The negation steps in FCADD must honour FPCR.AH's "don't change the
sign of a NaN" semantics. Implement this by encoding FPCR.AH into
the SIMD data field passed to the helper and using that to decide
whether to negate the values.
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
---
target/arm/tcg/translate-a64.c | 10 +++++++--
target/arm/tcg/vec_helper.c | 39 ++++++++++++++++++++++++++++------
2 files changed, 41 insertions(+), 8 deletions(-)
diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index ce9ab75bc2f..0827dff16b2 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -6117,8 +6117,14 @@ static gen_helper_gvec_3_ptr * const f_vector_fcadd[3] =
{
gen_helper_gvec_fcadds,
gen_helper_gvec_fcaddd,
};
-TRANS_FEAT(FCADD_90, aa64_fcma, do_fp3_vector, a, 0, f_vector_fcadd)
-TRANS_FEAT(FCADD_270, aa64_fcma, do_fp3_vector, a, 1, f_vector_fcadd)
+/*
+ * Encode FPCR.AH into the data so the helper knows whether the
+ * negations it does should avoid flipping the sign bit on a NaN
+ */
+TRANS_FEAT(FCADD_90, aa64_fcma, do_fp3_vector, a, 0 | (s->fpcr_ah << 1),
+ f_vector_fcadd)
+TRANS_FEAT(FCADD_270, aa64_fcma, do_fp3_vector, a, 1 | (s->fpcr_ah << 1),
+ f_vector_fcadd)
static bool trans_FCMLA_v(DisasContext *s, arg_FCMLA_v *a)
{
diff --git a/target/arm/tcg/vec_helper.c b/target/arm/tcg/vec_helper.c
index 3b87e5b8d6d..382b5da4a9c 100644
--- a/target/arm/tcg/vec_helper.c
+++ b/target/arm/tcg/vec_helper.c
@@ -881,6 +881,7 @@ void HELPER(gvec_fcaddh)(void *vd, void *vn, void *vm,
float16 *m = vm;
uint32_t neg_real = extract32(desc, SIMD_DATA_SHIFT, 1);
uint32_t neg_imag = neg_real ^ 1;
+ bool fpcr_ah = extract64(desc, SIMD_DATA_SHIFT + 1, 1);
uintptr_t i;
/* Shift boolean to the sign bit so we can xor to negate. */
@@ -889,9 +890,17 @@ void HELPER(gvec_fcaddh)(void *vd, void *vn, void *vm,
for (i = 0; i < opr_sz / 2; i += 2) {
float16 e0 = n[H2(i)];
- float16 e1 = m[H2(i + 1)] ^ neg_imag;
+ float16 e1 = m[H2(i + 1)];
float16 e2 = n[H2(i + 1)];
- float16 e3 = m[H2(i)] ^ neg_real;
+ float16 e3 = m[H2(i)];
+
+ /* FPNeg() mustn't flip sign of a NaN if FPCR.AH == 1 */
+ if (!(fpcr_ah && float16_is_any_nan(e1))) {
+ e1 ^= neg_imag;
+ }
+ if (!(fpcr_ah && float16_is_any_nan(e3))) {
+ e3 ^= neg_real;
+ }
d[H2(i)] = float16_add(e0, e1, fpst);
d[H2(i + 1)] = float16_add(e2, e3, fpst);
@@ -908,6 +917,7 @@ void HELPER(gvec_fcadds)(void *vd, void *vn, void *vm,
float32 *m = vm;
uint32_t neg_real = extract32(desc, SIMD_DATA_SHIFT, 1);
uint32_t neg_imag = neg_real ^ 1;
+ bool fpcr_ah = extract64(desc, SIMD_DATA_SHIFT + 1, 1);
uintptr_t i;
/* Shift boolean to the sign bit so we can xor to negate. */
@@ -916,9 +926,17 @@ void HELPER(gvec_fcadds)(void *vd, void *vn, void *vm,
for (i = 0; i < opr_sz / 4; i += 2) {
float32 e0 = n[H4(i)];
- float32 e1 = m[H4(i + 1)] ^ neg_imag;
+ float32 e1 = m[H4(i + 1)];
float32 e2 = n[H4(i + 1)];
- float32 e3 = m[H4(i)] ^ neg_real;
+ float32 e3 = m[H4(i)];
+
+ /* FPNeg() mustn't flip sign of a NaN if FPCR.AH == 1 */
+ if (!(fpcr_ah && float32_is_any_nan(e1))) {
+ e1 ^= neg_imag;
+ }
+ if (!(fpcr_ah && float32_is_any_nan(e3))) {
+ e3 ^= neg_real;
+ }
d[H4(i)] = float32_add(e0, e1, fpst);
d[H4(i + 1)] = float32_add(e2, e3, fpst);
@@ -935,6 +953,7 @@ void HELPER(gvec_fcaddd)(void *vd, void *vn, void *vm,
float64 *m = vm;
uint64_t neg_real = extract64(desc, SIMD_DATA_SHIFT, 1);
uint64_t neg_imag = neg_real ^ 1;
+ bool fpcr_ah = extract64(desc, SIMD_DATA_SHIFT + 1, 1);
uintptr_t i;
/* Shift boolean to the sign bit so we can xor to negate. */
@@ -943,9 +962,17 @@ void HELPER(gvec_fcaddd)(void *vd, void *vn, void *vm,
for (i = 0; i < opr_sz / 8; i += 2) {
float64 e0 = n[i];
- float64 e1 = m[i + 1] ^ neg_imag;
+ float64 e1 = m[i + 1];
float64 e2 = n[i + 1];
- float64 e3 = m[i] ^ neg_real;
+ float64 e3 = m[i];
+
+ /* FPNeg() mustn't flip sign of a NaN if FPCR.AH == 1 */
+ if (!(fpcr_ah && float64_is_any_nan(e1))) {
+ e1 ^= neg_imag;
+ }
+ if (!(fpcr_ah && float64_is_any_nan(e3))) {
+ e3 ^= neg_real;
+ }
d[i] = float64_add(e0, e1, fpst);
d[i + 1] = float64_add(e2, e3, fpst);
--
2.34.1
