arm/translate-a64: add FP16 FRCPX to simd_two_reg_misc_fp16

We go with the localised helper.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20180227143852.11175-25-alex.bennee@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 29 insertions, 0 deletions

diff --git a/target/arm/helper-a64.c b/target/arm/helper-a64.c
index 722fff2349..92a0d55a9c 100644
--- a/target/arm/helper-a64.c
+++ b/target/arm/helper-a64.c
@@ -356,6 +356,35 @@ uint64_t HELPER(neon_addlp_u16)(uint64_t a)
 }
 
 /* Floating-point reciprocal exponent - see FPRecpX in ARM ARM */
+float16 HELPER(frecpx_f16)(float16 a, void *fpstp)
+{
+    float_status *fpst = fpstp;
+    uint16_t val16, sbit;
+    int16_t exp;
+
+    if (float16_is_any_nan(a)) {
+        float16 nan = a;
+        if (float16_is_signaling_nan(a, fpst)) {
+            float_raise(float_flag_invalid, fpst);
+            nan = float16_maybe_silence_nan(a, fpst);
+        }
+        if (fpst->default_nan_mode) {
+            nan = float16_default_nan(fpst);
+        }
+        return nan;
+    }
+
+    val16 = float16_val(a);
+    sbit = 0x8000 & val16;
+    exp = extract32(val16, 10, 5);
+
+    if (exp == 0) {
+        return make_float16(deposit32(sbit, 10, 5, 0x1e));
+    } else {
+        return make_float16(deposit32(sbit, 10, 5, ~exp));
+    }
+}
+
 float32 HELPER(frecpx_f32)(float32 a, void *fpstp)
 {
     float_status *fpst = fpstp;