512 lines
11 KiB
C
512 lines
11 KiB
C
//
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// NES 2A03
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//
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// Ported from NSFPlay 2.2 to VGMPlay (including C++ -> C conversion)
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// by Valley Bell on 24 September 2013
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// Updated to NSFPlay 2.3 on 26 September 2013
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// (Note: Encoding is UTF-8)
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//#include <assert.h>
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#include <stdlib.h>
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#include <string.h> // for memset()
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#include <stddef.h> // for NULL
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#include "mamedef.h"
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#include "../stdbool.h"
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#include "np_nes_apu.h"
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// Master Clock: 21477272 (NTSC)
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// APU Clock = Master Clock / 12
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#define DEFAULT_CLOCK 1789772.0 // not sure if this shouldn't be 1789772,667 instead
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#define DEFAULT_RATE 44100
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/** Upper half of APU **/
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enum
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{
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OPT_UNMUTE_ON_RESET=0,
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OPT_NONLINEAR_MIXER,
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OPT_PHASE_REFRESH,
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OPT_DUTY_SWAP,
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OPT_END
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};
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enum
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{
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SQR0_MASK = 1,
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SQR1_MASK = 2,
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};
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// Note: For increased speed, I'll inline all of NSFPlay's Counter member functions.
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#define COUNTER_SHIFT 24
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typedef struct _Counter Counter;
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struct _Counter
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{
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double ratio;
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UINT32 val, step;
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};
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#define COUNTER_setcycle(cntr, s) (cntr).step = (UINT32)((cntr).ratio / (s + 1))
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#define COUNTER_iup(cntr) (cntr).val += (cntr).step
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#define COUNTER_value(cntr) ((cntr).val >> COUNTER_SHIFT)
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#define COUNTER_init(cntr, clk, rate) \
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{ \
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(cntr).ratio = (1 << COUNTER_SHIFT) * (1.0 * clk / rate); \
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(cntr).step = (UINT32)((cntr).ratio + 0.5); \
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(cntr).val = 0; \
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}
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typedef struct _NES_APU NES_APU;
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struct _NES_APU
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{
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int option[OPT_END]; // 各種オプション
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int mask;
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INT32 sm[2][2];
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UINT32 gclock;
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UINT8 reg[0x20];
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INT32 out[2];
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double rate, clock;
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INT32 square_table[32]; // nonlinear mixer
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int scounter[2]; // frequency divider
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int sphase[2]; // phase counter
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int duty[2];
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int volume[2];
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int freq[2];
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int sfreq[2];
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bool sweep_enable[2];
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bool sweep_mode[2];
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bool sweep_write[2];
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int sweep_div_period[2];
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int sweep_div[2];
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int sweep_amount[2];
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bool envelope_disable[2];
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bool envelope_loop[2];
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bool envelope_write[2];
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int envelope_div_period[2];
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int envelope_div[2];
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int envelope_counter[2];
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int length_counter[2];
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bool enable[2];
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Counter tick_count;
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UINT32 tick_last;
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};
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static void sweep_sqr(NES_APU* apu, int ch); // calculates target sweep frequency
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static INT32 calc_sqr(NES_APU* apu, int ch, UINT32 clocks);
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static void Tick(NES_APU* apu, UINT32 clocks);
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static void sweep_sqr(NES_APU* apu, int i)
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{
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int shifted = apu->freq[i] >> apu->sweep_amount[i];
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if (i == 0 && apu->sweep_mode[i]) shifted += 1;
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apu->sfreq[i] = apu->freq[i] + (apu->sweep_mode[i] ? -shifted : shifted);
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//DEBUG_OUT("shifted[%d] = %d (%d >> %d)\n",i,shifted,apu->freq[i],apu->sweep_amount[i]);
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}
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void NES_APU_np_FrameSequence(void* chip, int s)
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{
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NES_APU* apu = (NES_APU*)chip;
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int i;
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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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// 240hz clock
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for (i=0; i < 2; ++i)
