Enable floating-point coprocessor on reset.

Always enable the floating-point coprocessor with full access on
reset, allowing usage of hard-fp toolchains.

lib/stm32/f4/vector.c

@@ -18,6 +18,8 @@
  * along with this library.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <libopencm3/stm32/f4/scb.h>
+
 #define WEAK __attribute__ ((weak))
 
 /* Symbols exported by the linker script(s): */
@@ -224,6 +226,9 @@ void reset_handler(void)
 
 	__asm__("MSR msp, %0" : : "r"(&_stack));
 
+	/* Enable access to Floating-Point coprocessor. */
+	SCB_CPACR |= SCB_CPACR_FULL * (SCB_CPACR_CP10 | SCB_CPACR_CP11);
+
 	for (src = &_data_loadaddr, dest = &_data; dest < &_edata; src++, dest++)
 		*dest = *src;