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/*************************************************************************** snes.c File to handle the sound emulation of the Nintendo Super NES. By R. Belmont, adapted from OpenSPC 0.3.99 by Brad Martin with permission. Thanks to Brad and also to Charles Bilyu? of SNeESe. OpenSPC's license terms (the LGPL) follow: --------------------------------------------------------------------------- Copyright Brad Martin. OpenSPC is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. OpenSPC 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 Lesser General Public License for more details. ***************************************************************************/ #include <math.h> #include "driver.h" #include "streams.h" #include "includes/snes.h" static struct { UINT8 enabled; UINT16 counter; emu_timer *timer; } timers[3]; static sound_stream *channel; static UINT8 DSPregs[256]; /* DSP registers */ static UINT8 snes_ipl_region[64]; /* SPC top 64 bytes */ static const int gauss[]= { 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x000, 0x001, 0x001, 0x001, 0x001, 0x001, 0x001, 0x001, 0x001, 0x001, 0x001, 0x001, 0x002, 0x002, 0x002, 0x002, 0x002, 0x002, 0x002, 0x003, 0x003, 0x003, 0x003, 0x003, 0x004, 0x004, 0x004, 0x004, 0x004, 0x005, 0x005, 0x005, 0x005, 0x006, 0x006, 0x006, 0x006, 0x007, 0x007, 0x007, 0x008, 0x008, 0x008, 0x009, 0x009, 0x009, 0x00A, 0x00A, 0x00A, 0x00B, 0x00B, 0x00B, 0x00C, 0x00C, 0x00D, 0x00D, 0x00E, 0x00E, 0x00F, 0x00F, 0x00F, 0x010, 0x010, 0x011, 0x011, 0x012, 0x013, 0x013, 0x014, 0x014, 0x015, 0x015, 0x016, 0x017, 0x017, 0x018, 0x018, 0x019, 0x01A, 0x01B, 0x01B, 0x01C, 0x01D, 0x01D, 0x01E, 0x01F, 0x020, 0x020, 0x021, 0x022, 0x023, 0x024, 0x024, 0x025, 0x026, 0x027, 0x028, 0x029, 0x02A, 0x02B, 0x02C, 0x02D, 0x02E, 0x02F, 0x030, 0x031, 0x032, 0x033, 0x034, 0x035, 0x036, 0x037, 0x038, 0x03A, 0x03B, 0x03C, 0x03D, 0x03E, 0x040, 0x041, 0x042, 0x043, 0x045, 0x046, 0x047, 0x049, 0x04A, 0x04C, 0x04D, 0x04E, 0x050, 0x051, 0x053, 0x054, 0x056, 0x057, 0x059, 0x05A, 0x05C, 0x05E, 0x05F, 0x061, 0x063, 0x064, 0x066, 0x068, 0x06A, 0x06B, 0x06D, 0x06F, 0x071, 0x073, 0x075, 0x076, 0x078, 0x07A, 0x07C, 0x07E, 0x080, 0x082, 0x084, 0x086, 0x089, 0x08B, 0x08D, 0x08F, 0x091, 0x093, 0x096, 0x098, 0x09A, 0x09C, 0x09F, 0x0A1, 0x0A3, 0x0A6, 0x0A8, 0x0AB, 0x0AD, 0x0AF, 0x0B2, 0x0B4, 0x0B7, 0x0BA, 0x0BC, 0x0BF, 0x0C1, 0x0C4, 0x0C7, 0x0C9, 0x0CC, 0x0CF, 0x0D2, 0x0D4, 0x0D7, 0x0DA, 0x0DD, 0x0E0, 0x0E3, 0x0E6, 0x0E9, 0x0EC, 0x0EF, 0x0F2, 0x0F5, 0x0F8, 0x0FB, 0x0FE, 0x101, 0x104, 0x107, 0x10B, 0x10E, 0x111, 0x114, 0x118, 0x11B, 0x11E, 0x122, 0x125, 0x129, 0x12C, 0x130, 0x133, 0x137, 0x13A, 0x13E, 0x141, 0x145, 0x148, 0x14C, 0x150, 0x153, 0x157, 0x15B, 0x15F, 0x162, 0x166, 0x16A, 0x16E, 0x172, 0x176, 0x17A, 0x17D, 0x181, 0x185, 0x189, 0x18D, 0x191, 0x195, 0x19A, 0x19E, 0x1A2, 0x1A6, 0x1AA, 0x1AE, 0x1B2, 0x1B7, 0x1BB, 0x1BF, 0x1C3, 0x1C8, 0x1CC, 0x1D0, 0x1D5, 0x1D9, 0x1DD, 0x1E2, 0x1E6, 0x1EB, 0x1EF, 0x1F3, 0x1F8, 0x1FC, 0x201, 0x205, 0x20A, 0x20F, 0x213, 0x218, 0x21C, 0x221, 0x226, 0x22A, 0x22F, 0x233, 0x238, 0x23D, 0x241, 0x246, 0x24B, 0x250, 0x254, 0x259, 0x25E, 0x263, 0x267, 0x26C, 0x271, 0x276, 0x27B, 0x280, 0x284, 0x289, 0x28E, 0x293, 0x298, 0x29D, 0x2A2, 0x2A6, 0x2AB, 0x2B0, 0x2B5, 0x2BA, 0x2BF, 0x2C4, 0x2C9, 0x2CE, 0x2D3, 0x2D8, 0x2DC, 0x2E1, 0x2E6, 0x2EB, 0x2F0, 0x2F5, 0x2FA, 0x2FF, 0x304, 0x309, 0x30E, 0x313, 0x318, 0x31D, 0x322, 0x326, 0x32B, 0x330, 0x335, 0x33A, 0x33F, 0x344, 0x349, 0x34E, 0x353, 0x357, 0x35C, 0x361, 0x366, 0x36B, 0x370, 0x374, 0x379, 0x37E, 0x383, 0x388, 0x38C, 0x391, 0x396, 0x39B, 0x39F, 0x3A4, 0x3A9, 0x3AD, 