718 lines
18 KiB
C++
718 lines
18 KiB
C++
#include "nes_dmc.h"
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#include "nes_apu.h"
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#include "common.h"
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#include <assert.h>
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#include <cstdlib>
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namespace xgm
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{
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const unsigned int NES_DMC::wavlen_table[2][16] = {
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{ // NTSC
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4, 8, 16, 32, 64, 96, 128, 160, 202, 254, 380, 508, 762, 1016, 2034, 4068
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},
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{ // PAL
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4, 8, 14, 30, 60, 88, 118, 148, 188, 236, 354, 472, 708, 944, 1890, 3778
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}};
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const unsigned int NES_DMC::freq_table[2][16] = {
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{ // NTSC
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428, 380, 340, 320, 286, 254, 226, 214, 190, 160, 142, 128, 106, 84, 72, 54
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},
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{ // PAL
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398, 354, 316, 298, 276, 236, 210, 198, 176, 148, 132, 118, 98, 78, 66, 50
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}};
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const unsigned int BITREVERSE[256] = {
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0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, 0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
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0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8, 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8,
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0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4, 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
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0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC, 0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
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0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2, 0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2,
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0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA, 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
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0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6, 0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6,
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0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE, 0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
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0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1, 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
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0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9, 0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9,
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0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5, 0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5,
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0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED, 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
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0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3, 0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3,
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0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB, 0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
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0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7, 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
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0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF, 0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF,
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};
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NES_DMC::NES_DMC () : GETA_BITS (20)
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{
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SetClock (DEFAULT_CLOCK);
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SetRate (DEFAULT_RATE);
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SetPal (false);
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option[OPT_ENABLE_4011] = 1;
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option[OPT_ENABLE_PNOISE] = 1;
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option[OPT_UNMUTE_ON_RESET] = 1;
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option[OPT_DPCM_ANTI_CLICK] = 0;
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option[OPT_NONLINEAR_MIXER] = 1;
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option[OPT_RANDOMIZE_NOISE] = 1;
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option[OPT_RANDOMIZE_TRI] = 1;
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option[OPT_TRI_MUTE] = 1;
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option[OPT_DPCM_REVERSE] = 0;
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tnd_table[0][0][0][0] = 0;
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tnd_table[1][0][0][0] = 0;
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apu = NULL;
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frame_sequence_count = 0;
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frame_sequence_length = 7458;
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frame_sequence_steps = 4;
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for(int c=0;c<2;++c)
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for(int t=0;t<3;++t)
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sm[c][t] = 128;
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}
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NES_DMC::~NES_DMC ()
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{
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}
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void NES_DMC::SetStereoMix(int trk, short mixl, short mixr)
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{
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if (trk < 0) return;
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if (trk > 2) return;
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sm[0][trk] = mixl;
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sm[1][trk] = mixr;
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}
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void NES_DMC::FrameSequence(int s)
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{
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//DEBUG_OUT("FrameSequence: %d¥n",s);
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if (s > 3) return; // no operation in step 4
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if (apu)
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{
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apu->FrameSequence(s);
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}
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if (s == 0 && (frame_sequence_steps == 4))
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{
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if (frame_irq_enable) frame_irq = true;
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}
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// 240hz clock
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{
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// triangle linear counter
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if (linear_counter_halt)
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{
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linear_counter = linear_counter_reload;
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}
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else
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{
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if (linear_counter > 0) --linear_counter;
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}
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if (!linear_counter_control)
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{
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linear_counter_halt = false;
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}
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// noise envelope
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bool divider = false;
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if (envelope_write)
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{
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envelope_write = false;
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envelope_counter = 15;
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envelope_div = 0;
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}
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else
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{
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++envelope_div;
