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VERA: bring up actual emulation core

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This commit is contained in:
tildearrow 2022-03-10 15:51:27 -05:00
parent 587fecd11d
commit 9bd15bd513
7 changed files with 303 additions and 3 deletions
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2
CMakeLists.txt
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@ -234,6 +234,8 @@ src/engine/platform/sound/gb/apu.c
src/engine/platform/sound/gb/timing.c src/engine/platform/sound/gb/timing.c
src/engine/platform/sound/pce_psg.cpp src/engine/platform/sound/pce_psg.cpp
src/engine/platform/sound/nes/apu.c src/engine/platform/sound/nes/apu.c
src/engine/platform/sound/vera_psg.c
src/engine/platform/sound/vera_pcm.c
src/engine/platform/sound/c64/sid.cc src/engine/platform/sound/c64/sid.cc
src/engine/platform/sound/c64/voice.cc src/engine/platform/sound/c64/voice.cc

130
src/engine/platform/sound/vera_pcm.c Normal file
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@ -0,0 +1,130 @@
// Commander X16 Emulator
// Copyright (c) 2020 Frank van den Hoef
// All rights reserved. License: 2-clause BSD
#include "vera_pcm.h"
#include <stdio.h>
static uint8_t volume_lut[16] = {0, 1, 2, 3, 4, 5, 6, 8, 11, 14, 18, 23, 30, 38, 49, 64};
static void
fifo_reset(struct VERA_PCM* pcm)
{
pcm->fifo_wridx = 0;
pcm->fifo_rdidx = 0;
pcm->fifo_cnt = 0;
}
void
pcm_reset(struct VERA_PCM* pcm)
{
fifo_reset(pcm);
pcm->ctrl = 0;
pcm->rate = 0;
pcm->cur_l = 0;
pcm->cur_r = 0;
pcm->phase = 0;
}
void
pcm_write_ctrl(struct VERA_PCM* pcm, uint8_t val)
{
if (val & 0x80) {
fifo_reset(pcm);
}
pcm->ctrl = val & 0x3F;
}
uint8_t
pcm_read_ctrl(struct VERA_PCM* pcm)
{
uint8_t result = pcm->ctrl;
if (pcm->fifo_cnt == sizeof(pcm->fifo)) {
result |= 0x80;
}
return result;
}
void
pcm_write_rate(struct VERA_PCM* pcm, uint8_t val)
{
pcm->rate = val;
}
uint8_t
pcm_read_rate(struct VERA_PCM* pcm)
{
return pcm->rate;
}
void
pcm_write_fifo(struct VERA_PCM* pcm, uint8_t val)
{
if (pcm->fifo_cnt < sizeof(pcm->fifo)) {
pcm->fifo[pcm->fifo_wridx++] = val;
if (pcm->fifo_wridx == sizeof(pcm->fifo)) {
pcm->fifo_wridx = 0;
}
pcm->fifo_cnt++;
}
}
static uint8_t
read_fifo(struct VERA_PCM* pcm)
{
if (pcm->fifo_cnt == 0) {
return 0;
}
uint8_t result = pcm->fifo[pcm->fifo_rdidx++];
if (pcm->fifo_rdidx == sizeof(pcm->fifo)) {
pcm->fifo_rdidx = 0;
}
pcm->fifo_cnt--;
return result;
}
bool
pcm_is_fifo_almost_empty(struct VERA_PCM* pcm)
{
return pcm->fifo_cnt < 1024;
}
void
pcm_render(struct VERA_PCM* pcm, int16_t* buf_l, int16_t* buf_r, unsigned num_samples)
{
while (num_samples--) {
uint8_t old_phase = pcm->phase;
pcm->phase += pcm->rate;
if ((old_phase & 0x80) != (pcm->phase & 0x80)) {
switch ((pcm->ctrl >> 4) & 3) {
case 0: { // mono 8-bit
pcm->cur_l = (int16_t)read_fifo(pcm) << 8;
pcm->cur_r = pcm->cur_l;
break;
}
case 1: { // stereo 8-bit
pcm->cur_l = read_fifo(pcm) << 8;
pcm->cur_r = read_fifo(pcm) << 8;
break;
}
case 2: { // mono 16-bit
pcm->cur_l = read_fifo(pcm);
pcm->cur_l |= read_fifo(pcm) << 8;
pcm->cur_r = pcm->cur_l;
break;
}
case 3: { // stereo 16-bit
pcm->cur_l = read_fifo(pcm);
pcm->cur_l |= read_fifo(pcm) << 8;
pcm->cur_r = read_fifo(pcm);
pcm->cur_r |= read_fifo(pcm) << 8;
break;
}
}
}
*(buf_l++) = ((int)pcm->cur_l * (int)volume_lut[pcm->ctrl & 0xF]) >> 6;
*(buf_r++) = ((int)pcm->cur_r * (int)volume_lut[pcm->ctrl & 0xF]) >> 6;
}
}

31
src/engine/platform/sound/vera_pcm.h Normal file
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@ -0,0 +1,31 @@
// Commander X16 Emulator
// Copyright (c) 2020 Frank van den Hoef
// All rights reserved. License: 2-clause BSD
#pragma once
#include <stdint.h>
#include <stdbool.h>
struct VERA_PCM {
uint8_t fifo[4096 - 1]; // Actual hardware FIFO is 4kB, but you can only use 4095 bytes.
unsigned fifo_wridx;
unsigned fifo_rdidx;
unsigned fifo_cnt;
uint8_t ctrl;
uint8_t rate;
int16_t cur_l, cur_r;
uint8_t phase;
};
void pcm_reset(struct VERA_PCM* pcm);
void pcm_write_ctrl(struct VERA_PCM* pcm, uint8_t val);
uint8_t pcm_read_ctrl(struct VERA_PCM* pcm);
void pcm_write_rate(struct VERA_PCM* pcm, uint8_t val);
uint8_t pcm_read_rate(struct VERA_PCM* pcm);
void pcm_write_fifo(struct VERA_PCM* pcm, uint8_t val);
void pcm_render(struct VERA_PCM* pcm, int16_t* buf_l, int16_t* buf_r, unsigned num_samples);
bool pcm_is_fifo_almost_empty(struct VERA_PCM* pcm);

98
src/engine/platform/sound/vera_psg.c Normal file
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@ -0,0 +1,98 @@
// Commander X16 Emulator
// Copyright (c) 2020 Frank van den Hoef
// All rights reserved. License: 2-clause BSD
#include "vera_psg.h"
#include <stdlib.h>
#include <string.h>
enum waveform {
WF_PULSE = 0,
WF_SAWTOOTH,
WF_TRIANGLE,
WF_NOISE,
};
static uint8_t volume_lut[64] = {0, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 6, 6, 7, 7, 7, 8, 8, 9, 9, 10, 11, 11, 12, 13, 14, 14, 15, 16, 17, 18, 19, 21, 22, 23, 25, 26, 28, 29, 31, 33, 35, 37, 39, 42, 44, 47, 50, 52, 56, 59, 63};
void
psg_reset(struct VERA_PSG* psg)
{
memset(psg->channels, 0, sizeof(psg->channels));
}
void
psg_writereg(struct VERA_PSG* psg, uint8_t reg, uint8_t val)
{
reg &= 0x3f;
int ch = reg / 4;
int idx = reg & 3;
switch (idx) {
case 0: psg->channels[ch].freq = (psg->channels[ch].freq & 0xFF00) | val; break;
case 1: psg->channels[ch].freq = (psg->channels[ch].freq & 0x00FF) | (val << 8); break;
case 2: {
psg->channels[ch].right = (val & 0x80) != 0;
psg->channels[ch].left = (val & 0x40) != 0;
psg->channels[ch].volume = volume_lut[val & 0x3F];
break;
}
case 3: {
psg->channels[ch].pw = val & 0x3F;
psg->channels[ch].waveform = val >> 6;
break;
}
}
}
static inline void
render(struct VERA_PSG* psg, int16_t *left, int16_t *right)
{
int l = 0;
int r = 0;
for (int i = 0; i < 16; i++) {
struct VERAChannel *ch = &psg->channels[i];
unsigned new_phase = (ch->phase + ch->freq) & 0x1FFFF;
if ((ch->phase & 0x10000) != (new_phase & 0x10000)) {
ch->noiseval = rand() & 63;
}
ch->phase = new_phase;
uint8_t v = 0;
switch (ch->waveform) {
case WF_PULSE: v = (ch->phase >> 10) > ch->pw ? 0 : 63; break;
case WF_SAWTOOTH: v = ch->phase >> 11; break;
case WF_TRIANGLE: v = (ch->phase & 0x10000) ? (~(ch->phase >> 10) & 0x3F) : ((ch->phase >> 10) & 0x3F); break;
case WF_NOISE: v = ch->noiseval; break;
}
int8_t sv = (v ^ 0x20);
if (sv & 0x20) {
sv |= 0xC0;
}
int val = (int)sv * (int)ch->volume;
if (ch->left) {
l += val;
}
if (ch->right) {
r += val;
}
}
*left = l;
*right = r;
}
void
psg_render(struct VERA_PSG* psg, int16_t *buf, unsigned num_samples)
{
while (num_samples--) {
render(psg, &buf[0], &buf[1]);
buf += 2;
}
}

27
src/engine/platform/sound/vera_psg.h Normal file
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@ -0,0 +1,27 @@
// Commander X16 Emulator
// Copyright (c) 2020 Frank van den Hoef
// All rights reserved. License: 2-clause BSD
#pragma once
#include <stdint.h>
#include <stdbool.h>
struct VERAChannel {
uint16_t freq;
uint8_t volume;
bool left, right;
uint8_t pw;
uint8_t waveform;
unsigned phase;
uint8_t noiseval;
};
struct VERA_PSG {
struct VERAChannel channels[16];
};
void psg_reset(struct VERA_PSG* psg);
void psg_writereg(struct VERA_PSG* psg, uint8_t reg, uint8_t val);
void psg_render(struct VERA_PSG* psg, int16_t *buf, unsigned num_samples);

11
src/engine/platform/vera.cpp
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@ -22,6 +22,9 @@
#include <string.h> #include <string.h>
#include <math.h> #include <math.h>
#include "sound/vera_psg.h"
#include "sound/vera_pcm.h"
#define rWrite(c,a,d) {regPool[(c)*4+(a)]=(d);} #define rWrite(c,a,d) {regPool[(c)*4+(a)]=(d);}
#define rWriteLo(c,a,d) rWrite(c,a,(regPool[(c)*4+(a)]&(~0x3f))|((d)&0x3f)) #define rWriteLo(c,a,d) rWrite(c,a,(regPool[(c)*4+(a)]&(~0x3f))|((d)&0x3f))
#define rWriteHi(c,a,d) rWrite(c,a,(regPool[(c)*4+(a)]&(~0xc0))|(((d)<<6)&0xc0)) #define rWriteHi(c,a,d) rWrite(c,a,(regPool[(c)*4+(a)]&(~0xc0))|(((d)<<6)&0xc0))
@ -69,8 +72,6 @@ void DivPlatformVERA::reset() {
} }
chan[16].vol=15; chan[16].vol=15;
chan[16].pan=3; chan[16].pan=3;
noiseState=1;
noiseOut=0;
} }
int DivPlatformVERA::calcNoteFreq(int ch, int note) { int DivPlatformVERA::calcNoteFreq(int ch, int note) {
@ -321,6 +322,8 @@ int DivPlatformVERA::init(DivEngine* p, int channels, int sugRate, unsigned int
isMuted[i]=false; isMuted[i]=false;
} }
parent=p; parent=p;
psg=new struct VERA_PSG;
pcm=new struct VERA_PCM;
dumpWrites=false; dumpWrites=false;
skipRegisterWrites=false; skipRegisterWrites=false;
chipClock=25000000; chipClock=25000000;
@ -329,5 +332,9 @@ int DivPlatformVERA::init(DivEngine* p, int channels, int sugRate, unsigned int
return 17; return 17;
} }
void DivPlatformVERA::quit() {
delete psg;
delete pcm;
}
DivPlatformVERA::~DivPlatformVERA() { DivPlatformVERA::~DivPlatformVERA() {
} }

7
src/engine/platform/vera.h
View file

@ -23,6 +23,9 @@
#include "../instrument.h" #include "../instrument.h"
#include "../macroInt.h" #include "../macroInt.h"
struct VERA_PSG;
struct VERA_PCM;
class DivPlatformVERA: public DivDispatch { class DivPlatformVERA: public DivDispatch {
protected: protected:
struct Channel { struct Channel {
@ -46,8 +49,9 @@ class DivPlatformVERA: public DivDispatch {
}; };
Channel chan[17]; Channel chan[17];
bool isMuted[17]; bool isMuted[17];
unsigned noiseState, noiseOut;
unsigned char regPool[66]; unsigned char regPool[66];
struct VERA_PSG* psg;
struct VERA_PCM* pcm;
int calcNoteFreq(int ch, int note); int calcNoteFreq(int ch, int note);
friend void putDispatchChan(void*,int,int); friend void putDispatchChan(void*,int,int);
@ -68,6 +72,7 @@ class DivPlatformVERA: public DivDispatch {
const char** getRegisterSheet(); const char** getRegisterSheet();
const char* getEffectName(unsigned char effect); const char* getEffectName(unsigned char effect);
int init(DivEngine* parent, int channels, int sugRate, unsigned int flags); int init(DivEngine* parent, int channels, int sugRate, unsigned int flags);
void quit();
~DivPlatformVERA(); ~DivPlatformVERA();
}; };
#endif #endif