0x3B2, 0x3B7, 0x3BB, 0x3C0, 0x3C5, 0x3C9, 0x3CE, 0x3D2, 0x3D7, 0x3DC, 0x3E0, 0x3E5, 0x3E9, 0x3ED, 0x3F2, 0x3F6, 0x3FB, 0x3FF, 0x403, 0x408, 0x40C, 0x410, 0x415, 0x419, 0x41D, 0x421, 0x425, 0x42A, 0x42E, 0x432, 0x436, 0x43A, 0x43E, 0x442, 0x446, 0x44A, 0x44E, 0x452, 0x455, 0x459, 0x45D, 0x461, 0x465, 0x468, 0x46C, 0x470, 0x473, 0x477, 0x47A, 0x47E, 0x481, 0x485, 0x488, 0x48C, 0x48F, 0x492, 0x496, 0x499, 0x49C, 0x49F, 0x4A2, 0x4A6, 0x4A9, 0x4AC, 0x4AF, 0x4B2, 0x4B5, 0x4B7, 0x4BA, 0x4BD, 0x4C0, 0x4C3, 0x4C5, 0x4C8, 0x4CB, 0x4CD, 0x4D0, 0x4D2, 0x4D5, 0x4D7, 0x4D9, 0x4DC, 0x4DE, 0x4E0, 0x4E3, 0x4E5, 0x4E7, 0x4E9, 0x4EB, 0x4ED, 0x4EF, 0x4F1, 0x4F3, 0x4F5, 0x4F6, 0x4F8, 0x4FA, 0x4FB, 0x4FD, 0x4FF, 0x500, 0x502, 0x503, 0x504, 0x506, 0x507, 0x508, 0x50A, 0x50B, 0x50C, 0x50D, 0x50E, 0x50F, 0x510, 0x511, 0x511, 0x512, 0x513, 0x514, 0x514, 0x515, 0x516, 0x516, 0x517, 0x517, 0x517, 0x518, 0x518, 0x518, 0x518, 0x518, 0x519, 0x519 }; /*========== DEFINES ==========*/ #undef DEBUG #undef DBG_KEY #undef DBG_ENV #undef DBG_PMOD #undef DBG_BRR #undef DBG_ECHO #undef DBG_INTRP #undef NO_PMOD #undef NO_ECHO #define CPU_RATE ( 1024000 ) #define SAMP_FREQ ( 32000 ) /*========== VARIABLES ==========*/ static int keyed_on; static int keys; /* 8-bits for 8 voices */ static voice_state_type voice_state[ 8 ]; /* Noise stuff */ static int noise_cnt; static int noise_lev; /* These are for the FIR echo filter */ #ifndef NO_ECHO static short FIRlbuf[ 8 ]; static short FIRrbuf[ 8 ]; static int FIRptr; static int echo_ptr; #endif /*========== CONSTANTS ==========*/ /* Original SPC DSP took samples 32000 times a second, which is once every (1024000/32000 = 32) cycles. */ #ifdef UNUSED_DEFINITION static const int TS_CYC = CPU_RATE / SAMP_FREQ; #endif /* Ptrs to Gaussian table */ static const int *const G1 = &gauss[ 256 ]; static const int *const G2 = &gauss[ 512 ]; static const int *const G3 = &gauss[ 255 ]; static const int *const G4 = &gauss[ -1 ]; static const int mask = 0xFF; /* This table is for envelope timing. It represents the number of counts that should be subtracted from the counter each sample period (32kHz). The counter starts at 30720 (0x7800). */ static const int CNT_INIT = 0x7800; static const int ENVCNT[ 0x20 ] = { 0x0000, 0x000F, 0x0014, 0x0018, 0x001E, 0x0028, 0x0030, 0x003C, 0x0050, 0x0060, 0x0078, 0x00A0, 0x00C0, 0x00F0, 0x0140, 0x0180, 0x01E0, 0x0280, 0x0300, 0x03C0, 0x0500, 0x0600, 0x0780, 0x0A00, 0x0C00, 0x0F00, 0x1400, 0x1800, 0x1E00, 0x2800, 0x3C00, 0x7800 }; /*========== MACROS ==========*/ /* Make reading the ADSR code easier */ #define SL( v ) ( DSPregs[ ( ( v ) << 4 ) + 6 ] >> 5 ) /* Returns SUSTAIN level */ #define SR( v ) ( DSPregs[ ( ( v ) << 4 ) + 6 ] & 0x1F ) /* Returns SUSTAIN rate */ /* Handle endianness */ #ifndef LSB_FIRST #define LEtoME16( x ) \ ( ( ( ( x ) >> 8 ) & 0xFF ) | ( ( ( x ) << 8 ) & 0xFF00 ) ) #define MEtoLE16( x ) \ ( ( ( ( x ) >> 8 ) & 0xFF ) | ( ( ( x ) << 8 ) & 0xFF00 ) ) #else #define LEtoME16( x ) ( x ) #define MEtoLE16( x ) ( x ) #endif /*========== PROCEDURES ==========*/ static int AdvanceEnvelope /* Run envelope step & retn ENVX*/ ( int v /* Voice to process envelope for*/ ); /* Privately shared functions (for internal library use only) */ /***** DSP_Reset *****/ void DSP_Reset /* Reset emulated DSP */ ( void ) { int i; #ifdef DEBUG fprintf( stderr,"DSP_Reset\n" ); #endif for( i = 0; i < 8; i++ ) { #ifndef NO_ECHO FIRlbuf[ i ] = 0; FIRrbuf[ i ] = 0; #endif voice_state[ i ].on_cnt = 0; } #ifndef NO_ECHO FIRptr = 0; echo_ptr = 0; #endif keys = 0; keyed_on = 0; noise_cnt = 0; noise_lev = 0x4000; DSPregs[ 0x6C ] |= 0xE0; DSPregs[ 0x4C ] = 0; DSPregs[ 0x5C ] = 0; } /* DSP_Reset() */ /***** DSP_Update *****/ void DSP_Update /* Mix one sample of audio */ ( short * sound_ptr /* Pointer to mix audio into */ ) { int V; #ifndef NO_ECHO int echo_base; #endif int echol; int echor; int envx; int m; int outl; int outr; signed long outx; /* Smpl height (must be signed) */ src_dir_type * sd; int v; int vl; voice_state_type * vp; int vr; sd = ( src_dir_type * )&spc_ram[ ( int )DSPregs[ 0x5D ] << 8 ]; /* Check for reset */ if( DSPregs[ 0x6C ] & 0x80 ) { DSP_Reset(); } /* Here we check for keys on/off. Docs say that successive writes to KON/KOF must be separated by at least 2 Ts periods or risk being neglected. Therefore DSP only looks at these during an update, and not at the time of the write. Only need to do this once however, since the regs haven't changed over the whole period we need to catch up with. */ #ifdef DBG_KEY DSPregs[ 0x4C ] &= mask; #endif /* Keying on a voice resets that bit in ENDX */ DSPregs[ 0x7C ] &= ~DSPregs[ 0x4C ]; /* Question: what is the expected behavior when pitch modulation is enabled on voice 0? Jurassic Park 2 does this. For now, using outx of zero for first voice. */ outx = 0; /* Same table for noise and envelope */ noise_cnt -= ENVCNT[ DSPregs[ 0x6C ] & 0x1F ]; if( noise_cnt <= 0 ) { noise_cnt = CNT_INIT; noise_lev = ( ( ( noise_lev << 13 ) ^ ( noise_lev << 14 ) ) & 0x4000 ) | ( noise_lev >> 1 ); } outl = 0; outr = 0; echol = 0; echor = 0; for( v = 0, m = 1, V = 0; v < 8; v++, V += 16, m <<= 1 ) { vp = &voice_state[ v ]; if( vp->on_cnt && ( --vp->on_cnt == 0 ) ) { /* Voice was keyed on */ keys |= m; keyed_on |= m; vl = DSPregs[ ( v<<4 ) + 4 ]; vp->samp_id = *( UINT32 * )&sd[ vl ]; vp->mem_ptr = LEtoME16( sd[ vl ].vptr ); #ifdef DBG_KEY fprintf( stderr, "Keying on voice %d, samp=0x%04X (0x%02X)\n", v, vp->mem_ptr, vl ); #endif vp->header_cnt = 0; vp->half = 0; vp->envx = 0; vp->end = 0; vp->sampptr = 0; vp->mixfrac = 3 * 4096; /* NOTE: Real SNES does *not* appear to initialize the envelope counter to anything in particular. The first cycle always seems to come at a random time sooner than expected; as yet, I have been unable to find any pattern. I doubt it will matter though, so we'll go ahead and do the full time for now. */ vp->envcnt = CNT_INIT; vp->envstate = ATTACK; } if( DSPregs[ 0x4C ] & m & ~DSPregs[ 0x5C ] ) { /* Voice doesn't come on if key off is set */ DSPregs[ 0x4C ] &= ~m; vp->on_cnt = 8; #ifdef DBG_KEY fprintf( stderr, "Key on set for voice %d\n", v ); #endif } if( keys & DSPregs[ 0x5C ] & m ) { /* Voice was keyed off */ vp->envstate = RELEASE; vp->on_cnt = 0; #ifdef DBG_KEY fprintf( stderr, "Keying off voice %d\n", v ); #endif } if( !( keys & m & mask ) || ( ( envx = AdvanceEnvelope( v ) ) < 0 ) ) { DSPregs[ V + 8 ] = 0; DSPregs[ V + 9 ] = 0; outx = 0; continue; } vp->pitch = LEtoME16( *( ( UINT16 * )&DSPregs[ V + 2 ] ) ) & 0x3FFF; #ifndef NO_PMOD /* Pitch mod uses OUTX from last voice for this one. Luckily we haven't modified OUTX since it was used for last voice. */ if(DSPregs[ 0x2D ] & m ) { #ifdef DBG_PMOD fprintf( stderr, "Pitch Modulating voice %d, outx=%ld, old pitch=%d, ", v, outx, vp->pitch ); #endif vp->pitch = ( vp->pitch * ( outx + 32768 ) ) >> 15; } #endif #ifdef DBG_PMOD fprintf( stderr, "pitch=%d\n", vp->pitch ); #endif for( ; vp->mixfrac >= 0; vp->mixfrac -= 4096 ) { /* This part performs the BRR decode 'on-the-fly'. This is more correct than the old way, which could be fooled if the data and/or the loop point changed while the sample was playing, or if the BRR decode didn't produce the same result every loop because of the filters. The event interface still has no chance of keeping