iir: vminnm/vmaxnm

Cargo.toml

@@ -62,7 +62,7 @@ branch = "dma"
 [features]
 semihosting = ["panic-semihosting", "cortex-m-log/semihosting"]
 bkpt = [ ]
-nightly = ["cortex-m/inline-asm"]
+nightly = ["cortex-m/inline-asm", "dsp/nightly"]
 
 [profile.dev]
 codegen-units = 1

dsp/Cargo.toml

@@ -6,3 +6,6 @@ edition = "2018"
 
 [dependencies]
 serde = { version = "1.0", features = ["derive"], default-features = false }
+
+[features]
+nightly = []

dsp/src/iir.rs

@@ -24,6 +24,7 @@ fn copysign(x: f32, y: f32) -> f32 {
     }
 }
 
+#[cfg(not(feature = "nightly"))]
 fn max(x: f32, y: f32) -> f32 {
     if x > y {
         x
@@ -32,6 +33,7 @@ fn max(x: f32, y: f32) -> f32 {
     }
 }
 
+#[cfg(not(feature = "nightly"))]
 fn min(x: f32, y: f32) -> f32 {
     if x < y {
         x
@@ -40,6 +42,31 @@ fn min(x: f32, y: f32) -> f32 {
     }
 }
 
+#[cfg(feature = "nightly")]
+fn max(x: f32, y: f32) -> f32 {
+    let o: f32;
+    unsafe {
+        asm!("vmaxnm.f32 {}, {}, {}",
+            lateout(sreg) o, in(sreg) x, in(sreg) y,
+            options(pure, nomem, nostack, preserves_flags)
+        );
+    }
+    o
+}
+
+#[cfg(feature = "nightly")]
+fn min(x: f32, y: f32) -> f32 {
+    let o: f32;
+    unsafe {
+        asm!("vminnm.f32 {}, {}, {}",
+            lateout(sreg) o, in(sreg) x, in(sreg) y,
+            options(pure, nomem, nostack, preserves_flags)
+        );
+    }
+    o
+}
+
+
 // Multiply-accumulate vectors `x` and `a`.
 //
 // A.k.a. dot product.

dsp/src/lib.rs

@@ -1,3 +1,4 @@
 #![no_std]
+#![cfg_attr(feature = "nightly", feature(asm))]
 
 pub mod iir;

src/main.rs

@@ -13,6 +13,9 @@
 fn panic(_info: &core::panic::PanicInfo) -> ! {
     let gpiod = unsafe { &*hal::stm32::GPIOD::ptr() };
     gpiod.odr.modify(|_, w| w.odr6().high().odr12().high()); // FP_LED_1, FP_LED_3
+    #[cfg(feature = "nightly")]
+    core::intrinsics::abort();
+    #[cfg(not(feature = "nightly"))]
     unsafe {
         core::intrinsics::abort();
     }