From 278953ab78a6a19bf72f6ff0a11f88e6c3f446b6 Mon Sep 17 00:00:00 2001
From: Rekai Musuka <rekai@musuka.dev>
Date: Thu, 24 Jun 2021 01:12:55 -0500
Subject: [PATCH] chore(snd): implement shift amount for channel 3 volume

---
 src/bus.rs   |  4 ++--
 src/sound.rs | 15 ++++++++++++++-
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/bus.rs b/src/bus.rs
index da630bf..c1255e4 100644
--- a/src/bus.rs
+++ b/src/bus.rs
@@ -238,7 +238,7 @@ impl BusIo for Bus {
                     0x24 => self.snd.ctrl.channel.into(),
                     0x25 => self.snd.ctrl.output.into(),
                     0x26 => self.snd.ctrl.status.into(),
-                    0x30..=0x3F => self.snd.ch3.ram[addr as usize - 0xFF30],
+                    0x30..=0x3F => self.snd.ch3.wave_ram[addr as usize - 0xFF30],
                     0x40 => self.ppu.ctrl.into(),
                     0x41 => self.ppu.stat.into(),
                     0x42 => self.ppu.pos.scroll_y,
@@ -355,7 +355,7 @@ impl BusIo for Bus {
                     0x24 => self.snd.ctrl.channel = byte.into(),
                     0x25 => self.snd.ctrl.output = byte.into(),
                     0x26 => self.snd.ctrl.status = byte.into(), // FIXME: Should we control which bytes are written to here?
-                    0x30..=0x3F => self.snd.ch3.ram[addr as usize - 0xFF30] = byte,
+                    0x30..=0x3F => self.snd.ch3.wave_ram[addr as usize - 0xFF30] = byte,
                     0x40 => self.ppu.ctrl = byte.into(),
                     0x41 => self.ppu.stat.update(byte),
                     0x42 => self.ppu.pos.scroll_y = byte,
diff --git a/src/sound.rs b/src/sound.rs
index f4545f8..f85a143 100644
--- a/src/sound.rs
+++ b/src/sound.rs
@@ -645,7 +645,7 @@ pub(crate) struct Channel3 {
     pub(crate) freq_lo: u8,
     /// 0xFF1E | NR34 - Channel 3 Frequency high
     freq_hi: FrequencyHigh,
-    pub(crate) ram: [u8; WAVE_PATTERN_RAM_LEN],
+    pub(crate) wave_ram: [u8; WAVE_PATTERN_RAM_LEN],
 
     // Length Functionality
     length_timer: u16,
@@ -713,6 +713,19 @@ enum Channel3Volume {
     Quarter = 3,
 }
 
+impl Channel3Volume {
+    pub fn shift_count(&self) -> u8 {
+        use Channel3Volume::*;
+
+        match *self {
+            Mute => 4,
+            Full => 0,
+            Half => 1,
+            Quarter => 2,
+        }
+    }
+}
+
 impl Default for Channel3Volume {
     fn default() -> Self {
         Self::Mute