up with those kinds of tricks, though. */ if( !vp->header_cnt ) { if( vp->end & 1 ) { /* Docs say ENDX bit is set when decode of block with source end flag set is done. Does this apply to looping samples? Some info I've seen suggests yes. */ DSPregs[ 0x7C ] |= m; if( vp->end & 2 ) { vp->mem_ptr = LEtoME16( sd[ DSPregs[ V + 4 ] ].lptr ); #ifdef DBG_BRR fprintf( stderr, "BRR looping to 0x%04X\n", vp->mem_ptr ); #endif } else { #ifdef DBG_KEY fprintf( stderr, "BRR decode end, voice %d\n", v ); #endif keys &= ~m; DSPregs[ V + 8 ] = 0; vp->envx = 0; while( vp->mixfrac >= 0 ) { vp->sampbuf[ vp->sampptr ] = 0; outx = 0; vp->sampptr = ( vp->sampptr + 1 ) & 3; vp->mixfrac -= 4096; } break; } } vp->header_cnt = 8; vl = ( UINT8 )spc_ram[ vp->mem_ptr++ ]; vp->range = vl >> 4; vp->end = vl & 3; vp->filter = ( vl & 12 ) >> 2; #ifdef DBG_BRR fprintf( stderr, "V%d: header read, range=%d, end=%d, filter=%d\n", v, vp->range, vp->end, vp->filter ); #endif } if( vp->half == 0 ) { vp->half = 1; outx = ( ( signed char )spc_ram[ vp->mem_ptr ] ) >> 4; } else { vp->half = 0; /* Funkiness to get 4-bit signed to carry through */ outx = ( signed char )( spc_ram[ vp->mem_ptr++ ] << 4 ); outx >>= 4; vp->header_cnt--; } #ifdef DBG_BRR fprintf( stderr, "V%d: nybble=%X, ptr=%04X, smp1=%d, smp2=%d\n", v, outx & 0xF, vp->mem_ptr, vp->smp1, vp->smp2 ); #endif /* For invalid ranges (D,E,F): if the nybble is negative, the result is F000. If positive, 0000. Nothing else like previous range, etc. seems to have any effect. If range is valid, do the shift normally. Note these are both shifted right once to do the filters properly, but the output will be shifted back again at the end. */ if( vp->range <= 0xC ) { outx = ( outx << vp->range ) >> 1; } else { outx &= ~0x7FF; #ifdef DBG_BRR fprintf( stderr, "V%d: invalid range! (%X)\n", v, vp->range ); #endif } #ifdef DBG_BRR fprintf( stderr, "V%d: shifted delta=%04X\n", v, ( UINT16 )outx ); #endif switch( vp->filter ) { case 0: break; case 1: outx += ( vp->smp1 >> 1 ) + ( ( -vp->smp1 ) >> 5 ); break; case 2: outx += vp->smp1 + ( ( -( vp->smp1 + ( vp->smp1 >> 1 ) ) ) >> 5 ) - ( vp->smp2 >> 1 ) + ( vp->smp2 >> 5 ); break; case 3: outx += vp->smp1 + ( ( -( vp->smp1 + ( vp->smp1 << 2 ) + ( vp->smp1 << 3 ) ) ) >> 7 ) - ( vp->smp2 >> 1 ) + ( ( vp->smp2 + ( vp->smp2 >> 1 ) ) >> 4 ); break; } if( outx < ( signed short )0x8000 ) { outx = ( signed short )0x8000; } else if( outx > ( signed short )0x7FFF ) { outx = ( signed short )0x7FFF; } #ifdef DBG_BRR fprintf( stderr, "V%d: filter + delta=%04X\n", v, ( UINT16 )outx ); #endif vp->smp2 = ( signed short )vp->smp1; vp->smp1 = ( signed short )( outx << 1 ); vp->sampbuf[ vp->sampptr ] = vp->smp1; #ifdef DBG_BRR fprintf( stderr, "V%d: final output: %04X\n", v, vp->sampbuf[ vp->sampptr ] ); #endif vp->sampptr = ( vp->sampptr + 1 ) & 3; } if(DSPregs[ 0x3D ] & m ) { #ifdef DBG_PMOD fprintf( stderr, "Noise enabled, voice %d\n", v ); #endif outx = ( signed short )( noise_lev << 1 ); } else { /* Perform 4-Point Gaussian interpolation. Take an approximation of a Gaussian bell-curve, and move it through the sample data at a rate determined by the pitch. The sample output at any given time is the sum of the products of each input sample point with the value of the bell-curve corresponding to that point. */ vl = vp->mixfrac >> 4; vr = ( ( G4[ -vl ] * vp->sampbuf[ vp->sampptr ] ) >> 11 ) & ~1; vr += ( ( G3[ -vl ] * vp->sampbuf[ ( vp->sampptr + 1 ) & 3 ] ) >> 11 ) & ~1; vr += ( ( G2[ vl ] * vp->sampbuf[ ( vp->sampptr + 2 ) & 3 ] ) >> 11 ) & ~1; /* This is to do the wrapping properly. Based on my tests with the SNES, it appears clipping is done only if