NES system! almost

This commit is contained in:
tildearrow 2021-12-04 01:19:54 -05:00
parent 6446e876ae
commit 3286c3c0c5
9 changed files with 688 additions and 10 deletions

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@ -47,6 +47,7 @@ src/engine/platform/genesisext.cpp
src/engine/platform/sms.cpp src/engine/platform/sms.cpp
src/engine/platform/gb.cpp src/engine/platform/gb.cpp
src/engine/platform/pce.cpp src/engine/platform/pce.cpp
src/engine/platform/nes.cpp
src/engine/platform/dummy.cpp) src/engine/platform/dummy.cpp)
#imgui/imgui.cpp #imgui/imgui.cpp

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@ -6,10 +6,10 @@ this is a work-in-progress chip music player (currently) for the .dmf format.
## features ## features
- supports Sega Genesis, Master System, Game Boy and PC Engine (for now, with more systems coming soon) - supports Sega Genesis, Master System, Game Boy, PC Engine and NES (for now, with more systems coming soon)
- clean-room design (zero reverse-engineered code and zero decompilation; using official DMF specs, guesswork and ABX tests only) - clean-room design (zero reverse-engineered code and zero decompilation; using official DMF specs, guesswork and ABX tests only)
- bug/quirk implementation for increased playback accuracy - bug/quirk implementation for increased playback accuracy
- accurate emulation cores (Nuked, MAME, SameBoy and Mednafen PCE) - accurate emulation cores (Nuked, MAME, SameBoy, Mednafen PCE and puNES)
- open-source. GPLv2. - open-source. GPLv2.
## dependencies ## dependencies

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@ -10,6 +10,7 @@
#include "platform/sms.h" #include "platform/sms.h"
#include "platform/gb.h" #include "platform/gb.h"
#include "platform/pce.h" #include "platform/pce.h"
#include "platform/nes.h"
#include "platform/dummy.h" #include "platform/dummy.h"
#include <math.h> #include <math.h>
#include <zlib.h> #include <zlib.h>
@ -756,6 +757,9 @@ bool DivEngine::init() {
case DIV_SYSTEM_PCE: case DIV_SYSTEM_PCE:
dispatch=new DivPlatformPCE; dispatch=new DivPlatformPCE;
break; break;
case DIV_SYSTEM_NES:
dispatch=new DivPlatformNES;
break;
default: default:
logW("this system is not supported yet! using dummy platform.\n"); logW("this system is not supported yet! using dummy platform.\n");
dispatch=new DivPlatformDummy; dispatch=new DivPlatformDummy;

305
src/engine/platform/nes.cpp Normal file
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@ -0,0 +1,305 @@
#include "nes.h"
#include "sound/nes/cpu_inline.h"
#include "../engine.h"
#include <math.h>
#define FREQ_BASE 3424.0f
void DivPlatformNES::acquire(int& l, int& r) {
if (dacSample!=-1) {
dacPeriod+=dacRate;
if (dacPeriod>=rate) {
DivSample* s=parent->song.sample[dacSample];
if (s->depth==8) {
apu_wr_reg(0x4011,((unsigned char)s->rendData[dacPos++]+0x80)>>1);
} else {
apu_wr_reg(0x4011,((unsigned short)s->rendData[dacPos++]+0x8000)>>9);
}
if (dacPos>=s->rendLength) {
dacSample=-1;
}
dacPeriod-=rate;
}
}
apu_tick(NULL);
apu.odd_cycle=!apu.odd_cycle;
if (apu.clocked) {
apu.clocked=false;
l=(pulse_output()+tnd_output())*30;
r=l;
//printf("output value: %d\n",l);
}
}
static int dacRates[6]={
4000, 8000, 11025, 16000, 22050, 32000
};
static unsigned char noiseTable[256]={