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if (envelope_div > envelope_div_period)
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{
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divider = true;
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envelope_div = 0;
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}
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}
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if (divider)
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{
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if (envelope_loop && envelope_counter == 0)
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envelope_counter = 15;
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else if (envelope_counter > 0)
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--envelope_counter;
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}
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}
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// 120hz clock
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if ((s&1) == 0)
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{
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// triangle length counter
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if (!linear_counter_control && (length_counter[0] > 0))
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--length_counter[0];
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// noise length counter
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if (!envelope_loop && (length_counter[1] > 0))
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--length_counter[1];
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}
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}
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// 三角波チャンネルの計算 戻り値は0-15
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unsigned int NES_DMC::calc_tri (unsigned int clocks)
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{
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static unsigned int tritbl[32] =
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{
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15,14,13,12,11,10, 9, 8,
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7, 6, 5, 4, 3, 2, 1, 0,
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0, 1, 2, 3, 4, 5, 6, 7,
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8, 9,10,11,12,13,14,15,
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};
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if (linear_counter > 0 && length_counter[0] > 0
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&& (!option[OPT_TRI_MUTE] || tri_freq > 0))
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{
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counter[0] -= clocks;
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while (counter[0] < 0)
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{
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tphase = (tphase + 1) & 31;
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counter[0] += (tri_freq + 1);
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}
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}
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unsigned int ret = tritbl[tphase];
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return ret;
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}
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// ノイズチャンネルの計算 戻り値は0-127
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// 低サンプリングレートで合成するとエイリアスノイズが激しいので
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// ノイズだけはこの関数内で高クロック合成し、簡易なサンプリングレート
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// 変換を行っている。
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unsigned int NES_DMC::calc_noise(unsigned int clocks)
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{
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unsigned int env = envelope_disable ? noise_volume : envelope_counter;
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if (length_counter[1] < 1) env = 0;
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unsigned int last = (noise & 0x4000) ? 0 : env;
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if (clocks < 1) return last;
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// simple anti-aliasing (noise requires it, even when oversampling is off)
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unsigned int count = 0;
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unsigned int accum = counter[1] * last; // samples pending from previous calc
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unsigned int accum_clocks = counter[1];
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#ifdef _DEBUG
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int start_clocks = counter[1];
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#endif
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if (counter[1] < 0) // only happens on startup when using the randomize noise option
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{
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accum = 0;
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accum_clocks = 0;
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}
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counter[1] -= clocks;
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assert (nfreq > 0); // prevent infinite loop
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while (counter[1] < 0)
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{
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// tick the noise generator
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unsigned int feedback = (noise&1) ^ ((noise&noise_tap)?1:0);
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noise = (noise>>1) | (feedback<<14);
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last = (noise & 0x4000) ? 0 : env;
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accum += (last * nfreq);
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counter[1] += nfreq;
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++count;
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accum_clocks += nfreq;
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}
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if (count < 1) // no change over interval, don't anti-alias
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{
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return last;
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}
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accum -= (last * counter[1]); // remove these samples which belong in the next calc
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accum_clocks -= counter[1];
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#ifdef _DEBUG
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if (start_clocks >= 0) assert(accum_clocks == clocks); // these should be equal
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#endif
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unsigned int average = accum / accum_clocks;
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assert(average <= 15); // above this would indicate overflow
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return average;
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}
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// Tick the DMC for the number of clocks, and return output counter;
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unsigned int NES_DMC::calc_dmc (unsigned int clocks)
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{
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counter[2] -= clocks;
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assert (dfreq > 0); // prevent infinite loop
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while (counter[2] < 0)
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{
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counter[2] += dfreq;
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if ( data > 0x100 ) // data = 0x100 when shift register is empty
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{
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if (!empty)
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{
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if ((data & 1) && (damp < 63))
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damp++;
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else if (!(data & 1) && (0 < damp))
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damp--;
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}
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data >>=1;
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}
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if ( data <= 0x100 ) // shift register is empty
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{
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if (dlength > 0)
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{
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memory (daddress, data);
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// (checking for the 3-cycle case would require sub-instruction emulation)
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data &= 0xFF; // read 8 bits
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if (option[OPT_DPCM_REVERSE]) data = BITREVERSE[data];
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data |= 0x10000; // use an extra bit to signal end of data
