diff --git a/dsp/src/iir.rs b/dsp/src/iir.rs
index 5ff0970..dbec8d8 100644
--- a/dsp/src/iir.rs
+++ b/dsp/src/iir.rs
@@ -1,75 +1,8 @@
-use core::ops::{Add, Mul, Neg};
 use serde::{Deserialize, Serialize};
 
-use super::abs;
+use super::{abs, copysign, macc, max, min};
 use core::f32;
 
-// These are implemented here because core::f32 doesn't have them (yet).
-// They are naive and don't handle inf/nan.
-// `compiler-intrinsics`/llvm should have better (robust, universal, and
-// faster) implementations.
-
-fn copysign<T>(x: T, y: T) -> T
-where
-    T: PartialOrd + Default + Neg<Output = T>,
-{
-    if (x >= T::default() && y >= T::default())
-        || (x <= T::default() && y <= T::default())
-    {
-        x
-    } else {
-        -x
-    }
-}
-
-#[cfg(not(feature = "nightly"))]
-fn max<T>(x: T, y: T) -> T
-where
-    T: PartialOrd,
-{
-    if x > y {
-        x
-    } else {
-        y
-    }
-}
-
-#[cfg(not(feature = "nightly"))]
-fn min<T>(x: T, y: T) -> T
-where
-    T: PartialOrd,
-{
-    if x < y {
-        x
-    } else {
-        y
-    }
-}
-
-#[cfg(feature = "nightly")]
-fn max(x: f32, y: f32) -> f32 {
-    core::intrinsics::maxnumf32(x, y)
-}
-
-#[cfg(feature = "nightly")]
-fn min(x: f32, y: f32) -> f32 {
-    core::intrinsics::minnumf32(x, y)
-}
-
-// Multiply-accumulate vectors `x` and `a`.
-//
-// A.k.a. dot product.
-// Rust/LLVM optimize this nicely.
-fn macc<T>(y0: T, x: &[T], a: &[T]) -> T
-where
-    T: Add<Output = T> + Mul<Output = T> + Copy,
-{
-    x.iter()
-        .zip(a)
-        .map(|(x, a)| *x * *a)
-        .fold(y0, |y, xa| y + xa)
-}
-
 /// IIR state and coefficients type.
 ///
 /// To represent the IIR state (input and output memory) during the filter update
diff --git a/dsp/src/lib.rs b/dsp/src/lib.rs
index 90f62f6..67b1882 100644
--- a/dsp/src/lib.rs
+++ b/dsp/src/lib.rs
@@ -1,7 +1,7 @@
 #![cfg_attr(not(test), no_std)]
 #![cfg_attr(feature = "nightly", feature(asm, core_intrinsics))]
 
-use core::ops::Neg;
+use core::ops::{Add, Mul, Neg};
 
 pub type Complex<T> = (T, T);
 
@@ -31,6 +31,72 @@ where
     }
 }
 
+// These are implemented here because core::f32 doesn't have them (yet).
+// They are naive and don't handle inf/nan.
+// `compiler-intrinsics`/llvm should have better (robust, universal, and
+// faster) implementations.
+
+fn copysign<T>(x: T, y: T) -> T
+where
+    T: PartialOrd + Default + Neg<Output = T>,
+{
+    if (x >= T::default() && y >= T::default())
+        || (x <= T::default() && y <= T::default())
+    {
+        x
+    } else {
+        -x
+    }
+}
+
+#[cfg(not(feature = "nightly"))]
+fn max<T>(x: T, y: T) -> T
+where
+    T: PartialOrd,
+{
+    if x > y {
+        x
+    } else {
+        y
+    }
+}
+
+#[cfg(not(feature = "nightly"))]
+fn min<T>(x: T, y: T) -> T
+where
+    T: PartialOrd,
+{
+    if x < y {
+        x
+    } else {
+        y
+    }
+}
+
+#[cfg(feature = "nightly")]
+fn max(x: f32, y: f32) -> f32 {
+    core::intrinsics::maxnumf32(x, y)
+}
+
+#[cfg(feature = "nightly")]
+fn min(x: f32, y: f32) -> f32 {
+    core::intrinsics::minnumf32(x, y)
+}
+
+// Multiply-accumulate vectors `x` and `a`.
+//
+// A.k.a. dot product.
+// Rust/LLVM optimize this nicely.
+fn macc<T>(y0: T, x: &[T], a: &[T]) -> T
+where
+    T: Add<Output = T> + Mul<Output = T> + Copy,
+{
+    x.iter()
+        .zip(a)
+        .map(|(x, a)| *x * *a)
+        .fold(y0, |y, xa| y + xa)
+}
+
 pub mod iir;
 pub mod lockin;
 pub mod pll;