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 7, 6,
15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4,
15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4,
3, 2, 1, 0, 12, 11, 10, 9, 8, 7, 6, 5, 4,
15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4,
3, 2, 1, 0, 12, 11, 10, 9, 8, 7, 6, 5, 4,
15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4,
3, 2, 1, 0, 12, 11, 10, 9, 8, 7, 6, 5, 4,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15
};
void DivPlatformNES::tick() {
for (int i=0; i<4; i++) {
chan[i].std.next();
if (chan[i].std.hadVol) {
chan[i].outVol=(chan[i].vol*chan[i].std.vol)/15;
if (i==2) { // triangle
apu_wr_reg(0x4000+i*4,(chan[i].outVol==0)?0:255);
} else {
apu_wr_reg(0x4000+i*4,0x30|chan[i].outVol|((chan[i].duty&3)<<6));
}
}
if (chan[i].std.hadArp) {
if (i==3) { // noise
if (chan[i].std.arpMode) {
chan[i].baseFreq=chan[i].std.arp+24;
} else {
chan[i].baseFreq=chan[i].note+chan[i].std.arp-12;
}
if (chan[i].baseFreq>255) chan[i].baseFreq=255;
if (chan[i].baseFreq<0) chan[i].baseFreq=0;
} else {
if (!chan[i].inPorta) {
if (chan[i].std.arpMode) {
chan[i].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(chan[i].std.arp+24)/12.0f)));
} else {
chan[i].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(chan[i].note+chan[i].std.arp-12)/12.0f)));
}
}
}
chan[i].freqChanged=true;
} else {
if (chan[i].std.arpMode && chan[i].std.finishedArp) {
chan[i].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(chan[i].note)/12.0f)));
chan[i].freqChanged=true;
}
}
if (chan[i].std.hadDuty) {
chan[i].duty=chan[i].std.duty;
DivInstrument* ins=parent->getIns(chan[i].ins);
if (i!=2) {
apu_wr_reg(0x4000+i*4,0x30|chan[i].outVol|((chan[i].duty&3)<<6));
}
}
if (chan[i].std.hadWave) {
if (chan[i].wave!=chan[i].std.wave) {
chan[i].wave=chan[i].std.wave;
if (i==2) {
if (!chan[i].keyOff) chan[i].keyOn=true;
}
}
}
if (chan[i].sweepChanged) {
chan[i].sweepChanged=false;
if (i==0) {
//rWrite(16+i*5,chan[i].sweep);
}
}
if (chan[i].freqChanged || chan[i].keyOn || chan[i].keyOff) {
DivInstrument* ins=parent->getIns(chan[i].ins);
if (i==3) { // noise
chan[i].freq=noiseTable[chan[i].baseFreq];
} else {
chan[i].freq=(chan[i].baseFreq*(ONE_SEMITONE-chan[i].pitch))/ONE_SEMITONE;
if (chan[i].freq>2047) chan[i].freq=2047;
}
if (chan[i].note>0x5d) chan[i].freq=0x01;
if (chan[i].keyOn) {
//rWrite(16+i*5+1,((chan[i].duty&3)<<6)|(63-(ins->gb.soundLen&63)));
//rWrite(16+i*5+2,((chan[i].vol<<4))|(ins->gb.envLen&7)|((ins->gb.envDir&1)<<3));
}
if (chan[i].keyOff) {
//rWrite(16+i*5+2,8);
if (i==2) { // triangle
apu_wr_reg(0x4000+i*4,0x00);
} else {
apu_wr_reg(0x4000+i*4,0x30);
}
}
if (i==3) { // noise
apu_wr_reg(0x4002+i*4,chan[i].freq);
apu_wr_reg(0x4003+i*4,0xf0);
} else {
apu_wr_reg(0x4002+i*4,chan[i].freq&0xff);
if ((chan[i].prevFreq>>8)!=(chan[i].freq>>8) || i==2) {
apu_wr_reg(0x4003+i*4,0xf8|(chan[i].freq>>8));
}
chan[i].prevFreq=chan[i].freq;
}
if (chan[i].keyOn) chan[i].keyOn=false;
if (chan[i].keyOff) chan[i].keyOff=false;
chan[i].freqChanged=false;
}
}
}
int DivPlatformNES::dispatch(DivCommand c) {
switch (c.cmd) {
case DIV_CMD_NOTE_ON:
if (c.chan==4) { // PCM
dacSample=c.value%12;
if (dacSample>=parent->song.sampleLen) {
dacSample=-1;
break;
}
dacPos=0;
dacPeriod=0;
