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k053260: delta PCM decoding rolls over instead of clipping; fixes MT#1007 [Alex Jackson]

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This commit is contained in:
Alex W. Jackson 2014-10-01 05:10:26 +00:00
parent 124d852205
commit 214c4525cc
1 changed files with 10 additions and 15 deletions
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25
src/emu/sound/k053260.c
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@ -128,16 +128,17 @@ INLINE int limit( int val, int max, int min )
void k053260_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples)
{
static const long dpcmcnv[] = { 0,1,2,4,8,16,32,64, -128, -64, -32, -16, -8, -4, -2, -1};
static const INT8 dpcmcnv[] = { 0,1,2,4,8,16,32,64, -128, -64, -32, -16, -8, -4, -2, -1};
int i, j, lvol[4], rvol[4], play[4], loop[4], ppcm_data[4], ppcm[4];
unsigned char *rom[4];
int lvol[4], rvol[4], play[4], loop[4], ppcm[4];
UINT8 *rom[4];
UINT32 delta[4], end[4], pos[4];
INT8 ppcm_data[4];
int dataL, dataR;
signed char d;
INT8 d;
/* precache some values */
for ( i = 0; i < 4; i++ ) {
for ( int i = 0; i < 4; i++ ) {
rom[i]= &m_rom[m_channels[i].start + ( m_channels[i].bank << 16 )];
delta[i] = m_delta_table[m_channels[i].rate];
lvol[i] = m_channels[i].volume * m_channels[i].pan;
@ -152,10 +153,10 @@ void k053260_device::sound_stream_update(sound_stream &stream, stream_sample_t *
delta[i] /= 2;
}
for ( j = 0; j < samples; j++ ) {
for ( int j = 0; j < samples; j++ ) {
dataL = dataR = 0;
for ( i = 0; i < 4; i++ ) {
for ( int i = 0; i < 4; i++ ) {
/* see if the voice is on */
if ( play[i] ) {
/* see if we're done */
@ -183,13 +184,7 @@ void k053260_device::sound_stream_update(sound_stream &stream, stream_sample_t *
newdata = ( ( rom[i][pos[i] >> BASE_SHIFT] ) ) & 0x0f; /*low nybble*/
}
ppcm_data[i] = (( ( ppcm_data[i] * 62 ) >> 6 ) + dpcmcnv[newdata]);
if ( ppcm_data[i] > 127 )
ppcm_data[i] = 127;
else
if ( ppcm_data[i] < -128 )
ppcm_data[i] = -128;
ppcm_data[i] += dpcmcnv[newdata];
}
@ -215,7 +210,7 @@ void k053260_device::sound_stream_update(sound_stream &stream, stream_sample_t *
}
/* update the regs now */
for ( i = 0; i < 4; i++ ) {
for ( int i = 0; i < 4; i++ ) {
m_channels[i].pos = pos[i];
m_channels[i].play = play[i];
m_channels[i].ppcm_data = ppcm_data[i];