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[Core/YM2612] fixed configurable DAC resolution support

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This commit is contained in:
EkeEke 2013-06-16 23:34:12 +02:00
parent 4e4c25eda7
commit 3eaa6e56ea
2 changed files with 28 additions and 17 deletions
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1
source/sound/sound.c
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@ -229,6 +229,7 @@ int sound_context_load(uint8 *state)
if ((system_hw & SYSTEM_PBC) == SYSTEM_MD)
{
bufferptr = YM2612LoadContext(state);
YM2612Config(config.dac_bits);
}
else
{

44
source/sound/ym2612.c
View File

@ -613,6 +613,8 @@ static YM2612 ym2612;
static INT32 m2,c1,c2; /* Phase Modulation input for operators 2,3,4 */
static INT32 mem; /* one sample delay memory */
static INT32 out_fm[8]; /* outputs of working channels */
static UINT32 bitmask; /* working channels output bitmasking (DAC quantization) */
INLINE void FM_KEYON(FM_CH *CH , int s )
{
@ -1729,7 +1731,7 @@ INLINE void OPNWriteReg(int r, int v)
setup_connection( CH, c );
break;
}
case 1: /* 0xb4-0xb6 : L , R , AMS , PMS (ym2612/YM2610B/YM2610/YM2608) */
case 1: /* 0xb4-0xb6 : L , R , AMS , PMS */
/* b0-2 PMS */
CH->pms = (v & 7) * 32; /* CH->pms = PM depth * 32 (index in lfo_pm_table) */
@ -1737,8 +1739,8 @@ INLINE void OPNWriteReg(int r, int v)
CH->ams = lfo_ams_depth_shift[(v>>4) & 0x03];
/* PAN : b7 = L, b6 = R */
ym2612.OPN.pan[ c*2 ] = (v & 0x80) ? ~0 : 0;
ym2612.OPN.pan[ c*2+1 ] = (v & 0x40) ? ~0 : 0;
ym2612.OPN.pan[ c*2 ] = (v & 0x80) ? bitmask : 0;
ym2612.OPN.pan[ c*2+1 ] = (v & 0x40) ? bitmask : 0;
break;
}
break;
@ -1768,14 +1770,11 @@ static void reset_channels(FM_CH *CH , int num )
}
/* initialize generic tables */
static void init_tables(unsigned char dac_bits)
static void init_tables(void)
{
signed int d,i,x;
signed int n;
double o,m;
/* DAC precision */
unsigned int mask = ~((1 << (14 - dac_bits)) - 1);
/* build Linear Power Table */
for (x=0; x<TL_RES_LEN; x++)
@ -1796,8 +1795,8 @@ static void init_tables(unsigned char dac_bits)
n <<= 2; /* 13 bits here (as in real chip) */
/* 14 bits (with sign bit) */
tl_tab[ x*2 + 0 ] = n & mask;
tl_tab[ x*2 + 1 ] = -tl_tab[ x*2 + 0 ] & mask;
tl_tab[ x*2 + 0 ] = n;
tl_tab[ x*2 + 1 ] = -tl_tab[ x*2 + 0 ];
/* one entry in the 'Power' table use the following format, xxxxxyyyyyyyys with: */
/* s = sign bit */
@ -1806,8 +1805,8 @@ static void init_tables(unsigned char dac_bits)
/* any value above 13 (included) would be discarded. */
for (i=1; i<13; i++)
{
tl_tab[ x*2+0 + i*2*TL_RES_LEN ] = (tl_tab[ x*2+0 ]>>i) & mask;
tl_tab[ x*2+1 + i*2*TL_RES_LEN ] = -tl_tab[ x*2+0 + i*2*TL_RES_LEN ] & mask;
tl_tab[ x*2+0 + i*2*TL_RES_LEN ] = tl_tab[ x*2+0 ]>>i;
tl_tab[ x*2+1 + i*2*TL_RES_LEN ] = -tl_tab[ x*2+0 + i*2*TL_RES_LEN ];
}
}
@ -1885,7 +1884,7 @@ static void init_tables(unsigned char dac_bits)
void YM2612Init(void)
{
memset(&ym2612,0,sizeof(YM2612));
init_tables(TL_BITS);
init_tables();
}
/* reset OPN registers */
@ -1957,7 +1956,7 @@ void YM2612Write(unsigned int a, unsigned int v)
switch( addr )
{
case 0x2a: /* DAC data (ym2612) */
ym2612.dacout = ((int)v - 0x80) << 6; /* level unknown (5 is too low, 8 is too loud) */
ym2612.dacout = ((int)v - 0x80) << 6; /* convert to 14-bit output */
break;
case 0x2b: /* DAC Sel (ym2612) */
/* b7 = dac enable */
@ -2052,7 +2051,7 @@ void YM2612Update(int *buffer, int length)
advance_eg_channels(&ym2612.CH[0], ym2612.OPN.eg_cnt);
}
/* 14-bit DAC inputs (range is -8192;+8192) */
/* 14-bit accumulator channels outputs (range is -8192;+8192) */
if (out_fm[0] > 8192) out_fm[0] = 8192;
else if (out_fm[0] < -8192) out_fm[0] = -8192;
if (out_fm[1] > 8192) out_fm[1] = 8192;
@ -2066,7 +2065,7 @@ void YM2612Update(int *buffer, int length)
if (out_fm[5] > 8192) out_fm[5] = 8192;
else if (out_fm[5] < -8192) out_fm[5] = -8192;
/* 6-channels stereo mixing */
/* stereo DAC channels outputs mixing */
lt = ((out_fm[0]) & ym2612.OPN.pan[0]);
rt = ((out_fm[0]) & ym2612.OPN.pan[1]);
lt += ((out_fm[1]) & ym2612.OPN.pan[2]);
@ -2109,8 +2108,19 @@ void YM2612Update(int *buffer, int length)
void YM2612Config(unsigned char dac_bits)
{
/* reinitialize TL table */
init_tables(dac_bits);
int i;
/* DAC precision (normally 9-bit on real hardware, implemented through simple 14-bit channel output bitmasking) */
bitmask = ~((1 << (TL_BITS - dac_bits)) - 1);
/* update L/R panning bitmasks */
for (i=0; i<2*6; i++)
{
if (ym2612.OPN.pan[i])
{
ym2612.OPN.pan[i] = bitmask;
}
}
}
int YM2612LoadContext(unsigned char *state)