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empty = false;
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daddress = ((daddress+1)&0xFFFF)|0x8000 ;
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--dlength;
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if (dlength == 0)
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{
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if (mode & 1) // looped DPCM = auto-reload
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{
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daddress = ((adr_reg<<6)|0xC000);
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dlength = (len_reg<<4)+1;
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}
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else if (mode & 2) // IRQ and not looped
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{
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irq = true;
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}
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}
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}
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else
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{
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data = 0x10000; // DMC will do nothing
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empty = true;
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}
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}
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}
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return (damp<<1) + dac_lsb;
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}
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void NES_DMC::TickFrameSequence (unsigned int clocks)
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{
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frame_sequence_count += clocks;
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while (frame_sequence_count > frame_sequence_length)
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{
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FrameSequence(frame_sequence_step);
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frame_sequence_count -= frame_sequence_length;
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++frame_sequence_step;
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if(frame_sequence_step >= frame_sequence_steps)
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frame_sequence_step = 0;
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}
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}
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void NES_DMC::Tick (unsigned int clocks)
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{
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out[0] = calc_tri(clocks);
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out[1] = calc_noise(clocks);
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out[2] = calc_dmc(clocks);
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}
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unsigned int NES_DMC::Render (int b[2])
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{
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out[0] = (mask & 1) ? 0 : out[0];
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out[1] = (mask & 2) ? 0 : out[1];
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out[2] = (mask & 4) ? 0 : out[2];
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int m[3];
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m[0] = tnd_table[0][out[0]][0][0];
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m[1] = tnd_table[0][0][out[1]][0];
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m[2] = tnd_table[0][0][0][out[2]];
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if (option[OPT_NONLINEAR_MIXER])
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{
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int ref = m[0] + m[1] + m[2];
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int voltage = tnd_table[1][out[0]][out[1]][out[2]];
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if (ref)
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{
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for (int i=0; i < 3; ++i)
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m[i] = (m[i] * voltage) / ref;
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}
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else
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{
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for (int i=0; i < 3; ++i)
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m[i] = voltage;
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}
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}
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// anti-click nullifies any 4011 write but preserves nonlinearity
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if (option[OPT_DPCM_ANTI_CLICK])
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{
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if (dmc_pop) // $4011 will cause pop this frame
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{
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// adjust offset to counteract pop
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dmc_pop_offset += dmc_pop_follow - m[2];
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dmc_pop = false;
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// prevent overflow, keep headspace at edges
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const int OFFSET_MAX = (1 << 30) - (4 << 16);
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if (dmc_pop_offset > OFFSET_MAX) dmc_pop_offset = OFFSET_MAX;
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if (dmc_pop_offset < -OFFSET_MAX) dmc_pop_offset = -OFFSET_MAX;
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}
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dmc_pop_follow = m[2]; // remember previous position
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m[2] += dmc_pop_offset; // apply offset
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// TODO implement this in a better way
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// roll off offset (not ideal, but prevents overflow)
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if (dmc_pop_offset > 0) --dmc_pop_offset;
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else if (dmc_pop_offset < 0) ++dmc_pop_offset;
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}
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b[0] = m[0] * sm[0][0];
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b[0] += m[1] * sm[0][1];
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b[0] += m[2] * sm[0][2];
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b[0] >>= 7;
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b[1] = m[0] * sm[1][0];
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b[1] += m[1] * sm[1][1];
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b[1] += m[2] * sm[1][2];
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b[1] >>= 7;
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return 2;
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}
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void NES_DMC::SetClock (double c)
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{
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clock = c;
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}
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void NES_DMC::SetRate (double r)
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{
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rate = (unsigned int)(r?r:DEFAULT_RATE);
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}
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void NES_DMC::SetPal (bool is_pal)
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{
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pal = (is_pal ? 1 : 0);
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// set CPU cycles in frame_sequence
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frame_sequence_length = is_pal ? 8314 : 7458;
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}
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void NES_DMC::SetAPU (NES_APU* apu_)
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{
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apu = apu_;
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}
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// Initializing TRI, NOISE, DPCM mixing table
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void NES_DMC::InitializeTNDTable(double wt, double wn, double wd) {
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// volume adjusted by 0.95 based on empirical measurements
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const double MASTER = 8192.0 * 0.95;
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// truthfully, the nonlinear curve does not appear to match well
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// with my tests. Do more testing of the APU/DMC DAC later.
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// this value keeps the triangle consistent with measured levels,
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// but not necessarily the rest of this APU channel,
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// because of the lack of a good DAC model, currently.
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{ // Linear Mixer
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for(int t=0; t<16 ; t++) {
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for(int n=0; n<16; n++) {
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for(int d=0; d<128; d++) {
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tnd_table[0][t][n][d] = (unsigned int)(MASTER*(3.0*t+2.0*n+d)/208.0);
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}
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}
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}
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}
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{ // Non-Linear Mixer
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tnd_table[1][0][0][0] = 0;
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for(int t=0; t<16 ; t++) {
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for(int n=0; n<16; n++) {
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for(int d=0; d<128; d++) {
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if(t!=0||n!=0||d!=0)
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tnd_table[1][t][n][d] = (unsigned int)((MASTER*159.79)/(100.0+1.0/((double)t/wt+(double)n/wn+(double)d/wd)));
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}
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}
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}
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}
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}
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void NES_DMC::Reset ()
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{
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int i;
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mask = 0;
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InitializeTNDTable(8227,12241,22638);
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counter[0] = 0;
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counter[1] = 0;
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counter[2] = 0;
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tphase = 0;
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nfreq = wavlen_table[0][0];
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dfreq = freq_table[0][0];
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tri_freq = 0;
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linear_counter = 0;
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linear_counter_reload = 0;
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linear_counter_halt = 0;
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linear_counter_control = 0;
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noise_volume = 0;
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noise = 0;
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noise_tap = 0;
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envelope_loop = 0;
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envelope_disable = 0;
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envelope_write = 0;
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envelope_div_period = 0;
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envelope_div = 0;
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envelope_counter = 0;
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enable[0] = 0;
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enable[1] = 0;
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length_counter[0] = 0;
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length_counter[1] = 0;
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frame_irq = false;
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|
frame_irq_enable = false;
|
|
frame_sequence_count = 0;
|
|
frame_sequence_steps = 4;
|
|
frame_sequence_step = 0;
|
|
|
|
for (i = 0; i < 0x0F; i++)
|
|
Write (0x4008 + i, 0);
|
|
Write (0x4017, 0x40);
|
|
|
|
irq = false;
|
|
Write (0x4015, 0x00);
|
|
if (option[OPT_UNMUTE_ON_RESET])
|
|
Write (0x4015, 0x0f);
|
|
|
|
out[0] = out[1] = out[2] = 0;
|
|
damp = 0;
|
|
dmc_pop = false;
|
|
dmc_pop_offset = 0;
|
|
dmc_pop_follow = 0;
|
|
dac_lsb = 0;
