: 4096 for header, 512 for data */
for( i = ( block_size == 0x001A ) ? 4096 : 512; i; i-- )
sample_count += ace_tap_cycle( buffer, sample_count, 27, 27 );
/* Sync samples */
sample_count += ace_tap_cycle( buffer, sample_count, 8, 11 );
/* Output block type identification byte */
sample_count += ace_tap_byte( buffer, sample_count, ( block_size != 0x001A ) ? 0xFF : 0x00 );
/* Data samples */
for ( ; block_size ; data_pos++, block_size-- )
sample_count += ace_tap_byte( buffer, sample_count, casdata[data_pos] );
/* End mark samples */
sample_count += ace_tap_cycle( buffer, sample_count, 12, 57 );
/* 3 seconds silence */
sample_count += ace_tap_silence( buffer, sample_count, 3 * 44100 );
}
return sample_count;
}
INLINE int ace_tap_byte(INT16 *buffer, int sample_pos, UINT8 data)
{
int i, samples;
samples = 0;
for ( i = 0; i < 8; i++ )
{
if ( data & 0x80 )
samples += ace_tap_cycle( buffer, sample_pos + samples, 21, 22 );
else
samples += ace_tap_cycle( buffer, sample_pos + samples, 10, 11 );
data <<= 1;
}
return samples;
}
static inline int ace_tap_byte(int16_t *buffer, int sample_pos, uint8_t data)
{
int i, samples;
samples = 0;
for ( i = 0; i < 8; i++ )
{
if ( data & 0x80 )
samples += ace_tap_cycle( buffer, sample_pos + samples, 21, 22 );
else
samples += ace_tap_cycle( buffer, sample_pos + samples, 10, 11 );
data <<= 1;
}
return samples;
}