it is the fourth addition that would cause a wrap. If it has already wrapped before the fourth addition, it is not clipped. */ vr = ( signed short )vr; vr += ( ( G1[ vl ] * vp->sampbuf[ ( vp->sampptr + 3 ) & 3 ] ) >> 11 ) & ~1; if( vr > 32767 ) { vr = 32767; } else if( vr < -32768 ) { vr = -32768; } outx = ( signed short )vr; #ifdef DBG_INTRP fprintf( stderr, "V%d: mixfrac=%d: [%d]*%d + [%d]*%d + [%d]*%d + [%d]*%d = %d\n", v, vl, G1[ vl ], vp->sampbuf[ ( vp->sampptr + 3 ) & 3 ], G2[ vl ], vp->sampbuf[ ( vp->sampptr + 2 ) & 3 ], G3[ -vl ], vp->sampbuf[ ( vp->sampptr + 1 ) & 3 ], G4[ -vl ], vp->sampbuf[ vp->sampptr ], outx ); #endif } /* Advance the sample position for next update. */ vp->mixfrac += vp->pitch; outx = ( ( outx * envx ) >> 11 ) & ~1; DSPregs[ V + 9 ] = outx >> 8; vl = ( ( ( int )( signed char )DSPregs[ V ] ) * outx ) >> 7; vr = ( ( ( int )( signed char )DSPregs[ V + 1 ] ) * outx ) >> 7; outl += vl; outr += vr; if( DSPregs[ 0x4D ] & m ) { echol += vl; echor += vr; } } outl = ( outl * ( signed char )DSPregs[ 0x0C ] ) >> 7; outr = ( outr * ( signed char )DSPregs[ 0x1C ] ) >> 7; #ifndef NO_ECHO /* Perform echo. First, read mem at current location, and put those samples into the FIR filter queue. */ #ifdef DBG_ECHO fprintf( stderr, "Echo delay=%dms, feedback=%d%%\n", DSPregs[ 0x7D ] * 16, ( ( signed char )DSPregs[ 0x0D ] * 100 ) / 0x7F ); #endif echo_base = ( ( DSPregs[ 0x6D ] << 8 ) + echo_ptr ) & 0xFFFF; FIRlbuf[ FIRptr ] = ( signed short )LEtoME16( *( UINT16 * ) &spc_ram[ echo_base ] ); FIRrbuf[ FIRptr ] = ( signed short )LEtoME16( *( UINT16 * ) &spc_ram[ echo_base + sizeof( short ) ] ); /* Now, evaluate the FIR filter, and add the results into the final output. */ vl = FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x7F ]; vr = FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x7F ]; FIRptr = ( FIRptr + 1 ) & 7; vl += FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x6F ]; vr += FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x6F ]; FIRptr = ( FIRptr + 1 ) & 7; vl += FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x5F ]; vr += FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x5F ]; FIRptr = ( FIRptr + 1 ) & 7; vl += FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x4F ]; vr += FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x4F ]; FIRptr = ( FIRptr + 1 ) & 7; vl += FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x3F ]; vr += FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x3F ]; FIRptr = ( FIRptr + 1 ) & 7; vl += FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x2F ]; vr += FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x2F ]; FIRptr = ( FIRptr + 1 ) & 7; vl += FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x1F ]; vr += FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x1F ]; FIRptr = ( FIRptr + 1 ) & 7; vl += FIRlbuf[ FIRptr ] * ( signed char )DSPregs[ 0x0F ]; vr += FIRrbuf[ FIRptr ] * ( signed char )DSPregs[ 0x0F ]; #ifdef DBG_ECHO fprintf( stderr, "FIR Coefficients: %02X %02X %02X %02X %02X %02X %02X %02X\n", DSPregs[ 0x0F ], DSPregs[ 0x1F ], DSPregs[ 0x2F ], DSPregs[ 0x3F ], DSPregs[ 0x4F ], DSPregs[ 0x5F ], DSPregs[ 0x6F ], DSPregs[ 0x7F ] ); #endif /* FIRptr is left in the position of the oldest sample, the one that will be replaced next update. */ outl += vl * ( signed char )DSPregs[ 0x2C ] >> 14; outr += vr * ( signed char )DSPregs[ 0x3C ] >> 14; if( !