BizHawk/psx/octoshock/psx/spu_reverb.inc

218 lines
5.9 KiB
C++

/******************************************************************************/
/* Mednafen Sony PS1 Emulation Module */
/******************************************************************************/
/* spu_reverb.inc:
** Copyright (C) 2011-2016 Mednafen Team
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of the GNU General Public License
** as published by the Free Software Foundation; either version 2
** of the License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software Foundation, Inc.,
** 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
static int16 ReverbSat(int32 samp) MDFN_WARN_UNUSED_RESULT;
static INLINE int16 ReverbSat(int32 samp)
{
if(samp > 32767)
samp = 32767;
if(samp < -32768)
samp = -32768;
return(samp);
}
static INLINE int16 ReverbNeg(int16 samp)
{
if(samp == -32768)
return 0x7FFF;
return -samp;
}
INLINE uint32 PS_SPU::Get_Reverb_Offset(uint32 in_offset)
{
uint32 offset = ReverbCur + (in_offset & 0x3FFFF);
offset += ReverbWA & ((int32)(offset << 13) >> 31);
offset &= 0x3FFFF;
// For debugging in case there are any problems with games misprogramming the reverb registers in a race-conditiony manner that
// causes important data in SPU RAM to be trashed:
//if(offset < ReverbWA)
// printf("BARF: offset=%05x reverbwa=%05x reverbcur=%05x in_offset=%05x\n", offset, ReverbWA, ReverbCur, in_offset & 0x3FFFF);
return(offset);
}
int16 NO_INLINE PS_SPU::RD_RVB(uint16 raw_offs, int32 extra_offs)
{
return ReadSPURAM(Get_Reverb_Offset((raw_offs << 2) + extra_offs));
}
void NO_INLINE PS_SPU::WR_RVB(uint16 raw_offs, int16 sample)
{
if(SPUControl & 0x80)
WriteSPURAM(Get_Reverb_Offset(raw_offs << 2), sample);
}
//
// Zeroes optimized out; middle removed too(it's 16384)
static const int16 ResampTable[20] =
{
-1, 2, -10, 35, -103, 266, -616, 1332, -2960, 10246, 10246, -2960, 1332, -616, 266, -103, 35, -10, 2, -1,
};
static INLINE int32 Reverb4422(const int16 *src)
{
int32 out = 0; // 32-bits is adequate(it won't overflow)
for(unsigned i = 0; i < 20; i++)
out += ResampTable[i] * src[i * 2];
// Middle non-zero
out += 0x4000 * src[19];
out >>= 15;
clamp(&out, -32768, 32767);
return(out);
}
template<bool phase>
static INLINE int32 Reverb2244(const int16 *src)
{
int32 out; // 32-bits is adequate(it won't overflow)
if(phase)
{
// Middle non-zero
out = src[9];
}
else
{
out = 0;
for(unsigned i = 0; i < 20; i++)
out += ResampTable[i] * src[i];
out >>= 14;
clamp(&out, -32768, 32767);
}
return(out);
}
static int32 IIASM(const int16 IIR_ALPHA, const int16 insamp)
{
if(MDFN_UNLIKELY(IIR_ALPHA == -32768))
{
//const int32 iai_adj = sign_x_to_s32(17, (32768 - IIR_ALPHA));
//tmp = iai_adj * in_samp
if(insamp == -32768)
return 0;
else
return insamp * -65536;
}
else
return insamp * (32768 - IIR_ALPHA);
}
//
// Take care to thoroughly test the reverb resampling code when modifying anything that uses RvbResPos.