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{
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bool divider = false;
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if (apu->envelope_write[i])
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{
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apu->envelope_write[i] = false;
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apu->envelope_counter[i] = 15;
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apu->envelope_div[i] = 0;
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}
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else
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{
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++apu->envelope_div[i];
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if (apu->envelope_div[i] > apu->envelope_div_period[i])
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{
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divider = true;
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apu->envelope_div[i] = 0;
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}
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}
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if (divider)
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{
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if (apu->envelope_loop[i] && apu->envelope_counter[i] == 0)
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apu->envelope_counter[i] = 15;
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else if (apu->envelope_counter[i] > 0)
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--apu->envelope_counter[i];
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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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for (i=0; i < 2; ++i)
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{
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if (!apu->envelope_loop[i] && (apu->length_counter[i] > 0))
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--apu->length_counter[i];
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if (apu->sweep_enable[i])
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{
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//DEBUG_OUT("Clock sweep: %d\n", i);
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--apu->sweep_div[i];
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if (apu->sweep_div[i] <= 0)
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{
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sweep_sqr(apu, i); // calculate new sweep target
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//DEBUG_OUT("sweep_div[%d] (0/%d)\n",i,apu->sweep_div_period[i]);
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//DEBUG_OUT("freq[%d]=%d > sfreq[%d]=%d\n",i,apu->freq[i],i,apu->sfreq[i]);
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if (apu->freq[i] >= 8 && apu->sfreq[i] < 0x800 && apu->sweep_amount[i] > 0) // update frequency if appropriate
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{
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apu->freq[i] = apu->sfreq[i] < 0 ? 0 : apu->sfreq[i];
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if (apu->scounter[i] > apu->freq[i]) apu->scounter[i] = apu->freq[i];
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}
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apu->sweep_div[i] = apu->sweep_div_period[i] + 1;
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//DEBUG_OUT("freq[%d]=%d\n",i,apu->freq[i]);
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}
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if (apu->sweep_write[i])
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{
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apu->sweep_div[i] = apu->sweep_div_period[i] + 1;
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apu->sweep_write[i] = false;
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}
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}
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}
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}
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static INT32 calc_sqr(NES_APU* apu, int i, UINT32 clocks)
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{
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static const INT16 sqrtbl[4][16] = {
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{0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
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{0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
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{0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0},
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{1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}
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};
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INT32 ret = 0;
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apu->scounter[i] += clocks;
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while (apu->scounter[i] > apu->freq[i])
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{
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apu->sphase[i] = (apu->sphase[i] + 1) & 15;
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apu->scounter[i] -= (apu->freq[i] + 1);
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}
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//INT32 ret = 0;
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if (apu->length_counter[i] > 0 &&
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apu->freq[i] >= 8 &&
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apu->sfreq[i] < 0x800
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)
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{
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int v = apu->envelope_disable[i] ? apu->volume[i] : apu->envelope_counter[i];
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ret = sqrtbl[apu->duty[i]][apu->sphase[i]] ? v : 0;
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}
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return ret;
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}
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bool NES_APU_np_Read(void* chip, UINT32 adr, UINT32* val)
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{
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NES_APU* apu = (NES_APU*)chip;
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if (0x4000 <= adr && adr < 0x4008)
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{
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*val |= apu->reg[adr&0x7];
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return true;
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}
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else if(adr==0x4015)
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{
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*val |= (apu->length_counter[1]?2:0)|(apu->length_counter[0]?1:0);
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return true;
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}
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else
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return false;
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}
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static void Tick(NES_APU* apu, UINT32 clocks)
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{
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apu->out[0] = calc_sqr(apu, 0, clocks);
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apu->out[1] = calc_sqr(apu, 1, clocks);
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}
