summaryrefslogtreecommitdiffstatshomepage
diff options
context:
space:
mode:
author R. Belmont <rb6502@users.noreply.github.com>2008-07-28 05:46:29 +0000
committer R. Belmont <rb6502@users.noreply.github.com>2008-07-28 05:46:29 +0000
commit67faaeb473f9a579796e2a1f23acdfb515b22f81 (patch)
treee29573ee0c0a286b0acc046bab22da332fc9cdf1
parent867d51a2bc467106df98c67e22f52505c08e047a (diff)
AICA updates [Deunan Knute, ajax16384, R. Belmont]
- Fixed ADPCM decoder to remove bad optimization and match YMZ280B. DC offset is fixed and output quality is higher - Improved handling of slot monitor and timers B and C - Simplified interpolation code
-rw-r--r--src/emu/sound/aica.c66
1 files changed, 20 insertions, 46 deletions
diff --git a/src/emu/sound/aica.c b/src/emu/sound/aica.c
index cf969ed0b1f..ebdf29c752c 100644
--- a/src/emu/sound/aica.c
+++ b/src/emu/sound/aica.c
@@ -123,12 +123,10 @@ struct _SLOT
struct _LFO ALFO; //Amplitude LFO
int slot;
int cur_sample; //current ADPCM sample
- int nxt_sample; //next ADPCM sample
int cur_quant; //current ADPCM step
- int nxt_quant; //next ADPCM step
- int curstep, nxtstep;
+ int curstep;
int cur_lpquant, cur_lpsample, cur_lpstep;
- UINT8 *adbase, *nxtbase, *adlpbase;
+ UINT8 *adbase, *adlpbase;
UINT8 mslc; // monitored?
};
@@ -442,10 +440,11 @@ static void InitADPCM(int *PrevSignal, int *PrevQuant)
*PrevQuant=0x7f;
}
-INLINE signed short DecodeADPCM(int *PrevSignal, unsigned char Delta, int *PrevQuant)
+INLINE signed short inline DecodeADPCM(int *PrevSignal, unsigned char Delta, int *PrevQuant)
{
- *PrevSignal+=(*PrevQuant*quant_mul[Delta&15])>>(3);
- *PrevSignal=ICLIP16(*PrevSignal);
+ int x = *PrevQuant * quant_mul [Delta & 15];
+ x = *PrevSignal + ((int)(x + ((UINT32)x >> 29)) >> 3);
+ *PrevSignal=ICLIP16(x);
*PrevQuant=(*PrevQuant*TableQuant[Delta&7])>>ADPCMSHIFT;
*PrevQuant=(*PrevQuant<0x7f)?0x7f:((*PrevQuant>0x6000)?0x6000:*PrevQuant);
return *PrevSignal;
@@ -471,10 +470,9 @@ static void AICA_StartSlot(struct _AICA *AICA, struct _SLOT *slot)
UINT8 *base;
UINT32 curstep, steps_to_go;
- slot->curstep = slot->nxtstep = 0;
- slot->adbase = slot->nxtbase = (unsigned char *) (AICA->AICARAM+((SA(slot))&0x7fffff));
+ slot->curstep = 0;
+ slot->adbase = (unsigned char *) (AICA->AICARAM+((SA(slot))&0x7fffff));
InitADPCM(&(slot->cur_sample), &(slot->cur_quant));
- InitADPCM(&(slot->nxt_sample), &(slot->nxt_quant));
InitADPCM(&(slot->cur_lpsample), &(slot->cur_lpquant));
// walk to the ADPCM state at LSA
@@ -1085,12 +1083,16 @@ INLINE INT32 AICA_UpdateSlot(struct _AICA *AICA, struct _SLOT *slot)
{
UINT8 *base= slot->adbase;
INT32 s;
+ int cur_sample; //current ADPCM sample
+ int nxt_sample; //next ADPCM sample
INT32 fpart=slot->cur_addr&((1<<SHIFT)-1);
- UINT32 steps_to_go = addr1, curstep = slot->curstep;
+ UINT32 steps_to_go = addr2, curstep = slot->curstep;
if (slot->adbase)
{
- // seek to the current sample
+ cur_sample = slot->cur_sample; // may already contains current decoded sample
+
+ // seek to the interpolation sample
while (curstep < steps_to_go)
{
int shift1, delta1;
@@ -1102,33 +1104,15 @@ INLINE INT32 AICA_UpdateSlot(struct _AICA *AICA, struct _SLOT *slot)
{
base++;
}
+ if (curstep == addr1)
+ cur_sample = slot->cur_sample;
}
+ nxt_sample = slot->cur_sample;
slot->adbase = base;
slot->curstep = curstep;
- base = slot->nxtbase;
- curstep = slot->nxtstep;
- steps_to_go = addr2;
-
- // seek to the interpolation sample
- while (curstep < steps_to_go)
- {
- int shift1, delta1;
- shift1 = 4*((curstep&1));
- delta1 = (*base>>shift1)&0xf;
- DecodeADPCM(&(slot->nxt_sample),delta1,&(slot->nxt_quant));
- curstep++;
- if (!(curstep & 1))
- {
- base++;
- }
- }
-
- slot->nxtbase = base;
- slot->nxtstep = curstep;
-
- s=(int) slot->cur_sample*((1<<SHIFT)-fpart)+(int) slot->nxt_sample*fpart;
+ s=(int)cur_sample*((1<<SHIFT)-fpart)+(int)nxt_sample*fpart;
}
else
{
@@ -1171,7 +1155,7 @@ INLINE INT32 AICA_UpdateSlot(struct _AICA *AICA, struct _SLOT *slot)
rem_addr = *slot_addr[addr_select] - (LEA(slot)<<SHIFT);
*slot_addr[addr_select]=(LSA(slot)<<SHIFT) + rem_addr;
- if(PCMS(slot)>=2 && addr_select==0)
+ if(PCMS(slot)>=2)
{
// restore the state @ LSA - the sampler will naturally walk to (LSA + remainder)
slot->adbase = &AICA->AICARAM[SA(slot)+(LSA(slot)/2)];
@@ -1184,16 +1168,6 @@ INLINE INT32 AICA_UpdateSlot(struct _AICA *AICA, struct _SLOT *slot)
// printf("Looping: slot_addr %x LSA %x LEA %x step %x base %x\n", *slot_addr[addr_select]>>SHIFT, LSA(slot), LEA(slot), slot->curstep, slot->adbase);
}
- else if(PCMS(slot)>=2 && addr_select==1)
- {
- slot->nxtbase = &AICA->AICARAM[SA(slot)+(LSA(slot)/2)];
- slot->nxtstep = LSA(slot);
- if (PCMS(slot) == 2)
- {
- slot->nxt_sample = slot->cur_lpsample;
- slot->nxt_quant = slot->cur_lpquant;
- }
- }
}
break;
}
@@ -1212,7 +1186,7 @@ INLINE INT32 AICA_UpdateSlot(struct _AICA *AICA, struct _SLOT *slot)
if(slot->mslc)
{
- AICA->udata.data[0x12/2] = addr1;
+ AICA->udata.data[0x14/2] = addr1;
if (!(AFSEL(AICA)))
{
AICA->udata.data[0x10/2] |= slot->EG.state<<13;