cog/Frameworks/GME/vgmplay/chips/np_nes_dmc.c

872 lines
19 KiB
C

// Ported from NSFPlay to VGMPlay (including C++ -> C conversion)
// by Valley Bell on 25 September 2013
// Updated to NSFPlay 2.3 on 26 September 2013
// (Note: Encoding is UTF-8)
#include <stdlib.h> // for rand()
#include <memory.h> // for memset()
#include <stddef.h> // for NULL
#include "mamedef.h"
#include "../stdbool.h"
#include "np_nes_apu.h" // for NES_APU_np_FrameSequence
#include "np_nes_dmc.h"
// Master Clock: 21477272 (NTSC)
// APU Clock = Master Clock / 12
#define DEFAULT_CLOCK 1789772.0
#define DEFAULT_CLK_PAL 1662607
#define DEFAULT_RATE 44100
/** Bottom Half of APU **/
enum
{
OPT_UNMUTE_ON_RESET=0,
OPT_NONLINEAR_MIXER,
OPT_ENABLE_4011,
OPT_ENABLE_PNOISE,
OPT_DPCM_ANTI_CLICK,
OPT_RANDOMIZE_NOISE,
OPT_TRI_MUTE,
OPT_TRI_NULL,
OPT_END
};
// Note: For increased speed, I'll inline all of NSFPlay's Counter member functions.
#define COUNTER_SHIFT 24
typedef struct _Counter Counter;
struct _Counter
{
double ratio;
UINT32 val, step;
};
#define COUNTER_setcycle(cntr, s) (cntr).step = (UINT32)((cntr).ratio / (s + 1))
#define COUNTER_iup(cntr) (cntr).val += (cntr).step
#define COUNTER_value(cntr) ((cntr).val >> COUNTER_SHIFT)
#define COUNTER_init(cntr, clk, rate) \
{ \
(cntr).ratio = (1 << COUNTER_SHIFT) * (1.0 * clk / rate); \
(cntr).step = (UINT32)((cntr).ratio + 0.5); \
(cntr).val = 0; \
}
typedef struct _NES_DMC NES_DMC;
struct _NES_DMC
{
//const int GETA_BITS;
//static const UINT32 freq_table[2][16];
//static const UINT32 wavlen_table[2][16];
UINT32 tnd_table[2][16][16][128];
int option[OPT_END];
int mask;
INT32 sm[2][3];
UINT8 reg[0x10];
UINT32 len_reg;
UINT32 adr_reg;
//IDevice *memory;
const UINT8* memory;
UINT32 out[3];
UINT32 daddress;
UINT32 length;
UINT32 data;
INT16 damp;
int dac_lsb;
bool dmc_pop;
INT32 dmc_pop_offset;
INT32 dmc_pop_follow;
UINT32 clock;
UINT32 rate;
int pal;
int mode;
bool irq;
bool active;
UINT32 counter[3]; // frequency dividers
int tphase; // triangle phase
UINT32 nfreq; // noise frequency
UINT32 dfreq; // DPCM frequency
UINT32 tri_freq;
int linear_counter;
int linear_counter_reload;
bool linear_counter_halt;
bool linear_counter_control;
int noise_volume;
UINT32 noise, noise_tap;
// noise envelope
bool envelope_loop;
bool envelope_disable;
bool envelope_write;
int envelope_div_period;
int envelope_div;
int envelope_counter;
bool enable[3];
int length_counter[2]; // 0=tri, 1=noise
// frame sequencer
void* apu; // apu is clocked by DMC's frame sequencer
int frame_sequence_count; // current cycle count
int frame_sequence_length; // CPU cycles per FrameSequence
int frame_sequence_step; // current step of frame sequence
int frame_sequence_steps; // 4/5 steps per frame
bool frame_irq;
bool frame_irq_enable;
Counter tick_count;
UINT32 tick_last;
};
INLINE UINT32 calc_tri(NES_DMC* dmc, UINT32 clocks);
INLINE UINT32 calc_dmc(NES_DMC* dmc, UINT32 clocks);
INLINE UINT32 calc_noise(NES_DMC* dmc, UINT32 clocks);