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// 生成される波形の振幅は0-8191
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UINT32 NES_APU_np_Render(void* chip, INT32 b[2])
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{
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NES_APU* apu = (NES_APU*)chip;
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INT32 m[2];
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COUNTER_iup(apu->tick_count);
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Tick(apu, (COUNTER_value(apu->tick_count) - apu->tick_last) & 0xFF);
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apu->tick_last = COUNTER_value(apu->tick_count);
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apu->out[0] = (apu->mask & 1) ? 0 : apu->out[0];
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apu->out[1] = (apu->mask & 2) ? 0 : apu->out[1];
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if(apu->option[OPT_NONLINEAR_MIXER])
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{
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INT32 voltage;
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INT32 ref;
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voltage = apu->square_table[apu->out[0] + apu->out[1]];
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m[0] = apu->out[0] << 6;
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m[1] = apu->out[1] << 6;
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ref = m[0] + m[1];
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if (ref > 0)
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{
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m[0] = (m[0] * voltage) / ref;
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m[1] = (m[1] * voltage) / ref;
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}
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else
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{
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m[0] = voltage;
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m[1] = voltage;
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}
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}
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else
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{
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m[0] = apu->out[0] << 6;
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m[1] = apu->out[1] << 6;
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}
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// Shifting is (x-2) to match the volume of MAME's NES APU sound core
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b[0] = m[0] * apu->sm[0][0];
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b[0] += m[1] * apu->sm[0][1];
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b[0] >>= 7-2; // was 7, but is now 8 for bipolar square
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b[1] = m[0] * apu->sm[1][0];
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b[1] += m[1] * apu->sm[1][1];
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b[1] >>= 7-2; // see above
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return 2;
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}
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void* NES_APU_np_Create(int clock, int rate)
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{
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NES_APU* apu;
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int i, c, t;
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apu = (NES_APU*)malloc(sizeof(NES_APU));
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if (apu == NULL)
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return NULL;
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memset(apu, 0x00, sizeof(NES_APU));
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//NES_APU_np_SetClock(apu, DEFAULT_CLOCK);
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//NES_APU_np_SetRate(apu, DEFAULT_RATE);
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NES_APU_np_SetClock(apu, clock);
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NES_APU_np_SetRate(apu, rate);
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apu->option[OPT_UNMUTE_ON_RESET] = true;
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apu->option[OPT_PHASE_REFRESH] = true;
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apu->option[OPT_NONLINEAR_MIXER] = true;
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apu->option[OPT_DUTY_SWAP] = false;
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apu->square_table[0] = 0;
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for(i=1;i<32;i++)
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apu->square_table[i]=(INT32)((8192.0*95.88)/(8128.0/i+100));
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for(c=0;c<2;++c)
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for(t=0;t<2;++t)
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apu->sm[c][t] = 128;
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return apu;
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}
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void NES_APU_np_Destroy(void* chip)
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{
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free(chip);
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}
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void NES_APU_np_Reset(void* chip)
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{
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NES_APU* apu = (NES_APU*)chip;
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int i;
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apu->gclock = 0;
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apu->mask = 0;
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apu->scounter[0] = 0;
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apu->scounter[1] = 0;
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apu->sphase[0] = 0;
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apu->sphase[0] = 0;
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apu->sweep_div[0] = 1;
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apu->sweep_div[1] = 1;
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apu->envelope_div[0] = 0;
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apu->envelope_div[1] = 0;
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apu->length_counter[0] = 0;
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apu->length_counter[1] = 0;
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apu->envelope_counter[0] = 0;
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apu->envelope_counter[1] = 0;
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for (i = 0x4000; i < 0x4008; i++)
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NES_APU_np_Write(apu, i, 0);
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NES_APU_np_Write(apu, 0x4015, 0);
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if (apu->option[OPT_UNMUTE_ON_RESET])
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NES_APU_np_Write(apu, 0x4015, 0x0f);
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for (i = 0; i < 2; i++)
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apu->out[i] = 0;
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NES_APU_np_SetRate(apu, apu->rate);
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}
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void NES_APU_np_SetOption(void* chip, int id, int val)
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{
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NES_APU* apu = (NES_APU*)chip;
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if(id<OPT_END) apu->option[id] = val;