( DSPregs[ 0x6C ] & 0x20 ) ) { /* Add the echo feedback back into the original result, and save that into memory for use later. */ echol += vl * ( signed char )DSPregs[ 0x0D ] >> 14; if( echol > 32767 ) { echol = 32767; } else if( echol < -32768 ) { echol = -32768; } echor += vr * ( signed char )DSPregs[ 0x0D ] >> 14; if( echor > 32767 ) { echor = 32767; } else if( echor < -32768 ) { echor = -32768; } #ifdef DBG_ECHO fprintf( stderr, "Echo: Writing %04X,%04X at location %04X\n", ( UINT16 )echol, ( UINT16 )echor, echo_base ); #endif *( UINT16 * )&spc_ram[ echo_base ] = MEtoLE16( ( UINT16 )echol ); *( UINT16 * )&spc_ram[ echo_base + sizeof( short ) ] = MEtoLE16( ( UINT16 )echor ); } echo_ptr += 2 * sizeof( short ); if( echo_ptr >= ( ( DSPregs[ 0x7D ] & 0xF ) << 11 ) ) { echo_ptr = 0; } #endif /* !defined( NO_ECHO ) */ if( sound_ptr ) { if( DSPregs[ 0x6C ] & 0x40 ) { /* MUTE */ #ifdef DEBUG fprintf( stderr, "MUTED!\n" ); #endif *sound_ptr = 0; sound_ptr++; *sound_ptr = 0; sound_ptr++; } else { if( outl > 32767 ) { *sound_ptr = 32767; } else if( outl < -32768 ) { *sound_ptr = -32768; } else { *sound_ptr = outl; } sound_ptr++; if( outr > 32767 ) { *sound_ptr = 32767; } else if( outr < -32768 ) { *sound_ptr = -32768; } else { *sound_ptr = outr; } sound_ptr++; } } } /* DSP_Update() */ /***** AdvanceEnvelope *****/ static int AdvanceEnvelope /* Run envelope step & retn ENVX*/ ( int v /* Voice to process envelope for*/ ) { int envx; int cnt; int adsr1; int t; envx = voice_state[ v ].envx; if( voice_state[ v ].envstate == RELEASE ) { /* Docs: "When in the state of "key off". the "click" sound is prevented by the addition of the fixed value 1/256" WTF??? Alright, I'm going to choose to interpret that this way: When a note is keyed off, start the RELEASE state, which subtracts 1/256th each sample period (32kHz). Note there's no need for a count because it always happens every update. */ envx -= 0x8; /* 0x8 / 0x800 = 1/256th */ if( envx <= 0 ) { envx = 0; keys &= ~( 1 << v ); return -1; } voice_state[ v ].envx = envx; DSPregs[ ( v << 4 ) + 8 ] = envx >> 8; #ifdef DBG_ENV fprintf( stderr, "ENV voice %d: envx=%03X, state=RELEASE\n", v, envx ); #endif return( envx ); } cnt = voice_state[ v ].envcnt; adsr1 = DSPregs[ ( v << 4 ) + 5 ]; if( adsr1 & 0x80 ) { switch( voice_state[ v ].envstate ) { case ATTACK: /* Docs are very confusing. "AR is multiplied by the fixed value 1/64..." I believe it means to add 1/64th to ENVX once every time ATTACK is updated, and that's what I'm going to implement. */ t = adsr1 & 0xF; if( t == 0xF ) { #ifdef DBG_ENV fprintf( stderr, "ENV voice %d: instant attack\n", v ); #endif envx += 0x400; } else { cnt -= ENVCNT[ ( t << 1 ) + 1 ]; if( cnt > 0 ) { break; } envx += 0x20; /* 0x020 / 0x800 = 1/64 */ cnt = CNT_INIT; } if( envx > 0x7FF ) { envx = 0x7FF; voice_state[ v ].envstate = DECAY; } #ifdef DBG_ENV fprintf( stderr, "ENV voice %d: envx=%03X, state=ATTACK\n", v, envx ); #endif voice_state[ v ].envx = envx; break; case DECAY: /* Docs: "DR... [is multiplied] by the fixed value 1-1/256." Well, at least that makes some sense. Multiplying ENVX by 255/256 every time DECAY is updated. */ cnt -= ENVCNT[ ( ( adsr1 >> 3 ) & 0xE ) + 0x10 ]; if( cnt <= 0 ) { cnt = CNT_INIT; envx -= ( ( envx - 1 ) >> 8 ) + 1; voice_state[ v ].envx = envx; } if( envx <= 0x100 * ( SL( v ) + 1 ) ) { voice_state[ v ].envstate = SUSTAIN; } #ifdef DBG_ENV fprintf( stderr, "ENV voice %d: envx=%03X, state=DECAY\n", v, envx ); #endif break; case SUSTAIN: /* Docs: "SR [is multiplied] by the fixed value 1-1/256." Multiplying ENVX by 255/256 every time SUSTAIN is updated. */ #ifdef DBG_ENV if( ENVCNT[ SR( v ) ] == 0 ) { fprintf( stderr, "ENV voice %d: envx=%03X, state=SUSTAIN, zero rate\n", v, envx ); } #endif cnt -= ENVCNT[ SR( v ) ]; if( cnt > 0 ) { break; } cnt = CNT_INIT; envx -= ( ( envx - 1 ) >> 8 ) + 1; #ifdef DBG_ENV fprintf( stderr, "ENV