diff options
Diffstat (limited to 'src/mame/audio/cclimber.c')
-rw-r--r-- | src/mame/audio/cclimber.c | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/src/mame/audio/cclimber.c b/src/mame/audio/cclimber.c new file mode 100644 index 00000000000..dd6da27e75a --- /dev/null +++ b/src/mame/audio/cclimber.c @@ -0,0 +1,91 @@ +#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 +}; + +struct Samplesinterface cclimber_samples_interface = +{ + 1, + NULL, + cclimber_sh_start +}; |