[PATCH 54/76] target/arm: Handle FPCR.AH in vector FABD

[Peter Maydell]

Split the handling of vector FABD so that it calls a different set
of helpers when FPCR.AH is 1, which implement the "no negation of
the sign of a NaN" semantics.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/helper.h            |  4 ++++
 target/arm/tcg/translate-a64.c |  7 ++++++-
 target/arm/tcg/vec_helper.c    | 23 +++++++++++++++++++++++
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/target/arm/helper.h b/target/arm/helper.h
index 15bad0773c0..43505d5fedc 100644
--- a/target/arm/helper.h
+++ b/target/arm/helper.h
@@ -722,6 +722,10 @@ DEF_HELPER_FLAGS_5(gvec_fabd_h, TCG_CALL_NO_RWG, void, 
ptr, ptr, ptr, fpst, i32)
 DEF_HELPER_FLAGS_5(gvec_fabd_s, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, fpst, 
i32)
 DEF_HELPER_FLAGS_5(gvec_fabd_d, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, fpst, 
i32)
 
+DEF_HELPER_FLAGS_5(gvec_ah_fabd_h, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, fpst, 
i32)
+DEF_HELPER_FLAGS_5(gvec_ah_fabd_s, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, fpst, 
i32)
+DEF_HELPER_FLAGS_5(gvec_ah_fabd_d, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, fpst, 
i32)
+
 DEF_HELPER_FLAGS_5(gvec_fceq_h, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, fpst, 
i32)
 DEF_HELPER_FLAGS_5(gvec_fceq_s, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, fpst, 
i32)
 DEF_HELPER_FLAGS_5(gvec_fceq_d, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, fpst, 
i32)
diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index 542e774790b..ce9ab75bc2f 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -5899,7 +5899,12 @@ static gen_helper_gvec_3_ptr * const f_vector_fabd[3] = {
     gen_helper_gvec_fabd_s,
     gen_helper_gvec_fabd_d,
 };
-TRANS(FABD_v, do_fp3_vector, a, 0, f_vector_fabd)
+static gen_helper_gvec_3_ptr * const f_vector_ah_fabd[3] = {
+    gen_helper_gvec_ah_fabd_h,
+    gen_helper_gvec_ah_fabd_s,
+    gen_helper_gvec_ah_fabd_d,
+};
+TRANS(FABD_v, do_fp3_vector_2fn, a, 0, f_vector_fabd, f_vector_ah_fabd)
 
 static gen_helper_gvec_3_ptr * const f_vector_frecps[3] = {
     gen_helper_gvec_recps_h,
diff --git a/target/arm/tcg/vec_helper.c b/target/arm/tcg/vec_helper.c
index d3f2eaa807e..3b87e5b8d6d 100644
--- a/target/arm/tcg/vec_helper.c
+++ b/target/arm/tcg/vec_helper.c
@@ -1302,6 +1302,25 @@ static float64 float64_abd(float64 op1, float64 op2, 
float_status *stat)
     return float64_abs(float64_sub(op1, op2, stat));
 }
 
+/* ABD when FPCR.AH = 1: avoid flipping sign bit of a NaN result */
+static float16 float16_ah_abd(float16 op1, float16 op2, float_status *stat)
+{
+    float16 r = float16_sub(op1, op2, stat);
+    return float16_is_any_nan(r) ? r : float16_abs(r);
+}
+
+static float32 float32_ah_abd(float32 op1, float32 op2, float_status *stat)
+{
+    float32 r = float32_sub(op1, op2, stat);
+    return float32_is_any_nan(r) ? r : float32_abs(r);
+}
+
+static float64 float64_ah_abd(float64 op1, float64 op2, float_status *stat)
+{
+    float64 r = float64_sub(op1, op2, stat);
+    return float64_is_any_nan(r) ? r : float64_abs(r);
+}
+
 /*
  * Reciprocal step. These are the AArch32 version which uses a
  * non-fused multiply-and-subtract.
@@ -1389,6 +1408,10 @@ DO_3OP(gvec_fabd_h, float16_abd, float16)
 DO_3OP(gvec_fabd_s, float32_abd, float32)
 DO_3OP(gvec_fabd_d, float64_abd, float64)
 
+DO_3OP(gvec_ah_fabd_h, float16_ah_abd, float16)
+DO_3OP(gvec_ah_fabd_s, float32_ah_abd, float32)
+DO_3OP(gvec_ah_fabd_d, float64_ah_abd, float64)
+
 DO_3OP(gvec_fceq_h, float16_ceq, float16)
 DO_3OP(gvec_fceq_s, float32_ceq, float32)
 DO_3OP(gvec_fceq_d, float64_ceq, float64)
-- 
2.34.1