dacRate=dacRates[parent->song.sample[dacSample]->rate];
break;
} else if (c.chan==3) { // noise
chan[c.chan].baseFreq=c.value;
} else {
chan[c.chan].baseFreq=round(FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
}
chan[c.chan].freqChanged=true;
chan[c.chan].note=c.value;
chan[c.chan].active=true;
chan[c.chan].keyOn=true;
chan[c.chan].std.init(parent->getIns(chan[c.chan].ins));
if (c.chan==2) {
apu_wr_reg(0x4000+c.chan*4,0xff);
} else {
apu_wr_reg(0x4000+c.chan*4,0x30|chan[c.chan].vol|((chan[c.chan].duty&3)<<6));
}
break;
case DIV_CMD_NOTE_OFF:
chan[c.chan].active=false;
chan[c.chan].keyOff=true;
chan[c.chan].std.init(NULL);
break;
case DIV_CMD_INSTRUMENT:
if (chan[c.chan].ins!=c.value) {
chan[c.chan].ins=c.value;
}
break;
case DIV_CMD_VOLUME:
if (chan[c.chan].vol!=c.value) {
chan[c.chan].vol=c.value;
if (!chan[c.chan].std.hasVol) {
chan[c.chan].outVol=c.value;
}
if (c.chan==2) {
apu_wr_reg(0x4000+c.chan*4,0xff);
} else {
apu_wr_reg(0x4000+c.chan*4,0x30|chan[c.chan].vol|((chan[c.chan].duty&3)<<6));
}
}
break;
case DIV_CMD_GET_VOLUME:
return chan[c.chan].vol;
break;
case DIV_CMD_PITCH:
chan[c.chan].pitch=c.value;
chan[c.chan].freqChanged=true;
break;
case DIV_CMD_NOTE_PORTA: {
int destFreq=round(FREQ_BASE/pow(2.0f,((float)c.value2/12.0f)));
bool return2=false;
if (destFreq>chan[c.chan].baseFreq) {
chan[c.chan].baseFreq+=c.value;
if (chan[c.chan].baseFreq>=destFreq) {
chan[c.chan].baseFreq=destFreq;
return2=true;
}
} else {
chan[c.chan].baseFreq-=c.value;
if (chan[c.chan].baseFreq<=destFreq) {
chan[c.chan].baseFreq=destFreq;
return2=true;
}
}
chan[c.chan].freqChanged=true;
if (return2) {
chan[c.chan].inPorta=false;
return 2;
}
break;
}
case DIV_CMD_STD_NOISE_MODE:
chan[c.chan].duty=c.value;
if (c.chan!=2) {
chan[c.chan].freqChanged=true;
}
break;
case DIV_CMD_PANNING: {
lastPan&=~(0x11<<c.chan);
if (c.value==0) c.value=0x11;
lastPan|=c.value<<c.chan;
break;
}
case DIV_CMD_LEGATO:
if (c.chan==3) break;
chan[c.chan].baseFreq=round(FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
chan[c.chan].freqChanged=true;
chan[c.chan].note=c.value;
break;
case DIV_CMD_PRE_PORTA:
chan[c.chan].std.init(parent->getIns(chan[c.chan].ins));
chan[c.chan].inPorta=c.value;
break;
case DIV_CMD_GET_VOLMAX:
return 15;
break;
case DIV_ALWAYS_SET_VOLUME:
return 1;
break;
default:
break;
}
return 1;
}
int DivPlatformNES::init(DivEngine* p, int channels, int sugRate) {
parent=p;
rate=1789773;
dacPeriod=0;
dacPos=0;
dacRate=0;
dacSample=-1;
init_nla_table(500,500);
apu_turn_on();
apu.addrSpace=new unsigned char[65536];
apu.cpu_cycles=0;
apu.cpu_opcode_cycle=0;
apu_wr_reg(0x4015,0x1f);
apu_wr_reg(0x4001,0x08);
apu_wr_reg(0x4005,0x08);
/*apu_wr_reg(0x4000,0x3f);
apu_wr_reg(0x4001,0x00);
apu_wr_reg(0x4002,0xff);
apu_wr_reg(0x4003,0x10);
apu_wr_reg(0x4004,0x3f);
apu_wr_reg(0x4005,0x00);
apu_wr_reg(0x4006,0xfe);
apu_wr_reg(0x4007,0x10);*/
lastPan=0xff;
return 5;
}

45
src/engine/platform/nes.h Normal file
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@ -0,0 +1,45 @@
#ifndef _APU_H
#define _APU_H
#include "../dispatch.h"
#include "../macroInt.h"
class DivPlatformNES: public DivDispatch {
struct Channel {
int freq, baseFreq, pitch, prevFreq;
unsigned char ins, note, duty, sweep;
bool active, insChanged, freqChanged, sweepChanged, keyOn, keyOff, inPorta;
signed char vol, outVol, wave;
DivMacroInt std;
Channel():
freq(0),
baseFreq(0),
pitch(0),
prevFreq(-1),
ins(-1),
note(0),
duty(0),
sweep(0),
active(false),
insChanged(true),
freqChanged(false),
sweepChanged(false),
keyOn(false),
keyOff(false),
inPorta(false),
vol(15),
wave(-1) {}
};
Channel chan[5];
int dacPeriod, dacRate, dacPos, dacSample;
unsigned char lastPan;
void updateWave();
public:
void acquire(int& l, int& r);
int dispatch(DivCommand c);
void tick();
int init(DivEngine* parent, int channels, int sugRate);
};
#endif

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@ -18,6 +18,10 @@ class DivPlatformPCE: public DivDispatch {
freq(0), freq(0),
baseFreq(0), baseFreq(0),
pitch(0), pitch(0),
dacPeriod(0),
dacRate(0),
dacPos(0),
dacSample(0),
ins(-1), ins(-1),
note(0), note(0),
pan(255), pan(255),

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@ -224,4 +224,5 @@ void apu_turn_on(void) {
// http://forums.nesdev.com/viewtopic.php?f=3&t=18278 // http://forums.nesdev.com/viewtopic.php?f=3&t=18278
DMC.length = 1; DMC.length = 1;
DMC.address_start = 0xC000; DMC.address_start = 0xC000;
apu.odd_cycle = 0;
} }

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@ -27,10 +27,6 @@ enum dmc_types_of_dma { DMC_NORMAL, DMC_CPU_WRITE, DMC_R4014, DMC_NNL_DMA };
enum apu_channels { APU_S1, APU_S2, APU_TR, APU_NS, APU_DMC, APU_EXTRA, APU_MASTER }; enum apu_channels { APU_S1, APU_S2, APU_TR, APU_NS, APU_DMC, APU_EXTRA, APU_MASTER };
enum apu_mode { APU_60HZ, APU_48HZ }; enum apu_mode { APU_60HZ, APU_48HZ };
int cpu_cycles;
int cpu_opcode_cycle;
unsigned char* addrSpace;
#define apu_pre_amp 1.4f #define apu_pre_amp 1.4f
/* length counter */ /* length counter */
@ -211,14 +207,14 @@ unsigned char* addrSpace;
break;\ break;\
}\ }\
{\ {\
DMC.buffer = addrSpace[DMC.address];\ DMC.buffer = apu.addrSpace[DMC.address];\
}\ }\
/* incremento gli hwtick da compiere */\ /* incremento gli hwtick da compiere */\
if (hwtick) { hwtick[0] += tick; }\ if (hwtick) { hwtick[0] += tick; }\
/* e naturalmente incremento anche quelli eseguiti dall'opcode */\ /* e naturalmente incremento anche quelli eseguiti dall'opcode */\
cpu_cycles += tick;\ apu.cpu_cycles += tick;\
/* salvo a che ciclo dell'istruzione avviene il dma */\ /* salvo a che ciclo dell'istruzione avviene il dma */\
DMC.dma_cycle = cpu_opcode_cycle;\ DMC.dma_cycle = apu.cpu_opcode_cycle;\
/* il DMC non e' vuoto */\ /* il DMC non e' vuoto */\
DMC.empty = FALSE;\ DMC.empty = FALSE;\
if (++DMC.address > 0xFFFF) {\ if (++DMC.address > 0xFFFF) {\
@ -340,7 +336,7 @@ unsigned char* addrSpace;
}\ }\
} }
#define _apu_channel_volume_adjust(ch, index)\ #define _apu_channel_volume_adjust(ch, index)\
((ch * cfg->apu.channel[index]) * ch_gain_ptnd(index)) ((ch))
#define s1_out\ #define s1_out\
_apu_channel_volume_adjust(S1.output, APU_S1) _apu_channel_volume_adjust(S1.output, APU_S1)
#define s2_out\ #define s2_out\
@ -370,6 +366,11 @@ typedef struct _apu {
BYTE DMC; BYTE DMC;
SWORD cycles; SWORD cycles;
int cpu_cycles;
int cpu_opcode_cycle;
unsigned char* addrSpace;
BYTE odd_cycle;
/* ------------------------------------------------------- */ /* ------------------------------------------------------- */
