Added DAC to ym2612 and changed mixing method

emulator/core/src/error.rs

@@ -57,7 +57,7 @@ pub enum LogLevel {
     Debug,
 }
 
-static mut LOG_LEVEL: LogLevel = LogLevel::Info;
+static mut LOG_LEVEL: LogLevel = LogLevel::Warning;
 
 pub fn log_level() -> LogLevel {
     unsafe { LOG_LEVEL }

emulator/frontends/common/src/audio.rs

@@ -58,7 +58,7 @@ impl AudioSource {
             self.sequence_num = mixer_sequence_num;
 
             for i in 0..locked_mixer.buffer.len() {
-                locked_mixer.buffer[i] += self.buffer.next().unwrap_or(0.0);
+                locked_mixer.buffer[i] = (locked_mixer.buffer[i] + self.buffer.next().unwrap_or(0.0)).clamp(-1.0, 1.0);
             }
 
             self.frame_size = locked_mixer.frame_size();

emulator/peripherals/yamaha/src/sn76489.rs

@@ -40,7 +40,7 @@ impl ToneGenerator {
     }
 
     pub fn get_sample(&mut self) -> f32 {
-        self.wave.next().unwrap() / self.attenuation
+        self.wave.next().unwrap() / (self.attenuation + 1.0)
     }
 }
 
@@ -115,23 +115,18 @@ impl Steppable for Sn76489 {
             let mut buffer = vec![0.0; samples];
             for i in 0..samples {
                 let mut sample = 0.0;
-                let mut count = 0;
 
                 for ch in 0..3 {
                     if self.tones[ch].on {
                         sample += self.tones[ch].get_sample();
-                        count += 1;
                     }
                 }
 
                 if self.noise.on {
                     sample += self.noise.get_sample();
-                    count += 1;
                 }
 
-                if count > 0 {
-                    buffer[i] = sample / count as f32;
-                }
+                buffer[i] = sample.clamp(-1.0, 1.0);
             }
             self.source.write_samples(&buffer);
         } else {

emulator/peripherals/yamaha/src/ym2612.rs

@@ -1,5 +1,6 @@
 
 use std::num::NonZeroU8;
+use std::collections::VecDeque;
 
 use moa_core::{debug, warning};
 use moa_core::{System, Error, ClockElapsed, Address, Addressable, Steppable, Transmutable};
@@ -154,6 +155,9 @@ pub struct Ym2612 {
 
     pub channels: Vec<Channel>,
     pub channel_frequencies: [(u8, u16); CHANNELS],
+
+    pub dac_enabled: bool,
+    pub dac: VecDeque<u8>,
 }
 
 impl Ym2612 {
@@ -166,6 +170,8 @@ impl Ym2612 {
             selected_reg_1: None,
             channels: vec![Channel::new(sample_rate); 8],
             channel_frequencies: [(0, 0); CHANNELS],
+            dac_enabled: false,
+            dac: VecDeque::with_capacity(100),
         })
     }
 
@@ -175,6 +181,14 @@ impl Ym2612 {
             self.channels[ch].on = data >> 4;
             self.channels[ch].reset();
             println!("Note: {}: {:x}", ch, self.channels[ch].on);
+        } else if reg == 0x2a {
+            if self.dac_enabled {
+                for _ in 0..3 {
+                    self.dac.push_back(data);
+                }
+            }
+        } else if reg == 0x2b {
+            self.dac_enabled = data & 0x80 != 0;
         } else if (reg & 0xF0) == 0x30 {
             let (ch, op) = get_ch_op(bank, reg);
             let multiplier = if data == 0 { 0.5 } else { (data & 0x0F) as f32 };
@@ -249,18 +263,22 @@ impl Steppable for Ym2612 {
             let mut buffer = vec![0.0; samples];
             for i in 0..samples {
                 let mut sample = 0.0;
-                let mut count = 0;
 
-                for ch in 0..7 {
+                for ch in 0..6 {
                     if self.channels[ch].on != 0 {
                         sample += self.channels[ch].get_sample();
-                        count += 1;
                     }
                 }
 
-                if count > 0 {
-                    buffer[i] = sample / count as f32;
+                if self.dac_enabled {
+                    if let Some(data) = self.dac.pop_front() {
+                        sample += data as f32 / 255.0;
+                    }
+                } else if self.channels[6].on != 0 {
+                    sample += self.channels[6].get_sample();
                 }
+
+                buffer[i] = sample.clamp(-1.0, 1.0);
             }
             self.source.write_samples(&buffer);
         //}

emulator/systems/genesis/src/system.rs

@@ -70,7 +70,7 @@ pub fn build_genesis<H: Host>(host: &mut H, mut options: SegaGenesisOptions) ->
     // Build the Coprocessor's Bus
     let bank_register = Signal::new(0);
     let coproc_ram = wrap_transmutable(MemoryBlock::new(vec![0; 0x00002000]));
-    let coproc_ym_sound = wrap_transmutable(AddressRepeater::new(wrap_transmutable(Ym2612::create(host)?), 0x2000));
+    let coproc_ym_sound = wrap_transmutable(Ym2612::create(host)?);
     let coproc_sn_sound = wrap_transmutable(Sn76489::create(host)?);
     let coproc_register = wrap_transmutable(CoprocessorBankRegister::new(bank_register.clone()));
     let coproc_area = wrap_transmutable(CoprocessorBankArea::new(bank_register, system.bus.clone()));

todo.txt

@@ -1,4 +1,8 @@
 
+* test the Z80 more, add tests
+* double check the functioning of the banked areas and register settings for Z80 coprocessor
+* address repeater on ym2612 doesn't seem to work the same, when it's on the 68000 device.  The Z80 device doesn't have an affect, but maybe it's not being used
+
 * make the keys easier to config...
 
 * add log crate to core
@@ -17,6 +21,7 @@ Web Assembly:
 
 
 * fix audio, and/or make it possible to disable audio processing/simulation for one or both sound chips (might be nice to have sn76489 but not ym2612)
+* should you have a separate attenuation value for each input in the mixer so that you can make one chip quieter (the sn76489 is pretty loud, and I added a fixed offset to the attenuation for now)
 
 
 Harte Tests: