From d85ae21b2f06a85cc9f4b867ebd849367719a153 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Wed, 18 Dec 2019 19:28:41 -0500
Subject: [PATCH 1/2] Adds an explicit declaration of chip type to all AY
users.
---
Components/AY38910/AY38910.cpp | 4 ++--
Components/AY38910/AY38910.hpp | 9 ++++++++-
Machines/AmstradCPC/AmstradCPC.cpp | 2 +-
Machines/Atari/ST/AtariST.cpp | 2 +-
Machines/ColecoVision/ColecoVision.cpp | 2 +-
Machines/MSX/MSX.cpp | 2 +-
Machines/Oric/Oric.cpp | 2 +-
Machines/ZX8081/ZX8081.cpp | 2 +-
8 files changed, 16 insertions(+), 9 deletions(-)
diff --git a/Components/AY38910/AY38910.cpp b/Components/AY38910/AY38910.cpp
index fab7e94b3..9266baadc 100644
--- a/Components/AY38910/AY38910.cpp
+++ b/Components/AY38910/AY38910.cpp
@@ -12,8 +12,8 @@
using namespace GI::AY38910;
-AY38910::AY38910(Concurrency::DeferringAsyncTaskQueue &task_queue) : task_queue_(task_queue) {
- // set up envelope lookup tables
+AY38910::AY38910(Personality personality, Concurrency::DeferringAsyncTaskQueue &task_queue) : task_queue_(task_queue) {
+ // Set up envelope lookup tables.
for(int c = 0; c < 16; c++) {
for(int p = 0; p < 32; p++) {
switch(c) {
diff --git a/Components/AY38910/AY38910.hpp b/Components/AY38910/AY38910.hpp
index 222d11c74..1eae0cefe 100644
--- a/Components/AY38910/AY38910.hpp
+++ b/Components/AY38910/AY38910.hpp
@@ -52,6 +52,13 @@ enum ControlLines {
BDIR = (1 << 2)
};
+enum class Personality {
+ /// Provides 16 volume levels to envelopes.
+ AY38910,
+ /// Provides 32 volume levels to envelopes.
+ YM2149F
+};
+
/*!
Provides emulation of an AY-3-8910 / YM2149, which is a three-channel sound chip with a
noise generator and a volume envelope generator, which also provides two bidirectional
@@ -60,7 +67,7 @@ enum ControlLines {
class AY38910: public ::Outputs::Speaker::SampleSource {
public:
/// Creates a new AY38910.
- AY38910(Concurrency::DeferringAsyncTaskQueue &task_queue);
+ AY38910(Personality, Concurrency::DeferringAsyncTaskQueue &);
/// Sets the value the AY would read from its data lines if it were not outputting.
void set_data_input(uint8_t r);
diff --git a/Machines/AmstradCPC/AmstradCPC.cpp b/Machines/AmstradCPC/AmstradCPC.cpp
index bf869cf12..3b707348e 100644
--- a/Machines/AmstradCPC/AmstradCPC.cpp
+++ b/Machines/AmstradCPC/AmstradCPC.cpp
@@ -124,7 +124,7 @@ class InterruptTimer {
class AYDeferrer {
public:
/// Constructs a new AY instance and sets its clock rate.