/* questi valori non e' necessario salvarli nei savestates */ /* questi valori non e' necessario salvarli nei savestates */
/* ------------------------------------------------------- */ /* ------------------------------------------------------- */

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@ -0,0 +1,317 @@
/*
* Copyright (C) 2010-2019 Fabio Cavallo (aka FHorse)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifndef CPU_INLINE_H_
#define CPU_INLINE_H_
#include <stdlib.h>
#include "apu.h"
#define mod_cycles_op(op, vl) cpu.cycles op vl
#define r2006_during_rendering()\
if (!ppu.vblank && r2001.visible && (ppu.frame_y > ppu_sclines.vint) &&\
(ppu.screen_y < SCR_LINES)) {\
_r2006_during_rendering()\
} else {\
r2006.value += r2000.r2006_inc;\
}
#define _r2006_during_rendering()\
r2006_inc()\
if ((r2006.value & 0x1F) == 0x1F) {\
r2006.value ^= 0x41F;\
} else {\
r2006.value++;\
}
INLINE static void apu_wr_reg(WORD address, BYTE value) {
if (!(address & 0x0010)) {
/* -------------------- square 1 --------------------*/
if (address <= 0x4003) {
if (address == 0x4000) {
square_reg0(S1);
return;
}
if (address == 0x4001) {
square_reg1(S1);
sweep_silence(S1)
return;
}
if (address == 0x4002) {
square_reg2(S1);
sweep_silence(S1)
return;
}
if (address == 0x4003) {
square_reg3(S1);
sweep_silence(S1)
return;
}
return;
}
/* -------------------- square 2 --------------------*/
if (address <= 0x4007) {
if (address == 0x4004) {
square_reg0(S2);
return;
}
if (address == 0x4005) {
square_reg1(S2);
sweep_silence(S2)
return;
}
if (address == 0x4006) {
square_reg2(S2);
sweep_silence(S2)
return;
}
if (address == 0x4007) {
square_reg3(S2);
sweep_silence(S2)
return;
}
return;
}
/* -------------------- triangle --------------------*/
if (address <= 0x400B) {
if (address == 0x4008) {
/* length counter */
/*
* il triangle ha una posizione diversa per il
* flag LCHalt.
*/
TR.length.halt = value & 0x80;
/* linear counter */
TR.linear.reload = value & 0x7F;
return;
}
if (address == 0x400A) {
/* timer (low 8 bits) */
TR.timer = (TR.timer & 0x0700) | value;
return;
}
if (address == 0x400B) {
/* length counter */
/*
* se non disabilitato, una scrittura in
* questo registro, carica immediatamente il
* length counter del canale, tranne nel caso
* in cui la scrittura avvenga nello stesso
* momento del clock di un length counter e
* con il length diverso da zero.
*/
if (TR.length.enabled && !(apu.length_clocked && TR.length.value)) {
TR.length.value = length_table[value >> 3];
}
/* timer (high 3 bits) */
TR.timer = (TR.timer & 0x00FF) | ((value & 0x07) << 8);
/*
* scrivendo in questo registro si setta
* automaticamente l'halt flag del triangle.
*/
TR.linear.halt = TRUE;
return;
}
return;
}
/* --------------------- noise ----------------------*/
if (address <= 0x400F) {
if (address == 0x400C) {
NS.length.halt = value & 0x20;
/* envelope */
NS.envelope.constant_volume = value & 0x10;
NS.envelope.divider = value & 0x0F;
return;
}
if (address == 0x400E) {
NS.mode = value & 0x80;
NS.timer = value & 0x0F;
return;
}
if (address == 0x400F) {
/*
* se non disabilitato, una scrittura in
* questo registro, carica immediatamente il
* length counter del canale, tranne nel caso
* in cui la scrittura avvenga nello stesso
* momento del clock di un length counter e
* con il length diverso da zero.
