Fixed FPU support.

Selecting proper FPU flags in build_rules and enabling FPU during startup.

1 files changed, 6 insertions, 0 deletions

diff --git a/startup/entry.cpp b/startup/entry.cpp
index d7385f8..64aac37 100644
--- a/startup/entry.cpp
+++ b/startup/entry.cpp
@@ -1,5 +1,6 @@
 #include <stdint.h>
 #include <rcc/rcc.h>
+#include <cortex_m/fpu.h>
 
 int main();
 
@@ -35,6 +36,11 @@ void __attribute__((naked)) entry() {
 		*wp++ = 0;
 	}
 	
+	// Enable FPU before calling any functions that can invoke FPU instructions.
+	#ifdef HAS_FPU
+	COPROC.CPAC |= (3 << 22) | (3 << 20);
+	#endif
+	
 	// Call constructors.
 	funcp_t* fp = &_init_array_start;