- AYDeferrer() : ay_(audio_queue_), speaker_(ay_) {
+ AYDeferrer() : ay_(GI::AY38910::Personality::AY38910, audio_queue_), speaker_(ay_) {
speaker_.set_input_rate(1000000);
}
diff --git a/Machines/Atari/ST/AtariST.cpp b/Machines/Atari/ST/AtariST.cpp
index a9e8697c9..447c20ce5 100644
--- a/Machines/Atari/ST/AtariST.cpp
+++ b/Machines/Atari/ST/AtariST.cpp
@@ -63,7 +63,7 @@ class ConcreteMachine:
mc68000_(*this),
keyboard_acia_(Cycles(500000)),
midi_acia_(Cycles(500000)),
- ay_(audio_queue_),
+ ay_(GI::AY38910::Personality::YM2149F, audio_queue_),
speaker_(ay_),
ikbd_(keyboard_acia_->transmit, keyboard_acia_->receive) {
set_clock_rate(CLOCK_RATE);
diff --git a/Machines/ColecoVision/ColecoVision.cpp b/Machines/ColecoVision/ColecoVision.cpp
index c3386d633..965cc7604 100644
--- a/Machines/ColecoVision/ColecoVision.cpp
+++ b/Machines/ColecoVision/ColecoVision.cpp
@@ -123,7 +123,7 @@ class ConcreteMachine:
z80_(*this),
vdp_(TI::TMS::TMS9918A),
sn76489_(TI::SN76489::Personality::SN76489, audio_queue_, sn76489_divider),
- ay_(audio_queue_),
+ ay_(GI::AY38910::Personality::AY38910, audio_queue_),
mixer_(sn76489_, ay_),
speaker_(mixer_) {
speaker_.set_input_rate(3579545.0f / static_cast<float>(sn76489_divider));
diff --git a/Machines/MSX/MSX.cpp b/Machines/MSX/MSX.cpp
index bed05c068..5997cb0b1 100644
--- a/Machines/MSX/MSX.cpp
+++ b/Machines/MSX/MSX.cpp
@@ -154,7 +154,7 @@ class ConcreteMachine:
z80_(*this),
vdp_(TI::TMS::TMS9918A),
i8255_(i8255_port_handler_),
- ay_(audio_queue_),
+ ay_(GI::AY38910::Personality::AY38910, audio_queue_),
audio_toggle_(audio_queue_),
scc_(audio_queue_),
mixer_(ay_, audio_toggle_, scc_),
diff --git a/Machines/Oric/Oric.cpp b/Machines/Oric/Oric.cpp
index 158acc11e..3b7aca12e 100644
--- a/Machines/Oric/Oric.cpp
+++ b/Machines/Oric/Oric.cpp
@@ -213,7 +213,7 @@ template <Analyser::Static::Oric::Target::DiskInterface disk_interface> class Co
ConcreteMachine(const Analyser::Static::Oric::Target &target, const ROMMachine::ROMFetcher &rom_fetcher) :
m6502_(*this),
video_output_(ram_),
- ay8910_(audio_queue_),
+ ay8910_(GI::AY38910::Personality::AY38910, audio_queue_),
speaker_(ay8910_),
via_port_handler_(audio_queue_, ay8910_, speaker_, tape_player_, keyboard_),
via_(via_port_handler_),
diff --git a/Machines/ZX8081/ZX8081.cpp b/Machines/ZX8081/ZX8081.cpp
index 024601e41..c06bd8d10 100644
--- a/Machines/ZX8081/ZX8081.cpp
+++ b/Machines/ZX8081/ZX8081.cpp
@@ -69,7 +69,7 @@ template<bool is_zx81> class ConcreteMachine:
ConcreteMachine(const Analyser::Static::ZX8081::Target &target, const ROMMachine::ROMFetcher &rom_fetcher) :
z80_(*this),
tape_player_(ZX8081ClockRate),
- ay_(audio_queue_),
+ ay_(GI::AY38910::Personality::AY38910, audio_queue_),
speaker_(ay_) {
set_clock_rate(ZX8081ClockRate);
speaker_.set_input_rate(static_cast<float>(ZX8081ClockRate) / 2.0f);
From 206ab380c70460c57d3b1fd7e984baab5ffc70db Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Wed, 18 Dec 2019 22:03:02 -0500
Subject: [PATCH 2/2] Introduces double-resolution envelopes for the Atari ST.
---
Components/AY38910/AY38910.cpp | 78 +++++++++++++++++++++-------------
Components/AY38910/AY38910.hpp | 6 +--
2 files changed, 52 insertions(+), 32 deletions(-)
diff --git a/Components/AY38910/AY38910.cpp b/Components/AY38910/AY38910.cpp
index 9266baadc..30e5ddc46 100644
--- a/Components/AY38910/AY38910.cpp
+++ b/Components/AY38910/AY38910.cpp
@@ -13,44 +13,55 @@
using namespace GI::AY38910;
AY38910::AY38910(Personality personality, Concurrency::DeferringAsyncTaskQueue &task_queue) : task_queue_(task_queue) {
+ // Don't use the low bit of the envelope position if this is an AY.