static void FrameSequence(NES_DMC* dmc, int s);
static void TickFrameSequence(NES_DMC* dmc, UINT32 clocks);
static void Tick(NES_DMC* dmc, UINT32 clocks);
#define GETA_BITS 20
static const UINT32 wavlen_table[2][16] = {
{ // NTSC
4, 8, 16, 32, 64, 96, 128, 160, 202, 254, 380, 508, 762, 1016, 2034, 4068
},
{ // PAL
4, 8, 14, 30, 60, 88, 118, 148, 188, 236, 354, 472, 708, 944, 1890, 3778
}};
static const UINT32 freq_table[2][16] = {
{ // NTSC
428, 380, 340, 320, 286, 254, 226, 214, 190, 160, 142, 128, 106, 84, 72, 54
},
{ // PAL
398, 354, 316, 298, 276, 236, 210, 198, 176, 148, 132, 118, 98, 78, 66, 50
}};
void* NES_DMC_np_Create(int clock, int rate)
{
NES_DMC* dmc;
int c, t;
dmc = (NES_DMC*)malloc(sizeof(NES_DMC));
if (dmc == NULL)
return NULL;
memset(dmc, 0x00, sizeof(NES_DMC));
//NES_DMC_np_SetClock(dmc, DEFAULT_CLOCK);
//NES_DMC_np_SetRate(dmc, DEFAULT_RATE);
//NES_DMC_np_SetPal(dmc, false);
NES_DMC_np_SetClock(dmc, clock); // does SetPal, too
NES_DMC_np_SetRate(dmc, rate);
dmc->option[OPT_ENABLE_4011] = 1;
dmc->option[OPT_ENABLE_PNOISE] = 1;
dmc->option[OPT_UNMUTE_ON_RESET] = 1;
dmc->option[OPT_DPCM_ANTI_CLICK] = 0;
dmc->option[OPT_NONLINEAR_MIXER] = 1;
dmc->option[OPT_RANDOMIZE_NOISE] = 1;
dmc->option[OPT_TRI_MUTE] = 1;
dmc->tnd_table[0][0][0][0] = 0;
dmc->tnd_table[1][0][0][0] = 0;
dmc->apu = NULL;
dmc->frame_sequence_count = 0;
dmc->frame_sequence_length = 7458;
dmc->frame_sequence_steps = 4;
for(c=0;c<2;++c)
for(t=0;t<3;++t)
dmc->sm[c][t] = 128;
return dmc;
}
void NES_DMC_np_Destroy(void* chip)
{
free(chip);
}
int NES_DMC_np_GetDamp(void* chip)
{
NES_DMC* dmc = (NES_DMC*)chip;
return (dmc->damp<<1)|dmc->dac_lsb;
}
void NES_DMC_np_SetMask(void* chip, int m)
{
NES_DMC* dmc = (NES_DMC*)chip;
dmc->mask = m;
}
void NES_DMC_np_SetStereoMix(void* chip, int trk, INT16 mixl, INT16 mixr)
{
NES_DMC* dmc = (NES_DMC*)chip;
if (trk < 0) return;
if (trk > 2) return;
dmc->sm[0][trk] = mixl;
dmc->sm[1][trk] = mixr;
}
static void FrameSequence(NES_DMC* dmc, int s)
{
//DEBUG_OUT("FrameSequence: %d\n",s);
if (s > 3) return; // no operation in step 4
if (dmc->apu != NULL)
{
NES_APU_np_FrameSequence(dmc->apu, s);
}
if (s == 0 && (dmc->frame_sequence_steps == 4))
{
dmc->frame_irq = true;
}
// 240hz clock
{
bool divider = false;
// triangle linear counter
if (dmc->linear_counter_halt)
{
dmc->linear_counter = dmc->linear_counter_reload;
}
else
{
if (dmc->linear_counter > 0) --dmc->linear_counter;
}
if (!dmc->linear_counter_control)
{
dmc->linear_counter_halt = false;
}
// noise envelope
//bool divider = false;
if (dmc->envelope_write)
{
dmc->envelope_write = false;
dmc->envelope_counter = 15;
dmc->envelope_div = 0;
}
else
{
++dmc->envelope_div;
if (dmc->envelope_div > dmc->envelope_div_period)
{
divider = true;
dmc->envelope_div = 0;
}
}
if (divider)
{
if (dmc->envelope_loop && dmc->envelope_counter == 0)
dmc->envelope_counter = 15;
else if (dmc->envelope_counter > 0)
--dmc->envelope_counter; // TODO: Make this work.
