vfma is available in the vfpv4 fpu and above, the ACLE standard feature
test for double precision hardware fma support is
__ARM_FEATURE_FMA && __ARM_FP&8
we need further checks to work around clang bugs (fixed in clang >=7.0)
&& !__SOFTFP__
because __ARM_FP is defined even with -mfloat-abi=soft
&& !BROKEN_VFP_ASM
to disable the single precision code when inline asm handling is broken.
For runtime selection the HWCAP_ARM_VFPv4 hwcap flag can be used, but
that requires further work.
--- /dev/null
+#include <math.h>
+
+#if __ARM_FEATURE_FMA && __ARM_FP&8 && !__SOFTFP__
+
+double fma(double x, double y, double z)
+{
+ __asm__ ("vfma.f64 %P0, %P1, %P2" : "+w"(z) : "w"(x), "w"(y));
+ return z;
+}
+
+#else
+
+#include "../fma.c"
+
+#endif
--- /dev/null
+#include <math.h>
+
+#if __ARM_FEATURE_FMA && __ARM_FP&4 && !__SOFTFP__ && !BROKEN_VFP_ASM
+
+float fmaf(float x, float y, float z)
+{
+ __asm__ ("vfma.f32 %0, %1, %2" : "+t"(z) : "t"(x), "t"(y));
+ return z;
+}
+
+#else
+
+#include "../fmaf.c"
+
+#endif