+ envelope_position_mask_ |= personality == Personality::AY38910;
+
// Set up envelope lookup tables.
for(int c = 0; c < 16; c++) {
- for(int p = 0; p < 32; p++) {
+ for(int p = 0; p < 64; p++) {
switch(c) {
case 0: case 1: case 2: case 3: case 9:
- envelope_shapes_[c][p] = (p < 16) ? (p^0xf) : 0;
- envelope_overflow_masks_[c] = 0x1f;
+ /* Envelope: \____ */
+ envelope_shapes_[c][p] = (p < 32) ? (p^0x1f) : 0;
+ envelope_overflow_masks_[c] = 0x3f;
break;
case 4: case 5: case 6: case 7: case 15:
- envelope_shapes_[c][p] = (p < 16) ? p : 0;
- envelope_overflow_masks_[c] = 0x1f;
+ /* Envelope: /____ */
+ envelope_shapes_[c][p] = (p < 32) ? p : 0;
+ envelope_overflow_masks_[c] = 0x3f;
break;
case 8:
- envelope_shapes_[c][p] = (p & 0xf) ^ 0xf;
+ /* Envelope: \\\\\\\\ */
+ envelope_shapes_[c][p] = (p & 0x1f) ^ 0x1f;
envelope_overflow_masks_[c] = 0x00;
break;
case 12:
- envelope_shapes_[c][p] = (p & 0xf);
+ /* Envelope: //////// */
+ envelope_shapes_[c][p] = (p & 0x1f);
envelope_overflow_masks_[c] = 0x00;
break;
case 10:
- envelope_shapes_[c][p] = (p & 0xf) ^ ((p < 16) ? 0xf : 0x0);
+ /* Envelope: \/\/\/\/ */
+ envelope_shapes_[c][p] = (p & 0x1f) ^ ((p < 32) ? 0x1f : 0x0);
envelope_overflow_masks_[c] = 0x00;
break;
case 14:
- envelope_shapes_[c][p] = (p & 0xf) ^ ((p < 16) ? 0x0 : 0xf);
+ /* Envelope: /\/\/\/\ */
+ envelope_shapes_[c][p] = (p & 0x1f) ^ ((p < 32) ? 0x0 : 0x1f);
envelope_overflow_masks_[c] = 0x00;
break;
case 11:
- envelope_shapes_[c][p] = (p < 16) ? (p^0xf) : 0xf;
- envelope_overflow_masks_[c] = 0x1f;
+ /* Envelope: \------ (if - is high) */
+ envelope_shapes_[c][p] = (p < 32) ? (p^0x1f) : 0x1f;
+ envelope_overflow_masks_[c] = 0x3f;
break;
case 13:
- envelope_shapes_[c][p] = (p < 16) ? p : 0xf;
- envelope_overflow_masks_[c] = 0x1f;
+ /* Envelope: /------- */
+ envelope_shapes_[c][p] = (p < 32) ? p : 0x1f;
+ envelope_overflow_masks_[c] = 0x3f;
break;
}
}
@@ -63,16 +74,24 @@ void AY38910::set_sample_volume_range(std::int16_t range) {
// set up volume lookup table
const float max_volume = static_cast<float>(range) / 3.0f; // As there are three channels.
const float root_two = sqrtf(2.0f);
- for(int v = 0; v < 16; v++) {
- volumes_[v] = static_cast<int>(max_volume / powf(root_two, static_cast<float>(v ^ 0xf)));
+ for(int v = 0; v < 32; v++) {
+ volumes_[v] = int(max_volume / powf(root_two, float(v ^ 0x1f) / 2.0f));
}
- volumes_[0] = 0;
evaluate_output_volume();
}
void AY38910::get_samples(std::size_t number_of_samples, int16_t *target) {
+ // Note on structure below: the real AY has a built-in divider of 8
+ // prior to applying its tone and noise dividers. But the YM fills the
+ // same total periods for noise and tone with double-precision envelopes.
+ // Therefore this class implements a divider of 4 and doubles the tone
+ // and noise periods. The envelope ticks along at the divide-by-four rate,
+ // but if this is an AY rather than a YM then its lowest bit is forced to 1,
+ // matching the YM datasheet's depiction of envelope level 31 as equal to
+ // programmatic volume 15, envelope level 29 as equal to programmatic 14, etc.