*/
if (NS.length.enabled && !(apu.length_clocked && NS.length.value)) {
NS.length.value = length_table[value >> 3];
}
/* envelope */
NS.envelope.enabled = TRUE;
return;
}
return;
}
return;
} else {
/* ---------------------- DMC -----------------------*/
if (address <= 0x4013) {
if (address == 0x4010) {
DMC.irq_enabled = value & 0x80;
/* se l'irq viene disabilitato allora... */
if (!DMC.irq_enabled) {
/* ...azzero l'interrupt flag del DMC */
r4015.value &= 0x7F;
}
DMC.loop = value & 0x40;
DMC.rate_index = value & 0x0F;
return;
}
if (address == 0x4011) {
BYTE save = DMC.counter;
value &= 0x7F;
/*
* questa lo faccio perche' in alcuni giochi come Batman,
* Ninja Gaiden 3, Castlevania II ed altri, producono
* un popping del suono fastidioso;
* from Fceu doc:
* Why do some games make a popping sound (Batman, Ninja Gaiden 3,
* Castlevania II etc.)? These games do a very crude drum imitation
* by causing a large jump in the output level for a short period of
* time via the register at $4011. The analog filters on a real
* Famicom make it sound decent(better). I have not completely
* emulated these filters.
* (Xodnizel)
*/
if (r4011.frames > 1) {
r4011.output = (value - save) >> 3;
DMC.counter = DMC.output = save + r4011.output;
} else {
DMC.counter = DMC.output = value;
}
apu.clocked = TRUE;
r4011.cycles = r4011.frames = 0;
r4011.value = value;
return;
}
if (address == 0x4012) {
DMC.address_start = (value << 6) | 0xC000;
return;
}
if (address == 0x4013) {
/* sample length */
DMC.length = (value << 4) | 0x01;
return;
}
return;
}
/* --------------------------------------------------*/
if (address == 0x4015) {
/*
* 76543210
* || |||||
* || ||||+- Pulse channel 1's length counter enabled flag
* || |||+-- Pulse channel 2's length counter enabled flag
* || ||+--- Triangle channel's length counter enabled flag
* || |+---- Noise channel's length counter enabled flag
* || +----- If clear, the DMC's bytes remaining is set to 0,
* || otherwise the DMC sample is restarted only if the
* || DMC's bytes remaining is 0
* |+------- Frame interrupt flag
* +-------- DMC interrupt flag
*/
/*
* dopo la write il bit 7 (dmc flag) deve
* essere azzerato mentre lascio inalterati
* i bit 5 e 6.
*/
r4015.value = (r4015.value & 0x60) | (value & 0x1F);
/*
* quando il flag di abilitazione del length
* counter di ogni canale e' a 0, il counter
* dello stesso canale e' immediatamente azzerato.
*/
if (!(S1.length.enabled = r4015.value & 0x01)) {
S1.length.value = 0;
}
if (!(S2.length.enabled = r4015.value & 0x02)) {
S2.length.value = 0;
}
if (!(TR.length.enabled = r4015.value & 0x04)) {
TR.length.value = 0;
}
if (!(NS.length.enabled = r4015.value & 0x08)) {
NS.length.value = 0;
}
/*
* se il bit 4 e' 0 allora devo azzerare i bytes
* rimanenti del DMC, alrimenti devo riavviare
* la lettura dei sample DMC solo nel caso che
* in cui i bytes rimanenti siano a 0.
*/
if (!(r4015.value & 0x10)) {
DMC.remain = 0;
DMC.empty = TRUE;
} else if (!DMC.remain) {
DMC.remain = DMC.length;
DMC.address = DMC.address_start;
}
return;
}
#if defined (VECCHIA_GESTIONE_JITTER)
if (address == 0x4017) {
/* APU frame counter */
r4017.jitter.value = value;
/*
* nell'2A03 se la scrittura del $4017 avviene
* in un ciclo pari, allora l'effettiva modifica
* avverra' nel ciclo successivo.
*/
if (cpu.odd_cycle) {
r4017.jitter.delay = TRUE;
} else {
r4017.jitter.delay = FALSE;
r4017_jitter();
}
return;
}
#else
if (address == 0x4017) {
/* APU frame counter */
r4017.jitter.value = value;
/*
* nell'2A03 se la scrittura del $4017 avviene
* in un ciclo pari, allora l'effettiva modifica
* avverra' nel ciclo successivo.
*/
if (apu.odd_cycle) {
r4017.jitter.delay = TRUE;
} else {
r4017.jitter.delay = FALSE;
r4017_jitter(1)
r4017_reset_frame()
}
return;
}
#endif
}
#if defined (DEBUG)
//fprintf(stderr, "Alert: Attempt to write APU port %04X\n", address);
#endif
return;
}
#endif /* CPU_INLINE_H_ */