voice %d: envx=%03X, state=SUSTAIN\n", v, envx ); #endif voice_state[ v ].envx = envx; /* Note: no way out of this state except by explicit KEY OFF (or switch to GAIN). */ break; case RELEASE: /* Handled earlier to prevent GAIN mode from stopping KEY OFF events */ break; } } else { /* GAIN mode is set Note: if the game switches between ADSR and GAIN modes partway through, should the count be reset, or should it continue from where it was? Does the DSP actually watch for that bit to change, or does it just go along with whatever it sees when it performs the update? I'm going to assume the latter and not update the count, unless I see a game that obviously wants the other behavior. The effect would be pretty subtle, in any case. */ t = DSPregs[ ( v << 4 ) + 7 ]; if( t < 0x80 ) { envx = t << 4; voice_state[ v ].envx = envx; #ifdef DBG_ENV fprintf( stderr, "ENV voice %d: envx=%03X, state=DIRECT\n", v, envx ); #endif } else { switch( t >> 5 ) { case 4: /* Docs: "Decrease (linear): Subtraction of the fixed value 1/64." */ cnt -= ENVCNT[ t & 0x1F ]; if( cnt > 0 ) { break; } cnt = CNT_INIT; envx -= 0x020; /* 0x020 / 0x800 = 1/64th */ if( envx < 0 ) { envx = 0; } #ifdef DBG_ENV fprintf( stderr, "ENV voice %d: envx=%03X, state=DECREASE\n", v, envx ); #endif voice_state[ v ].envx = envx; break; case 5: /* Docs: "Drecrease <sic> (exponential): Multiplication by the fixed value 1-1/256." */ cnt -= ENVCNT[ t & 0x1F ]; if( cnt > 0 ) { break; } cnt = CNT_INIT; envx -= ( ( envx - 1 ) >> 8 ) + 1; #ifdef DBG_ENV fprintf( stderr, "ENV voice %d: envx=%03X, state=EXP\n", v, envx ); #endif voice_state[ v ].envx = envx; break; case 6: /* Docs: "Increase (linear): Addition of the fixed value 1/64." */ cnt -= ENVCNT[ t & 0x1F ]; if( cnt > 0 ) { break; } cnt = CNT_INIT; envx += 0x020; /* 0x020 / 0x800 = 1/64th */ if( envx > 0x7FF ) { envx = 0x7FF; } #ifdef DBG_ENV fprintf( stderr, "ENV voice %d: envx=%03X, state=INCREASE\n", v, envx ); #endif voice_state[ v ].envx = envx; break; case 7: /* Docs: "Increase (bent line): Addition of the constant 1/64 up to .75 of the constaint <sic> 1/256 from .75 to 1." */ cnt -= ENVCNT[ t & 0x1F ]; if( cnt > 0 ) { break; } cnt = CNT_INIT; if( envx < 0x600 ) /* 0x600 / 0x800 = .75 */ { envx += 0x020; /* 0x020 / 0x800 = 1/64 */ } else { envx += 0x008; /* 0x008 / 0x800 = 1/256 */ } if( envx > 0x7FF ) { envx=0x7FF; } #ifdef DBG_ENV fprintf( stderr, "ENV voice %d: envx=%03X, state=INCREASE\n", v, envx ); #endif voice_state[ v ].envx = envx; break; } } } voice_state[ v ].envcnt = cnt; DSPregs[ ( v << 4 ) + 8 ] = envx >> 4; return( envx ); } /* AdvanceEnvelope() */ static TIMER_CALLBACK( snes_spc_timer ) { int which = param; timers[which].counter++; if( timers[which].counter >= spc_ram[0xfa + which] ) // minus = { timers[which].counter = 0; spc_ram[0xfd + which]++; spc_ram[0xfd + which]&= 0xf; } } CUSTOM_START( snes_sh_start ) { running_machine *machine = device->machine; UINT8 ii; /* put IPL image at the top of RAM */ memcpy(snes_ipl_region, memory_region(machine, "user5"), 64); /* default to ROM visible */ spc_ram[0xf1] = 0x80; /* Sort out the ports */ for( ii = 0; ii < 4; ii++ ) { spc_port_in[ii] = 0; spc_port_out[ii] = 0; } channel = stream_create( device, 0, 2, 32000, NULL, snes_sh_update ); /* Initialize the timers */ timers[0].timer = timer_alloc(machine, snes_spc_timer , NULL); timer_adjust_periodic( timers[0].timer, ATTOTIME_IN_HZ(8000), 0, ATTOTIME_IN_HZ(8000) ); timer_enable( timers[0].timer, 0 ); timers[1].timer = timer_alloc(machine, snes_spc_timer , NULL); timer_adjust_periodic( timers[1].timer, ATTOTIME_IN_HZ(8000), 1, ATTOTIME_IN_HZ(8000) ); timer_enable( timers[1].timer, 