}
}
// 120hz clock
if ((s&1) == 0)
{
// triangle length counter
if (!dmc->linear_counter_control && (dmc->length_counter[0] > 0))
--dmc->length_counter[0];
// noise length counter
if (!dmc->envelope_loop && (dmc->length_counter[1] > 0))
--dmc->length_counter[1];
}
}
// 三角波チャンネルの計算 戻り値は0-15
UINT32 calc_tri(NES_DMC* dmc, UINT32 clocks)
{
static UINT32 tritbl[32] =
{
0, 1, 2, 3, 4, 5, 6, 7,
8, 9,10,11,12,13,14,15,
15,14,13,12,11,10, 9, 8,
7, 6, 5, 4, 3, 2, 1, 0
};
if (dmc->linear_counter > 0 && dmc->length_counter[0] > 0
&& (!dmc->option[OPT_TRI_MUTE] || dmc->tri_freq > 0))
{
dmc->counter[0] += clocks;
while (dmc->counter[0] > dmc->tri_freq)
{
dmc->tphase = (dmc->tphase + 1) & 31;
dmc->counter[0] -= (dmc->tri_freq + 1);
}
}
// Note: else-block added by VB
else if (dmc->option[OPT_TRI_NULL])
{
if (dmc->tphase && dmc->tphase < 31)
{
// Finish the Triangle wave to prevent clicks.
dmc->counter[0] += clocks;
while(dmc->counter[0] > dmc->tri_freq && dmc->tphase)
{
dmc->tphase = (dmc->tphase + 1) & 31;
dmc->counter[0] -= (dmc->tri_freq + 1);
}
}
}
//UINT32 ret = tritbl[tphase];
//return ret;
return tritbl[dmc->tphase];
}
// ノイズチャンネルの計算 戻り値は0-127
// 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
// 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
// 変換を行っている。
UINT32 calc_noise(NES_DMC* dmc, UINT32 clocks)
{
UINT32 env, last, count, accum, clocks_accum;
env = dmc->envelope_disable ? dmc->noise_volume : dmc->envelope_counter;
if (dmc->length_counter[1] < 1) env = 0;
last = (dmc->noise & 0x4000) ? env : 0;
if (clocks < 1) return last;
// simple anti-aliasing (noise requires it, even when oversampling is off)
count = 0;
accum = 0;
dmc->counter[1] += clocks;
// assert(dmc->nfreq > 0); // prevent infinite loop
if (dmc->nfreq <= 0) // prevent infinite loop -VB
return last;
while (dmc->counter[1] >= dmc->nfreq)
{
// tick the noise generator
UINT32 feedback = (dmc->noise&1) ^ ((dmc->noise&dmc->noise_tap)?1:0);
dmc->noise = (dmc->noise>>1) | (feedback<<14);
++count;
accum += last;
last = (dmc->noise & 0x4000) ? env : 0;
dmc->counter[1] -= dmc->nfreq;
}
if (count < 1) // no change over interval, don't anti-alias
{
return last;
}
clocks_accum = clocks - dmc->counter[1];
// count = number of samples in accum
// counter[1] = number of clocks since last sample
accum = (accum * clocks_accum) + (last * dmc->counter[1] * count);
// note accum as an average is already premultiplied by count
