From 1f23a1b86c8dd233ec532a06045fe108caf0cd43 Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Sun, 7 Jun 2020 15:12:34 +0800
Subject: [PATCH] enable FPU on Core1

---
 src/runtime/src/kernel.rs | 13 +++++++++++++
 src/runtime/src/main.rs   |  1 +
 2 files changed, 14 insertions(+)

diff --git a/src/runtime/src/kernel.rs b/src/runtime/src/kernel.rs
index eb5aa9e..4ff27d4 100644
--- a/src/runtime/src/kernel.rs
+++ b/src/runtime/src/kernel.rs
@@ -128,6 +128,19 @@ fn resolve(required: &[u8]) -> Option<u32> {
 pub fn main_core1() {
     debug!("Core1 started");
 
+    unsafe {
+        llvm_asm!("
+            mrc p15, 0, r1, c1, c0, 2
+            orr r1, r1, (0b1111<<20)
+            mcr p15, 0, r1, c1, c0, 2
+
+            vmrs r1, fpexc
+            orr r1, r1, (1<<30)
+            vmsr fpexc, r1
+            ":::"r1");
+    }
+    debug!("FPU enabled on Core1");
+
     let mut core1_tx = None;
     while core1_tx.is_none() {
         core1_tx = CHANNEL_1TO0.lock().take();
diff --git a/src/runtime/src/main.rs b/src/runtime/src/main.rs
index 8d62a75..48522df 100644
--- a/src/runtime/src/main.rs
+++ b/src/runtime/src/main.rs
@@ -1,6 +1,7 @@
 #![no_std]
 #![no_main]
 #![recursion_limit="1024"]  // for futures_util::select!
+#![feature(llvm_asm)]
 
 extern crate alloc;