2026-05-15 15:14:24

Author: mohanson

src/apu.rs

@@ -255,44 +255,41 @@ impl Swp {
         self.e = p != 0 || r.swp_sh() != 0;
         self.n = false;
         if r.swp_sh() != 0 {
-            let (_, ov) = self.calc(r);
-            return ov;
+            return self.calc(r) >= 2048;
         }
         false
     }
 
-    fn calc(&mut self, r: &Reg) -> (u16, bool) {
+    fn calc(&mut self, r: &Reg) -> u16 {
         let d = self.s >> r.swp_sh();
-        let f = if r.swp_neg() {
+        if r.swp_neg() {
             self.n = true;
             self.s.wrapping_sub(d)
         } else {
             self.s.wrapping_add(d)
-        };
-        (f, f >= 2048)
+        }
     }
 
-    fn clock(&mut self, r: &mut Reg) -> bool {
+    fn step(&mut self, r: &mut Reg) -> bool {
         let fired = self.t.step(1) != 0;
         if fired {
-            // Reload period from the current register on every fire so writes to
-            // NR10 between fires take effect immediately. Period 0 → 8.
+            // Reload period from the current register on every fire so writes to NR10 between fires take effect
+            // immediately. Period 0 -> 8.
             let p = r.swp_p();
             self.t.p = if p == 0 { 8 } else { u32::from(p) };
             self.t.n = 0;
         }
         if !fired || !self.e || r.swp_p() == 0 {
             return false;
         }
-        let (f, ov) = self.calc(r);
-        if ov {
+        let f = self.calc(r);
+        if f >= 2048 {
             return true;
         }
-        if f < 2048 && r.swp_sh() != 0 {
+        if r.swp_sh() != 0 {
             self.s = f;
             r.freq_update(f);
-            let (_, ov2) = self.calc(r);
-            if ov2 {
+            if self.calc(r) >= 2048 {
                 return true;
             }
         }
@@ -1198,7 +1195,7 @@ impl Ticker for Apu {
                 }
             }
             if Fseq::swp(s) && self.ch1.on {
-                if self.ch1.swp.clock(&mut self.ch1.r) {
+                if self.ch1.swp.step(&mut self.ch1.r) {
                     self.ch1.on = false;
                 }
                 self.ch1.tmr.p = self.ch1.r.per_sq();