return accum / (clocks * count);
}
// DMCチャンネルの計算 戻り値は0-127
UINT32 calc_dmc(NES_DMC* dmc, UINT32 clocks)
{
dmc->counter[2] += clocks;
// assert(dmc->dfreq > 0); // prevent infinite loop
if (dmc->dfreq <= 0) // prevent infinite loop -VB
return (dmc->damp<<1) + dmc->dac_lsb;
while (dmc->counter[2] >= dmc->dfreq)
{
if ( dmc->data != 0x100 ) // data = 0x100 は EMPTY を意味する。
{
if ((dmc->data & 1) && (dmc->damp < 63))
dmc->damp++;
else if (!(dmc->data & 1) && (0 < dmc->damp))
dmc->damp--;
dmc->data >>=1;
}
if ( dmc->data == 0x100 && dmc->active )
{
//dmc->memory->Read(dmc->daddress, dmc->data);
dmc->data = dmc->memory[dmc->daddress];
dmc->data |= (dmc->data&0xFF)|0x10000; // 8bitシフトで 0x100 になる
if ( dmc->length > 0 )
{
dmc->daddress = ((dmc->daddress+1)&0xFFFF)|0x8000 ;
dmc->length --;
}
}
if ( dmc->length == 0 ) // 最後のフェッチが終了したら(再生完了より前に)即座に終端処理
{
if (dmc->mode & 1)
{
dmc->daddress = ((dmc->adr_reg<<6)|0xC000);
dmc->length = (dmc->len_reg<<4)+1;
}
else
{
dmc->irq = (dmc->mode==2&&dmc->active)?1:0; // 直前がactiveだったときはIRQ発行
dmc->active = false;
}
}
dmc->counter[2] -= dmc->dfreq;
}
return (dmc->damp<<1) + dmc->dac_lsb;
}
static void TickFrameSequence(NES_DMC* dmc, UINT32 clocks)
{
dmc->frame_sequence_count += clocks;
while (dmc->frame_sequence_count > dmc->frame_sequence_length)
{
FrameSequence(dmc, dmc->frame_sequence_step);
dmc->frame_sequence_count -= dmc->frame_sequence_length;
++dmc->frame_sequence_step;
if(dmc->frame_sequence_step >= dmc->frame_sequence_steps)
dmc->frame_sequence_step = 0;
}
}
static void Tick(NES_DMC* dmc, UINT32 clocks)
{
dmc->out[0] = calc_tri(dmc, clocks);
dmc->out[1] = calc_noise(dmc, clocks);
dmc->out[2] = calc_dmc(dmc, clocks);
}
UINT32 NES_DMC_np_Render(void* chip, INT32 b[2])
{
NES_DMC* dmc = (NES_DMC*)chip;
UINT32 clocks;
INT32 m[3];
COUNTER_iup(dmc->tick_count); // increase counter (overflows after 255)
clocks = (COUNTER_value(dmc->tick_count) - dmc->tick_last) & 0xFF;
TickFrameSequence(dmc, clocks);
Tick(dmc, clocks);
dmc->tick_last = COUNTER_value(dmc->tick_count);
dmc->out[0] = (dmc->mask & 1) ? 0 : dmc->out[0];
dmc->out[1] = (dmc->mask & 2) ? 0 : dmc->out[1];
dmc->out[2] = (dmc->mask & 4) ? 0 : dmc->out[2];
m[0] = dmc->tnd_table[0][dmc->out[0]][0][0];
m[1] = dmc->tnd_table[0][0][dmc->out[1]][0];
m[2] = dmc->tnd_table[0][0][0][dmc->out[2]];
if (dmc->option[OPT_NONLINEAR_MIXER])
{
INT32 ref = m[0] + m[1] + m[2];
INT32 voltage = dmc->tnd_table[1][dmc->out[0]][dmc->out[1]][dmc->out[2]];
int i;
if (ref)
{
for (i=0; i < 3; ++i)
m[i] = (m[i] * voltage) / ref;
}
else
{
for (i=0; i < 3; ++i)
m[i] = voltage;
}
}
// anti-click nullifies any 4011 write but preserves nonlinearity
if (dmc->option[OPT_DPCM_ANTI_CLICK])
{
if (dmc->dmc_pop) // $4011 will cause pop this frame
{
// adjust offset to counteract pop
dmc->dmc_pop_offset += dmc->dmc_pop_follow - m[2];
dmc->dmc_pop = false;
// prevent overflow, keep headspace at edges
//const INT32 OFFSET_MAX = (1 << 30) - (4 << 16);
#define OFFSET_MAX ((1 << 30) - (4 << 16))
if (dmc->dmc_pop_offset > OFFSET_MAX) dmc->dmc_pop_offset = OFFSET_MAX;
if (dmc->dmc_pop_offset < -OFFSET_MAX) dmc->dmc_pop_offset = -OFFSET_MAX;
}
dmc->dmc_pop_follow = m[2]; // remember previous position
m[2] += dmc->dmc_pop_offset; // apply offset
// TODO implement this in a better way
// roll off offset (not ideal, but prevents overflow)
if (dmc->dmc_pop_offset > 0) --dmc->dmc_pop_offset;
else if (dmc->dmc_pop_offset < 0) ++dmc->dmc_pop_offset;
}
b[0] = m[0] * dmc->sm[0][0];
b[0] += m[1] * dmc->sm[0][1];
b[0] +=-m[2] * dmc->sm[0][2];
b[0] >>= 7-2;
b[1] = m[0] * dmc->sm[1][0];
b[1] += m[1] * dmc->sm[1][1];
b[1] +=-m[2] * dmc->sm[1][2];
b[1] >>= 7-2;
return 2;
}
void NES_DMC_np_SetClock(void* chip, double c)
{
NES_DMC* dmc = (NES_DMC*)chip;
dmc->clock = (UINT32)(c);
if (abs(dmc->clock - DEFAULT_CLK_PAL) <= 1000) // check for approximately DEFAULT_CLK_PAL
NES_DMC_np_SetPal(dmc, true);
else
NES_DMC_np_SetPal(dmc, false);
}
void NES_DMC_np_SetRate(void* chip, double r)
{
NES_DMC* dmc = (NES_DMC*)chip;
dmc->rate = (UINT32)(r?r:DEFAULT_RATE);
COUNTER_init(dmc->tick_count, dmc->clock, dmc->rate);
dmc->tick_last = 0;
}
void NES_DMC_np_SetPal(void* chip, bool is_pal)
{
NES_DMC* dmc = (NES_DMC*)chip;
dmc->pal = (is_pal ? 1 : 0);
// set CPU cycles in frame_sequence
dmc->frame_sequence_length = is_pal ? 8314 : 7458;
}
void NES_DMC_np_SetAPU(void* chip, void* apu_)
{
NES_DMC* dmc = (NES_DMC*)chip;
dmc->apu = apu_;
}
// Initializing TRI, NOISE, DPCM mixing table
static void InitializeTNDTable(NES_DMC* dmc, double wt, double wn, double wd)
{
// volume adjusted by 0.75 based on empirical measurements
const double MASTER = 8192.0 * 0.75;
// truthfully, the nonlinear curve does not appear to match well
// with my tests, triangle in particular seems too quiet relatively.
