target/arm: Fix fp_status_f16 tininess before rounding

In commit d81ce0ef we added an extra float_status field
fp_status_fp16 for Arm, but forgot to initialize it correctly
by setting it to float_tininess_before_rounding. This currently
will only cause problems for the new V8_FP16 feature, since the
float-to-float conversion code doesn't use it yet. The effect
would be that we failed to set the Underflow IEEE exception flag
in all the cases where we should.

Add the missing initialization.

Fixes: d81ce0ef
Cc: qemu-stable@nongnu.org
Reviewed-by: NRichard Henderson <richard.henderson@linaro.org>
Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Message-id: 20180512004311.9299-16-richard.henderson@linaro.org

target/arm/cpu.c

@@ -324,6 +324,8 @@ static void arm_cpu_reset(CPUState *s)
                               &env->vfp.fp_status);
     set_float_detect_tininess(float_tininess_before_rounding,
                               &env->vfp.standard_fp_status);
+    set_float_detect_tininess(float_tininess_before_rounding,
+                              &env->vfp.fp_status_f16);
 #ifndef CONFIG_USER_ONLY
     if (kvm_enabled()) {
         kvm_arm_reset_vcpu(cpu);