+
std::size_t c = 0;
- while((master_divider_&7) && c < number_of_samples) {
+ while((master_divider_&3) && c < number_of_samples) {
target[c] = output_volume_;
master_divider_++;
c++;
@@ -83,49 +102,49 @@ void AY38910::get_samples(std::size_t number_of_samples, int16_t *target) {
if(tone_counters_[c]) tone_counters_[c]--;\
else {\
tone_outputs_[c] ^= 1;\
- tone_counters_[c] = tone_periods_[c];\
+ tone_counters_[c] = tone_periods_[c] << 1;\
}
- // update the tone channels
+ // Update the tone channels.
step_channel(0);
step_channel(1);
step_channel(2);
#undef step_channel
- // ... the noise generator. This recomputes the new bit repeatedly but harmlessly, only shifting
+ // Update the noise generator. This recomputes the new bit repeatedly but harmlessly, only shifting
// it into the official 17 upon divider underflow.
if(noise_counter_) noise_counter_--;
else {
- noise_counter_ = noise_period_;
+ noise_counter_ = noise_period_ << 1; // To cover the double resolution of envelopes.
noise_output_ ^= noise_shift_register_&1;
noise_shift_register_ |= ((noise_shift_register_ ^ (noise_shift_register_ >> 3))&1) << 17;
noise_shift_register_ >>= 1;
}
- // ... and the envelope generator. Table based for pattern lookup, with a 'refill' step: a way of
- // implementing non-repeating patterns by locking them to table position 0x1f.
+ // Update the envelope generator. Table based for pattern lookup, with a 'refill' step: a way of
+ // implementing non-repeating patterns by locking them to the final table position.
if(envelope_divider_) envelope_divider_--;
else {
envelope_divider_ = envelope_period_;
envelope_position_ ++;
- if(envelope_position_ == 32) envelope_position_ = envelope_overflow_masks_[output_registers_[13]];
+ if(envelope_position_ == 64) envelope_position_ = envelope_overflow_masks_[output_registers_[13]];
}
evaluate_output_volume();
- for(int ic = 0; ic < 8 && c < number_of_samples; ic++) {
+ for(int ic = 0; ic < 4 && c < number_of_samples; ic++) {
target[c] = output_volume_;
c++;
master_divider_++;
}
}
- master_divider_ &= 7;
+ master_divider_ &= 3;
}
void AY38910::evaluate_output_volume() {
- int envelope_volume = envelope_shapes_[output_registers_[13]][envelope_position_];
+ int envelope_volume = envelope_shapes_[output_registers_[13]][envelope_position_ | envelope_position_mask_];
// The output level for a channel is:
// 1 if neither tone nor noise is enabled;
@@ -142,9 +161,10 @@ void AY38910::evaluate_output_volume() {
};
#undef level
- // Channel volume is a simple selection: if the bit at 0x10 is set, use the envelope volume; otherwise use the lower four bits
+ // Channel volume is a simple selection: if the bit at 0x10 is set, use the envelope volume; otherwise use the lower four bits,
+ // mapped to the range 1–31 in case this is a YM.
#define channel_volume(c) \
- ((output_registers_[c] >> 4)&1) * envelope_volume + (((output_registers_[c] >> 4)&1)^1) * (output_registers_[c]&0xf)
+ ((output_registers_[c] >> 4)&1) * envelope_volume + (((output_registers_[c] >> 4)&1)^1) * (((output_registers_[c]&0xf) << 1) + 1)
const int volumes[3] = {
channel_volume(8),
diff --git a/Components/AY38910/AY38910.hpp b/Components/AY38910/AY38910.hpp
index 1eae0cefe..2a1d777c4 100644
--- a/Components/AY38910/AY38910.hpp
+++ b/Components/AY38910/AY38910.hpp
@@ -116,11 +116,11 @@ class AY38910: public ::Outputs::Speaker::SampleSource {
int envelope_period_ = 0;
int envelope_divider_ = 0;
- int envelope_position_ = 0;
- int envelope_shapes_[16][32];
+ int envelope_position_ = 0, envelope_position_mask_ = 0;
+ int envelope_shapes_[16][64];
int envelope_overflow_masks_[16];
- int volumes_[16];
+ int volumes_[32];
enum ControlState {
Inactive,