// do more testing of the APU/DMC DAC later
int t, n, d;
{ // Linear Mixer
for(t=0; t<16 ; t++) {
for(n=0; n<16; n++) {
for(d=0; d<128; d++) {
dmc->tnd_table[0][t][n][d] = (UINT32)(MASTER*(3.0*t+2.0*n+d)/208.0);
}
}
}
}
{ // Non-Linear Mixer
dmc->tnd_table[1][0][0][0] = 0;
for(t=0; t<16 ; t++) {
for(n=0; n<16; n++) {
for(d=0; d<128; d++) {
if(t!=0||n!=0||d!=0)
dmc->tnd_table[1][t][n][d] = (UINT32)((MASTER*159.79)/(100.0+1.0/((double)t/wt+(double)n/wn+(double)d/wd)));
}
}
}
}
}
void NES_DMC_np_Reset(void* chip)
{
NES_DMC* dmc = (NES_DMC*)chip;
int i;
dmc->mask = 0;
InitializeTNDTable(dmc,8227,12241,22638);
dmc->counter[0] = 0;
dmc->counter[1] = 0;
dmc->counter[2] = 0;
dmc->tphase = 0;
dmc->nfreq = wavlen_table[0][0];
dmc->dfreq = freq_table[0][0];
dmc->envelope_div = 0;
dmc->length_counter[0] = 0;
dmc->length_counter[1] = 0;
dmc->linear_counter = 0;
dmc->envelope_counter = 0;
dmc->frame_irq = false;
dmc->frame_irq_enable = false;
dmc->frame_sequence_count = 0;
dmc->frame_sequence_steps = 4;
dmc->frame_sequence_step = 0;
for (i = 0; i < 0x10; i++)
NES_DMC_np_Write(dmc, 0x4008 + i, 0);
dmc->irq = false;
NES_DMC_np_Write(dmc, 0x4015, 0x00);
if (dmc->option[OPT_UNMUTE_ON_RESET])
NES_DMC_np_Write(dmc, 0x4015, 0x0f);
dmc->out[0] = dmc->out[1] = dmc->out[2] = 0;
dmc->tri_freq = 0;
dmc->damp = 0;
dmc->dmc_pop = false;
dmc->dmc_pop_offset = 0;
dmc->dmc_pop_follow = 0;
dmc->dac_lsb = 0;
dmc->data = 0x100;
dmc->adr_reg = 0;
dmc->active = false;
dmc->length = 0;
dmc->len_reg = 0;
dmc->daddress = 0;
dmc->noise = 1;
dmc->noise_tap = (1<<1);
if (dmc->option[OPT_RANDOMIZE_NOISE])
{
dmc->noise |= rand();
}
NES_DMC_np_SetRate(dmc, dmc->rate);
}
void NES_DMC_np_SetMemory(void* chip, const UINT8* r)
{
NES_DMC* dmc = (NES_DMC*)chip;
dmc->memory = r;
}
void NES_DMC_np_SetOption(void* chip, int id, int val)
{
NES_DMC* dmc = (NES_DMC*)chip;
if(id<OPT_END)
{
dmc->option[id] = val;
if(id==OPT_NONLINEAR_MIXER)
InitializeTNDTable(dmc, 8227,12241,22638);
}
}
bool NES_DMC_np_Write(void* chip, UINT32 adr, UINT32 val)
{
static const UINT8 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
};
NES_DMC* dmc = (NES_DMC*)chip;
if (adr == 0x4015)
{
dmc->enable[0] = (val & 4) ? true : false;
dmc->enable[1] = (val & 8) ? true : false;
if (!dmc->enable[0])
{
dmc->length_counter[0] = 0;
}
if (!dmc->enable[1])
{
dmc->length_counter[1] = 0;
}
if ((val & 16)&&!dmc->active)
{
dmc->enable[2] = dmc->active = true;
dmc->daddress = (0xC000 | (dmc->adr_reg << 6));
dmc->length = (dmc->len_reg << 4) + 1;
dmc->irq = 0;
}
else if (!(val & 16))
{
dmc->enable[2] = dmc->active = false;
