From ccec9d7fed72a262912a12097969b14980d1b5ed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Robert=20J=C3=B6rdens?= <rj@quartiq.de>
Date: Fri, 19 Feb 2021 09:29:38 +0100
Subject: [PATCH] complex: rename extension trait, fix MulScaled

---
 dsp/src/complex.rs         | 39 ++++++++++++++------------------------
 dsp/src/lockin.rs          |  2 +-
 src/bin/lockin-external.rs |  2 +-
 src/bin/lockin-internal.rs |  2 +-
 4 files changed, 17 insertions(+), 28 deletions(-)

diff --git a/dsp/src/complex.rs b/dsp/src/complex.rs
index 42d736b..3349460 100644
--- a/dsp/src/complex.rs
+++ b/dsp/src/complex.rs
@@ -2,33 +2,21 @@ pub use num::Complex;
 
 use super::{atan2, cossin};
 
-pub trait Map<F> {
-    fn map(&self, func: F) -> Self;
-}
-
-impl<F: Fn(T) -> T, T: Copy> Map<F> for Complex<T> {
-    fn map(&self, func: F) -> Self {
-        Complex {
-            re: func(self.re),
-            im: func(self.im),
-        }
-    }
-}
-
-pub trait FastInt<T, U> {
+/// Complex extension trait offering DSP (fast, good accuracy) functionality.
+pub trait ComplexExt<T, U> {
     fn from_angle(angle: T) -> Self;
     fn abs_sqr(&self) -> U;
     fn log2(&self) -> T;
     fn arg(&self) -> T;
 }
 
-impl FastInt<i32, u32> for Complex<i32> {
+impl ComplexExt<i32, u32> for Complex<i32> {
     /// Return a Complex on the unit circle given an angle.
     ///
     /// Example:
     ///
     /// ```
-    /// use dsp::{Complex, FastInt};
+    /// use dsp::{Complex, ComplexExt};
     /// Complex::<i32>::from_angle(0);
     /// Complex::<i32>::from_angle(1 << 30);  // pi/2
     /// Complex::<i32>::from_angle(-1 << 30);  // -pi/2
@@ -47,7 +35,7 @@ impl FastInt<i32, u32> for Complex<i32> {
     /// Example:
     ///
     /// ```
-    /// use dsp::{Complex, FastInt};
+    /// use dsp::{Complex, ComplexExt};
     /// assert_eq!(Complex::new(i32::MIN, 0).abs_sqr(), 1 << 31);
     /// assert_eq!(Complex::new(i32::MAX, i32::MAX).abs_sqr(), u32::MAX - 3);
     /// ```
@@ -67,7 +55,7 @@ impl FastInt<i32, u32> for Complex<i32> {
     /// Example:
     ///
     /// ```
-    /// use dsp::{Complex, FastInt};
+    /// use dsp::{Complex, ComplexExt};
     /// assert_eq!(Complex::new(i32::MAX, i32::MAX).log2(), -1);
     /// assert_eq!(Complex::new(i32::MAX, 0).log2(), -2);
     /// assert_eq!(Complex::new(1, 0).log2(), -63);
@@ -86,7 +74,7 @@ impl FastInt<i32, u32> for Complex<i32> {
     /// Example:
     ///
     /// ```
-    /// use dsp::{Complex, FastInt};
+    /// use dsp::{Complex, ComplexExt};
     /// assert_eq!(Complex::new(1, 0).arg(), 0);
     /// assert_eq!(Complex::new(-i32::MAX, 1).arg(), i32::MAX);
     /// assert_eq!(Complex::new(-i32::MAX, -1).arg(), -i32::MAX);
@@ -99,6 +87,7 @@ impl FastInt<i32, u32> for Complex<i32> {
     }
 }
 
+/// Full scale fixed point multiplication.
 pub trait MulScaled<T> {
     fn mul_scaled(self, other: T) -> Self;
 }
@@ -110,8 +99,8 @@ impl MulScaled<Complex<i32>> for Complex<i32> {
         let c = other.re as i64;
         let d = other.im as i64;
         Complex {
-            re: ((a * c - b * d + (1 << 31)) >> 32) as i32,
-            im: ((b * c + a * d + (1 << 31)) >> 32) as i32,
+            re: ((a * c - b * d + (1 << 30)) >> 31) as i32,
+            im: ((b * c + a * d + (1 << 30)) >> 31) as i32,
         }
     }
 }
@@ -119,8 +108,8 @@ impl MulScaled<Complex<i32>> for Complex<i32> {
 impl MulScaled<i32> for Complex<i32> {
     fn mul_scaled(self, other: i32) -> Self {
         Complex {
-            re: ((other as i64 * self.re as i64 + (1 << 31)) >> 32) as i32,
-            im: ((other as i64 * self.im as i64 + (1 << 31)) >> 32) as i32,
+            re: ((other as i64 * self.re as i64 + (1 << 30)) >> 31) as i32,
+            im: ((other as i64 * self.im as i64 + (1 << 30)) >> 31) as i32,
         }
     }
 }
@@ -128,8 +117,8 @@ impl MulScaled<i32> for Complex<i32> {
 impl MulScaled<i16> for Complex<i32> {
     fn mul_scaled(self, other: i16) -> Self {
         Complex {
-            re: (other as i32 * (self.re >> 16) + (1 << 15)) >> 16,
-            im: (other as i32 * (self.im >> 16) + (1 << 15)) >> 16,
+            re: (other as i32 * (self.re >> 16) + (1 << 14)) >> 15,
+            im: (other as i32 * (self.im >> 16) + (1 << 14)) >> 15,
         }
     }
 }
diff --git a/dsp/src/lockin.rs b/dsp/src/lockin.rs
index f0a2767..6a977b4 100644
--- a/dsp/src/lockin.rs
+++ b/dsp/src/lockin.rs
@@ -1,4 +1,4 @@
-use super::{Complex, FastInt, Lowpass, MulScaled};
+use super::{Complex, ComplexExt, Lowpass, MulScaled};
 use generic_array::typenum::U2;
 
 #[derive(Clone, Default)]
diff --git a/src/bin/lockin-external.rs b/src/bin/lockin-external.rs
index b40037f..3d7ff0b 100644
--- a/src/bin/lockin-external.rs
+++ b/src/bin/lockin-external.rs
@@ -6,7 +6,7 @@ use stm32h7xx_hal as hal;
 
 use stabilizer::{hardware, hardware::design_parameters};
 
-use dsp::{Accu, Complex, FastInt, Lockin, RPLL};
+use dsp::{Accu, Complex, ComplexExt, Lockin, RPLL};
 use hardware::{
     Adc0Input, Adc1Input, Dac0Output, Dac1Output, InputStamper, AFE0, AFE1,
 };
diff --git a/src/bin/lockin-internal.rs b/src/bin/lockin-internal.rs
index 3539993..1f9df6e 100644
--- a/src/bin/lockin-internal.rs
+++ b/src/bin/lockin-internal.rs
@@ -2,7 +2,7 @@
 #![no_std]
 #![no_main]
 
-use dsp::{Accu, Complex, FastInt, Lockin};
+use dsp::{Accu, Complex, ComplexExt, Lockin};
 use hardware::{Adc1Input, Dac0Output, Dac1Output, AFE0, AFE1};
 use stabilizer::{hardware, hardware::design_parameters};