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}
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void NES_APU_np_SetClock(void* chip, double c)
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{
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NES_APU* apu = (NES_APU*)chip;
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apu->clock = c;
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}
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void NES_APU_np_SetRate(void* chip, double r)
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{
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NES_APU* apu = (NES_APU*)chip;
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apu->rate = r ? r : DEFAULT_RATE;
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COUNTER_init(apu->tick_count, apu->clock, apu->rate);
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apu->tick_last = 0;
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}
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void NES_APU_np_SetMask(void* chip, int m)
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{
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NES_APU* apu = (NES_APU*)chip;
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apu->mask = m;
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}
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void NES_APU_np_SetStereoMix(void* chip, int trk, INT16 mixl, INT16 mixr)
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{
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NES_APU* apu = (NES_APU*)chip;
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if (trk < 0) return;
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if (trk > 1) return;
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apu->sm[0][trk] = mixl;
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apu->sm[1][trk] = mixr;
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}
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bool NES_APU_np_Write(void* chip, UINT32 adr, UINT32 val)
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{
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NES_APU* apu = (NES_APU*)chip;
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int ch;
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static const UINT8 length_table[32] = {
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0x0A, 0xFE,
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0x14, 0x02,
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0x28, 0x04,
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0x50, 0x06,
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0xA0, 0x08,
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0x3C, 0x0A,
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0x0E, 0x0C,
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0x1A, 0x0E,
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0x0C, 0x10,
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0x18, 0x12,
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0x30, 0x14,
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0x60, 0x16,
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0xC0, 0x18,
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0x48, 0x1A,
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0x10, 0x1C,
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0x20, 0x1E
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};
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if (0x4000 <= adr && adr < 0x4008)
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{
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//DEBUG_OUT("$%04X = %02X\n",adr,val);
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adr &= 0xf;
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ch = adr >> 2;
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switch (adr)
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{
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case 0x0:
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case 0x4:
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apu->volume[ch] = val & 15;
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apu->envelope_disable[ch] = (val >> 4) & 1;
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apu->envelope_loop[ch] = (val >> 5) & 1;
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apu->envelope_div_period[ch] = (val & 15);
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apu->duty[ch] = (val >> 6) & 3;
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if (apu->option[OPT_DUTY_SWAP])
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{
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if (apu->duty[ch] == 1) apu->duty[ch] = 2;
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else if (apu->duty[ch] == 2) apu->duty[ch] = 1;
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}
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break;
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case 0x1:
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case 0x5:
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apu->sweep_enable[ch] = (val >> 7) & 1;
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apu->sweep_div_period[ch] = (((val >> 4) & 7));
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apu->sweep_mode[ch] = (val >> 3) & 1;
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apu->sweep_amount[ch] = val & 7;
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apu->sweep_write[ch] = true;
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sweep_sqr(apu, ch);
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break;
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case 0x2:
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case 0x6:
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apu->freq[ch] = val | (apu->freq[ch] & 0x700) ;
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sweep_sqr(apu, ch);
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if (apu->scounter[ch] > apu->freq[ch]) apu->scounter[ch] = apu->freq[ch];
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break;
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case 0x3:
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case 0x7:
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apu->freq[ch] = (apu->freq[ch] & 0xFF) | ((val & 0x7) << 8) ;
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if (apu->option[OPT_PHASE_REFRESH])
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apu->sphase[ch] = 0;
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apu->envelope_write[ch] = true;
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if (apu->enable[ch])
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{
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apu->length_counter[ch] = length_table[(val >> 3) & 0x1f];
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}
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sweep_sqr(apu, ch);
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if (apu->scounter[ch] > apu->freq[ch]) apu->scounter[ch] = apu->freq[ch];
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break;
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default:
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return false;
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}
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|
apu->reg[adr] = val;
|
|
return true;
|
|
}
|
|
else if (adr == 0x4015)
|
|
{
|
|
apu->enable[0] = (val & 1) ? true : false;
|
|
apu->enable[1] = (val & 2) ? true : false;
|
|
|
|
if (!apu->enable[0])
|
|
apu->length_counter[0] = 0;
|
|
if (!apu->enable[1])
|
|
apu->length_counter[1] = 0;
|
|
|
|
apu->reg[adr-0x4000] = val;
|
|
return true;
|
|
}
|
|
|
|
// 4017 is handled in np_nes_dmc.c
|
|
//else if (adr == 0x4017)
|
|
//{
|
|
//}
|
|
|
|
return false;
|
|
}
|