}
dmc->reg[adr-0x4008] = val;
return true;
}
if (adr == 0x4017)
{
//DEBUG_OUT("4017 = %02X\n", val);
dmc->frame_irq_enable = ((val & 0x40) == 0x40);
dmc->frame_irq = (dmc->frame_irq_enable ? dmc->frame_irq : 0);
dmc->frame_sequence_count = 0;
if (val & 0x80)
{
dmc->frame_sequence_steps = 5;
dmc->frame_sequence_step = 0;
FrameSequence(dmc, dmc->frame_sequence_step);
++dmc->frame_sequence_step;
}
else
{
dmc->frame_sequence_steps = 4;
dmc->frame_sequence_step = 1;
}
}
if (adr<0x4008||0x4013<adr)
return false;
dmc->reg[adr-0x4008] = val&0xff;
//DEBUG_OUT("$%04X %02X\n", adr, val);
switch (adr)
{
// tri
case 0x4008:
dmc->linear_counter_control = (val >> 7) & 1;
dmc->linear_counter_reload = val & 0x7F;
break;
case 0x4009:
break;
case 0x400a:
dmc->tri_freq = val | (dmc->tri_freq & 0x700) ;
if (dmc->counter[0] > dmc->tri_freq) dmc->counter[0] = dmc->tri_freq;
break;
case 0x400b:
dmc->tri_freq = (dmc->tri_freq & 0xff) | ((val & 0x7) << 8) ;
if (dmc->counter[0] > dmc->tri_freq) dmc->counter[0] = dmc->tri_freq;
dmc->linear_counter_halt = true;
if (dmc->enable[0])
{
dmc->length_counter[0] = length_table[(val >> 3) & 0x1f];
}
break;
// noise
case 0x400c:
dmc->noise_volume = val & 15;
dmc->envelope_div_period = val & 15;
dmc->envelope_disable = (val >> 4) & 1;
dmc->envelope_loop = (val >> 5) & 1;
break;
case 0x400d:
break;
case 0x400e:
if (dmc->option[OPT_ENABLE_PNOISE])
dmc->noise_tap = (val & 0x80) ? (1<<6) : (1<<1);
else
dmc->noise_tap = (1<<1);
dmc->nfreq = wavlen_table[dmc->pal][val&15];
if (dmc->counter[1] > dmc->nfreq) dmc->counter[1] = dmc->nfreq;
break;
case 0x400f:
if (dmc->enable[1])
{
dmc->length_counter[1] = length_table[(val >> 3) & 0x1f];
}
dmc->envelope_write = true;
break;
// dmc
case 0x4010:
dmc->mode = (val >> 6) & 3;
dmc->dfreq = freq_table[dmc->pal][val&15];
if (dmc->counter[2] > dmc->dfreq) dmc->counter[2] = dmc->dfreq;
break;
case 0x4011:
if (dmc->option[OPT_ENABLE_4011])
{
dmc->damp = (val >> 1) & 0x3f;
dmc->dac_lsb = val & 1;
dmc->dmc_pop = true;
}
break;
case 0x4012:
dmc->adr_reg = val&0xff;
// ここでdaddressは更新されない
break;
case 0x4013:
dmc->len_reg = val&0xff;
// ここでlengthは更新されない
break;
default:
return false;
}
return true;
}
bool NES_DMC_np_Read(void* chip, UINT32 adr, UINT32* val)
{
NES_DMC* dmc = (NES_DMC*)chip;
if (adr == 0x4015)
{
*val |= (dmc->irq?128:0)
| (dmc->frame_irq ? 0x40 : 0)
| (dmc->active?16:0)
| (dmc->length_counter[1]?8:0)
| (dmc->length_counter[0]?4:0)
;
dmc->frame_irq = false;
return true;
}
else if (0x4008<=adr&&adr<=0x4014)
{
*val |= dmc->reg[adr-0x4008];
return true;
}
else
return false;
}