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cgenie.cpp: expanded .cas support so that also files created by

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Genieous emulator can be loaded. [Fabio Priuli]
This commit is contained in:
etabeta78 2016-04-24 16:07:06 +02:00
parent 96d123b42c
commit 24900375fd
1 changed files with 40 additions and 30 deletions
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70
src/lib/formats/cgen_cas.cpp
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@ -7,6 +7,16 @@ Support for EACA Colour Genie .cas cassette images
Current state: Not working. Only the sync signal and 0x66 byte get
recognized.
NOTE: There exist multiples type of .cas files for Colour Genie
- the original one from Jurgen's emu, which starts with TAPE_HEADER
below, followed by the sync signal, without the 255 leading 0xaa
bytes (which are added at loading time)
- a newer type from Genieous emu, which does not start with TAPE_HEADER
but contains the 255 leading 0xaa bytes (which are now skipped below)
- an alternative type (from Genieous as well?) without TAPE_HEADER
and without the 255 leading 0xaa bytes
We now support these three types below...
********************************************************************/
#include <assert.h>
@ -25,22 +35,21 @@ static int level;
static int cgenie_output_byte(INT16 *buffer, int sample_count, UINT8 data)
{
int i;
int samples = 0;
for ( i = 0; i < 8; i++ )
for (int i = 0; i < 8; i++)
{
/* Output bit boundary */
// Output bit boundary
level ^= 1;
if ( buffer )
buffer[ sample_count + samples ] = level ? SMPHI : SMPLO;
if (buffer)
buffer[sample_count + samples] = level ? SMPHI : SMPLO;
samples++;
/* Output bit */
if ( data & 0x80 )
// Output bit
if (data & 0x80)
level ^= 1;
if ( buffer )
buffer[ sample_count + samples ] = level ? SMPHI : SMPLO;
if (buffer)
buffer[sample_count + samples] = level ? SMPHI : SMPLO;
samples++;
data <<= 1;
@ -51,46 +60,47 @@ static int cgenie_output_byte(INT16 *buffer, int sample_count, UINT8 data)
static int cgenie_handle_cas(INT16 *buffer, const UINT8 *casdata)
{
int i, data_pos, sample_count;
int data_pos, sample_count;
data_pos = 0;
sample_count = 0;
level = 0;
/* Check for presence of optional header */
if ( ! memcmp( casdata, TAPE_HEADER, sizeof(TAPE_HEADER) - 1 ) )
// Check for presence of optional header
if (!memcmp(casdata, TAPE_HEADER, sizeof(TAPE_HEADER) - 1))
{
/* Search for 0x00 or end of file */
while ( data_pos < cas_size && casdata[data_pos] )
// Search for 0x00 or end of file
while (data_pos < cas_size && casdata[data_pos])
data_pos++;
/* If we're at the end of the file it's not a valid .cas file */
if ( data_pos == cas_size )
// If we're at the end of the file it's not a valid .cas file
if (data_pos == cas_size)
return -1;
/* Skip the 0x00 byte */
// Skip the 0x00 byte
data_pos++;
}
/* If we're at the end of the file it's not a valid .cas file */
if ( data_pos == cas_size )
// If we're at the end of the file it's not a valid .cas file
if (data_pos == cas_size)
return -1;
/* Check for beginning of tape file marker */
if ( casdata[data_pos] != 0x66 )
// Check for beginning of tape file marker (possibly skipping the 0xaa header)
if (casdata[data_pos] != 0x66 && casdata[data_pos + 0xff] != 0x66)
return -1;
/* Create header */
for ( i = 0; i < 256; i++ )
sample_count += cgenie_output_byte( buffer, sample_count, 0xaa );
// Create header, if not present in the file
if (casdata[data_pos] == 0x66)
for (int i = 0; i < 256; i++)
sample_count += cgenie_output_byte(buffer, sample_count, 0xaa);
/* Start outputting data */
while( data_pos < cas_size )
// Start outputting data
while (data_pos < cas_size)
{
sample_count += cgenie_output_byte( buffer, sample_count, casdata[data_pos] );
sample_count += cgenie_output_byte(buffer, sample_count, casdata[data_pos]);
data_pos++;
}
sample_count += cgenie_output_byte( buffer, sample_count, 0x00 );
sample_count += cgenie_output_byte(buffer, sample_count, 0x00);
return sample_count;
}
@ -100,7 +110,7 @@ static int cgenie_handle_cas(INT16 *buffer, const UINT8 *casdata)
********************************************************************/
static int cgenie_cas_fill_wave(INT16 *buffer, int sample_count, UINT8 *bytes)
{
return cgenie_handle_cas( buffer, bytes );
return cgenie_handle_cas(buffer, bytes);
}
@ -111,7 +121,7 @@ static int cgenie_cas_to_wav_size(const UINT8 *casdata, int caslen)
{
cas_size = caslen;
return cgenie_handle_cas( nullptr, casdata );
return cgenie_handle_cas(nullptr, casdata);
}
static const struct CassetteLegacyWaveFiller cgenie_cas_legacy_fill_wave =