//
INLINE void PS_SPU::RunReverb(const int32* in, int32* out)
{
int32 upsampled[2] = { 0, 0 };
for(unsigned lr = 0; lr < 2; lr++)
{
RDSB[lr][RvbResPos | 0x00] = in[lr];
RDSB[lr][RvbResPos | 0x40] = in[lr]; // So we don't have to &/bounds check in our MAC loop
}
if(RvbResPos & 1)
{
int32 downsampled[2];
for(unsigned lr = 0; lr < 2; lr++)
downsampled[lr] = Reverb4422(&RDSB[lr][(RvbResPos - 38) & 0x3F]);
//
// Run algorithm
//
for(unsigned lr = 0; lr < 2; lr++)
{
const int16 IIR_INPUT_A = ReverbSat((((RD_RVB(IIR_SRC_A[lr ^ 0]) * IIR_COEF) >> 14) + ((downsampled[lr] * IN_COEF[lr]) >> 14)) >> 1);
const int16 IIR_INPUT_B = ReverbSat((((RD_RVB(IIR_SRC_B[lr ^ 1]) * IIR_COEF) >> 14) + ((downsampled[lr] * IN_COEF[lr]) >> 14)) >> 1);
const int16 IIR_A = ReverbSat((((IIR_INPUT_A * IIR_ALPHA) >> 14) + (IIASM(IIR_ALPHA, RD_RVB(IIR_DEST_A[lr], -1)) >> 14)) >> 1);
const int16 IIR_B = ReverbSat((((IIR_INPUT_B * IIR_ALPHA) >> 14) + (IIASM(IIR_ALPHA, RD_RVB(IIR_DEST_B[lr], -1)) >> 14)) >> 1);
WR_RVB(IIR_DEST_A[lr], IIR_A);
WR_RVB(IIR_DEST_B[lr], IIR_B);
const int32 ACC = ((RD_RVB(ACC_SRC_A[lr]) * ACC_COEF_A) >> 14) +
((RD_RVB(ACC_SRC_B[lr]) * ACC_COEF_B) >> 14) +
((RD_RVB(ACC_SRC_C[lr]) * ACC_COEF_C) >> 14) +
((RD_RVB(ACC_SRC_D[lr]) * ACC_COEF_D) >> 14);
const int16 FB_A = RD_RVB(MIX_DEST_A[lr] - FB_SRC_A);
const int16 FB_B = RD_RVB(MIX_DEST_B[lr] - FB_SRC_B);
const int16 MDA = ReverbSat((ACC + ((FB_A * ReverbNeg(FB_ALPHA)) >> 14)) >> 1);
const int16 MDB = ReverbSat(FB_A + ((((MDA * FB_ALPHA) >> 14) + ((FB_B * ReverbNeg(FB_X)) >> 14)) >> 1));
const int16 IVB = ReverbSat(FB_B + ((MDB * FB_X) >> 15));
WR_RVB(MIX_DEST_A[lr], MDA);
WR_RVB(MIX_DEST_B[lr], MDB);
#if 0
{
static uint32 sqcounter;
RUSB[lr][(RvbResPos >> 1) | 0x20] = RUSB[lr][RvbResPos >> 1] = ((sqcounter & 0xFF) == 0) ? 0x8000 : 0x0000; //((sqcounter & 0x80) ? 0x7000 : 0x9000);
sqcounter += lr;
}
#else
RUSB[lr][(RvbResPos >> 1) | 0x20] = RUSB[lr][RvbResPos >> 1] = IVB; // Output sample
#endif
}
//
//
//
ReverbCur = (ReverbCur + 1) & 0x3FFFF;
if(!ReverbCur)
ReverbCur = ReverbWA;
for(unsigned lr = 0; lr < 2; lr++)
upsampled[lr] = Reverb2244<false>(&RUSB[lr][((RvbResPos >> 1) - 19) & 0x1F]);
}
else
{
for(unsigned lr = 0; lr < 2; lr++)
upsampled[lr] = Reverb2244<true>(&RUSB[lr][((RvbResPos >> 1) - 19) & 0x1F]);
}
RvbResPos = (RvbResPos + 1) & 0x3F;
for(unsigned lr = 0; lr < 2; lr++)
{
#if 0
if(!lr)
printf("%d\n", (-upsampled[lr]) >> 1);
#endif
out[lr] = upsampled[lr];
}
}