0 ); timers[2].timer = timer_alloc(machine, snes_spc_timer , NULL); timer_adjust_periodic( timers[2].timer, ATTOTIME_IN_HZ(64000), 2, ATTOTIME_IN_HZ(64000) ); timer_enable( timers[2].timer, 0 ); DSP_Reset(); return auto_malloc(1); } STREAM_UPDATE( snes_sh_update ) { int i; short mix[2]; for (i = 0; i < samples; i++) { mix[0] = mix[1] = 0; DSP_Update(mix); /* Update the buffers */ outputs[0][i] = (stream_sample_t)mix[0]; outputs[1][i] = (stream_sample_t)mix[1]; } } /*************************** * I/O for DSP * ***************************/ static READ8_HANDLER( snes_dsp_io_r ) { stream_update(channel); #ifdef NO_ENVX if( 8 == ( SPCRAM[ 0xF2 ] & 0xF ) ) { DSPregs[ SPCRAM[ 0xF2 ] ] = 0; } #endif return DSPregs[offset & 0x7f]; } static WRITE8_HANDLER( snes_dsp_io_w ) { stream_update(channel); if( 0x7C == offset ) { DSP_WRITE_7C(data); } else { DSPregs[ offset ] = data; } } /*************************** * I/O for SPC700 * ***************************/ READ8_HANDLER( spc_io_r ) { switch( offset ) /* Offset is from 0x00f0 */ { case 0x2: /* Register address */ return spc_ram[0xf2]; case 0x3: /* Register data */ return snes_dsp_io_r( space, spc_ram[0xf2] ); case 0x4: /* Port 0 */ case 0x5: /* Port 1 */ case 0x6: /* Port 2 */ case 0x7: /* Port 3 */ // mame_printf_debug("SPC: rd %02x @ %d, PC=%x\n", spc_port_in[offset-4], offset-4, cpu_get_pc(space->cpu)); return spc_port_in[offset - 4]; case 0xA: /* Timer 0 */ case 0xB: /* Timer 1 */ case 0xC: /* Timer 2 */ break; case 0xD: /* Counter 0 */ case 0xE: /* Counter 1 */ case 0xF: /* Counter 2 */ { UINT8 value = spc_ram[0xf0 + offset] & 0xf; spc_ram[0xf0 + offset] = 0; return value; } } return 0xff; } WRITE8_HANDLER( spc_io_w ) { switch( offset ) /* Offset is from 0x00f0 */ { case 0x1: /* Control */ if( data & 0x1 && !timers[0].enabled ) { timers[0].counter = 0; spc_ram[0xfd] = 0; } if( data & 0x2 && !timers[1].enabled ) { timers[1].counter = 0; spc_ram[0xfe] = 0; } if( data & 0x4 && !timers[2].enabled ) { timers[2].counter = 0; spc_ram[0xff] = 0; } timers[0].enabled = data & 0x1; timer_enable( timers[0].timer, timers[0].enabled ); timers[1].enabled = (data & 0x2) >> 1; timer_enable( timers[1].timer, timers[1].enabled ); timers[2].enabled = (data & 0x4) >> 2; timer_enable( timers[2].timer, timers[2].enabled ); if( data & 0x10 ) { spc_port_in[0] = 0; spc_port_in[1] = 0; } if( data & 0x20 ) { spc_port_in[2] = 0; spc_port_in[3] = 0; } if ((data & 0x80) != (spc_ram[0xf1] & 0x80)) { if (data & 0x80) { memcpy(snes_ipl_region, memory_region(space->machine, "user5"), 64); } else { memcpy(snes_ipl_region, &spc_ram[0xffc0], 64); } } break; case 0x2: /* Register address */ break; case 0x3: /* Register data */ snes_dsp_io_w( space, spc_ram[0xf2], data ); break; case 0x4: /* Port 0 */ case 0x5: /* Port 1 */ case 0x6: /* Port 2 */ case 0x7: /* Port 3 */ // mame_printf_debug("SPC: %02x to APU @ %d (PC=%x)\n", data, offset&3, cpu_get_pc(space->cpu)); spc_port_out[offset - 4] = data; cpuexec_boost_interleave(space->machine, attotime_zero, ATTOTIME_IN_USEC(20)); break; case 0xA: /* Timer 0 */ case 0xB: /* Timer 1 */ case 0xC: /* Timer 2 */ if (data == 0) data = 255; break; case 0xD: /* Counter 0 */ case 0xE: /* Counter 1 */ case 0xF: /* Counter 2 */ return; } spc_ram[0xf0 + offset] = data; } READ8_HANDLER( spc_ram_r ) { return spc_ram[offset]; } WRITE8_HANDLER( spc_ram_w ) { spc_ram[offset] = data; // if RAM is mapped in, mirror accordingly if ((!(spc_ram[0xf1] & 0x80)) && (offset >= 0xffc0)) { snes_ipl_region[offset-0xffc0] = data; } } READ8_HANDLER( spc_ipl_r ) { return snes_ipl_region[offset]; }
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