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#include "driver.h"
#include "sound/ay8910.h"
#include "sound/samples.h"
#include "includes/cclimber.h"
/* macro to convert 4-bit unsigned samples to 16-bit signed samples */
#define SAMPLE_CONV4(a) (0x1111*((a&0x0f))-0x8000)
#define SND_CLOCK 3072000 /* 3.072 MHz */
static INT16 *samplebuf; /* buffer to decode samples at run time */
static void cclimber_sh_start(void)
{
samplebuf = 0;
if (memory_region(REGION_SOUND1))
samplebuf = auto_malloc(sizeof(*samplebuf)*2*memory_region_length(REGION_SOUND1));
}
static void cclimber_play_sample(int start,int freq,int volume)
{
int len;
const UINT8 *rom = memory_region(REGION_SOUND1);
if (!rom) return;
/* decode the rom samples */
len = 0;
while (start + len < memory_region_length(REGION_SOUND1) && rom[start+len] != 0x70)
{
int sample;
sample = (rom[start + len] & 0xf0) >> 4;
samplebuf[2*len] = SAMPLE_CONV4(sample) * volume / 31;
sample = rom[start + len] & 0x0f;
samplebuf[2*len + 1] = SAMPLE_CONV4(sample) * volume / 31;
len++;
}
sample_start_raw(0,samplebuf,2 * len,freq,0);
}
static int sample_num,sample_freq,sample_volume;
static WRITE8_HANDLER( cclimber_sample_select_w )
{
sample_num = data;
}
WRITE8_HANDLER( cclimber_sample_rate_w )
{
/* calculate the sampling frequency */
sample_freq = SND_CLOCK / 4 / (256 - data);
}
WRITE8_HANDLER( cclimber_sample_volume_w )
{
sample_volume = data & 0x1f; /* range 0-31 */
}
WRITE8_HANDLER( cclimber_sample_trigger_w )
{
if (data == 0)
return;
cclimber_play_sample(32 * sample_num,sample_freq,sample_volume);
}
struct AY8910interface cclimber_ay8910_interface =
{
0,
0,
cclimber_sample_select_w,
0
};
const struct Samplesinterface cclimber_samples_interface =
{
1,
NULL,
cclimber_sh_start
};
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