Add CORDIC Support (#132)

* add CORDIC support

* should fix CI failure

* add example

* require defmt for cordic example

* put cordic stuff behind feature gate

this will fail CI pending fix

* significant refactor and dynamic mode

* remove some erroneous whitespace, O -> OFFSET, more inline const exprs

* simplify type signature, distinguish state vs feature

Cargo.toml

@@ -19,6 +19,7 @@ bitflags = "1.2"
 vcell = "0.1"
 static_assertions = "1.1"
 fugit = "0.3.5"
+fixed = { version = "1.28.0", optional = true }
 
 [dependencies.cortex-m]
 version = "0.7.7"
@@ -89,6 +90,7 @@ log-itm = ["cortex-m-log/itm"]
 log-rtt = []
 log-semihost = ["cortex-m-log/semihosting"]
 defmt-logging = ["defmt"]
+cordic = ["dep:fixed"]
 
 [profile.dev]
 codegen-units = 1
@@ -105,3 +107,7 @@ lto = true
 [[example]]
 name = "flash_with_rtic"
 required-features = ["stm32g474"]
+
+[[example]]
+name = "cordic"
+required-features = ["cordic"]

examples/cordic.rs

@@ -0,0 +1,57 @@
+#![deny(warnings)]
+#![deny(unsafe_code)]
+#![no_main]
+#![no_std]
+
+extern crate cortex_m;
+extern crate cortex_m_rt as rt;
+extern crate stm32g4xx_hal as hal;
+
+use fixed::types::I1F15;
+use hal::cordic::{
+    func::{dynamic::Mode as _, scale::N0, Magnitude, SinCos, Sqrt},
+    prec::P60,
+    types::{Q15, Q31},
+    Ext as _,
+};
+use hal::prelude::*;
+use hal::pwr::PwrExt;
+use hal::rcc::Config;
+use hal::stm32;
+use rt::entry;
+
+#[macro_use]
+mod utils;
+
+use utils::logger::println;
+
+#[entry]
+fn main() -> ! {
+    let dp = stm32::Peripherals::take().expect("cannot take peripherals");
+    let pwr = dp.PWR.constrain().freeze();
+    let mut rcc = dp.RCC.freeze(Config::hsi(), pwr);
+
+    let mut cordic = dp
+        .CORDIC
+        .constrain(&mut rcc)
+        .freeze::<Q15, Q31, SinCos, P60>(); // 16 bit arguments, 32 bit results, compute sine and cosine, 60 iterations
+
+    // static operation (zero overhead)
+
+    cordic.start(I1F15::from_num(-0.25 /* -45 degreees */));
+
+    let (sin, cos) = cordic.result();
+
+    println!("sin: {}, cos: {}", sin.to_num::<f32>(), cos.to_num::<f32>());
+
+    // dynamic operation
+
+    let mut cordic = cordic.into_dynamic();
+
+    let sqrt = cordic.run::<Sqrt<N0>>(I1F15::from_num(0.25));
+    println!("sqrt: {}", sqrt.to_num::<f32>());
+    let magnitude = cordic.run::<Magnitude>((I1F15::from_num(0.25), I1F15::from_num(0.5)));
+    println!("magnitude: {}", magnitude.to_num::<f32>());
+
+    loop {}
+}