|
|
data = 0x100;
|
|
empty = true;
|
|
adr_reg = 0;
|
|
dlength = 0;
|
|
len_reg = 0;
|
|
daddress = 0;
|
|
noise = 1;
|
|
noise_tap = (1<<1);
|
|
|
|
if (option[OPT_RANDOMIZE_NOISE])
|
|
{
|
|
noise |= ::rand();
|
|
counter[1] = -(rand() & 511);
|
|
}
|
|
if (option[OPT_RANDOMIZE_TRI])
|
|
{
|
|
tphase = ::rand() & 31;
|
|
counter[0] = -(rand() & 2047);
|
|
}
|
|
|
|
SetRate(rate);
|
|
}
|
|
|
|
void NES_DMC::SetMemory (std::function<void(unsigned short, unsigned int&)> r)
|
|
{
|
|
memory = r;
|
|
}
|
|
|
|
void NES_DMC::SetOption (int id, int val)
|
|
{
|
|
if(id<OPT_END)
|
|
{
|
|
option[id] = val;
|
|
if(id==OPT_NONLINEAR_MIXER)
|
|
InitializeTNDTable(8227,12241,22638);
|
|
}
|
|
}
|
|
|
|
bool NES_DMC::Write (unsigned int adr, unsigned int val, unsigned int id)
|
|
{
|
|
static const unsigned char length_table[32] = {
|
|
0x0A, 0xFE,
|
|
0x14, 0x02,
|
|
0x28, 0x04,
|
|
0x50, 0x06,
|
|
0xA0, 0x08,
|
|
0x3C, 0x0A,
|
|
0x0E, 0x0C,
|
|
0x1A, 0x0E,
|
|
0x0C, 0x10,
|
|
0x18, 0x12,
|
|
0x30, 0x14,
|
|
0x60, 0x16,
|
|
0xC0, 0x18,
|
|
0x48, 0x1A,
|
|
0x10, 0x1C,
|
|
0x20, 0x1E
|
|
};
|
|
|
|
if (adr == 0x4015)
|
|
{
|
|
enable[0] = (val & 4) ? true : false;
|
|
enable[1] = (val & 8) ? true : false;
|
|
|
|
if (!enable[0])
|
|
{
|
|
length_counter[0] = 0;
|
|
}
|
|
if (!enable[1])
|
|
{
|
|
length_counter[1] = 0;
|
|
}
|
|
|
|
if ((val & 16) && dlength == 0)
|
|
{
|
|
daddress = (0xC000 | (adr_reg << 6));
|
|
dlength = (len_reg << 4) + 1;
|
|
}
|
|
else if (!(val & 16))
|
|
{
|
|
dlength = 0;
|
|
}
|
|
|
|
irq = false;
|
|
|
|
reg[adr-0x4008] = val;
|
|
return true;
|
|
}
|
|
|
|
if (adr == 0x4017)
|
|
{
|
|
//DEBUG_OUT("4017 = %02X¥n", val);
|
|
frame_irq_enable = ((val & 0x40) != 0x40);
|
|
if (frame_irq_enable) frame_irq = false;
|
|
|
|
frame_sequence_count = 0;
|
|
if (val & 0x80)
|
|
{
|
|
frame_sequence_steps = 5;
|
|
frame_sequence_step = 0;
|
|
FrameSequence(frame_sequence_step);
|
|
++frame_sequence_step;
|
|
}
|
|
else
|
|
{
|
|
frame_sequence_steps = 4;
|
|
frame_sequence_step = 1;
|
|
}
|
|
}
|
|
|
|
if (adr<0x4008||0x4013<adr)
|
|
return false;
|
|
|
|
reg[adr-0x4008] = val&0xff;
|
|
|
|
//DEBUG_OUT("$%04X %02X¥n", adr, val);
|
|
|
|
switch (adr)
|
|
{
|
|
|
|
// tri
|
|
|
|
case 0x4008:
|
|
linear_counter_control = (val >> 7) & 1;
|
|
linear_counter_reload = val & 0x7F;
|
|
break;
|
|
|
|
case 0x4009:
|
|
break;
|
|
|
|
case 0x400a:
|
|
tri_freq = val | (tri_freq & 0x700) ;
|
|
break;
|
|
|
|
case 0x400b:
|
|
tri_freq = (tri_freq & 0xff) | ((val & 0x7) << 8) ;
|
|
linear_counter_halt = true;
|
|
if (enable[0])
|
|
{
|
|
length_counter[0] = length_table[(val >> 3) & 0x1f];
|
|
}
|
|
break;
|
|
|
|
// noise
|
|
|
|
case 0x400c:
|
|
noise_volume = val & 15;
|
|
envelope_div_period = val & 15;
|
|
envelope_disable = (val >> 4) & 1;
|
|
envelope_loop = (val >> 5) & 1;
|
|
break;
|
|
|
|
case 0x400d:
|
|
break;
|
|
|
|
case 0x400e:
|
|
if (option[OPT_ENABLE_PNOISE])
|
|
noise_tap = (val & 0x80) ? (1<<6) : (1<<1);
|
|
else
|
|
noise_tap = (1<<1);
|
|
nfreq = wavlen_table[pal][val&15];
|
|
break;
|
|
|
|
case 0x400f:
|
|
if (enable[1])
|
|
{
|
|
length_counter[1] = length_table[(val >> 3) & 0x1f];
|
|
}
|
|
envelope_write = true;
|
|
break;
|
|
|
|
// dmc
|
|
|
|
case 0x4010:
|
|
mode = (val >> 6) & 3;
|
|
if (!(mode & 2))
|
|
{
|
|
irq = false;
|
|
}
|
|
dfreq = freq_table[pal][val&15];
|
|
break;
|
|
|
|
case 0x4011:
|
|
if (option[OPT_ENABLE_4011])
|
|
{
|
|
damp = (val >> 1) & 0x3f;
|
|
dac_lsb = val & 1;
|
|
dmc_pop = true;
|
|
}
|
|
break;
|
|
|
|
case 0x4012:
|
|
adr_reg = val&0xff;
|
|
// ここでdaddressは更新されない
|
|
break;
|
|
|
|
case 0x4013:
|
|
len_reg = val&0xff;
|
|
// ここでlengthは更新されない
|
|
break;
|
|
|
|
default:
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
bool NES_DMC::Read (unsigned int adr, unsigned int & val, unsigned int id)
|
|
{
|
|
if (adr == 0x4015)
|
|
{
|
|
val |=(irq ? 0x80 : 0)
|
|
| (frame_irq ? 0x40 : 0)
|
|
| ((dlength>0) ? 0x10 : 0)
|
|
| (length_counter[1] ? 0x08 : 0)
|
|
| (length_counter[0] ? 0x04 : 0)
|
|
;
|
|
|
|
frame_irq = false;
|
|
return true;
|
|
}
|
|
else if (0x4008<=adr&&adr<=0x4014)
|
|
{
|
|
val |= reg[adr-0x4008];
|
|
return true;
|
|
}
|
|
else
|
|
return false;
|
|
}
|
|
} // namespace
|