diff mbox series

[69/76] target/arm: Plumb FEAT_RPRES frecpe and frsqrte through to new helper

Message ID 20250124162836.2332150-70-peter.maydell@linaro.org
State New
Headers show
Series target/arm: Implement FEAT_AFP and FEAT_RPRES | expand

Commit Message

Peter Maydell Jan. 24, 2025, 4:28 p.m. UTC
FEAT_RPRES implements an "increased precision" variant of the single
precision FRECPE and FRSQRTE instructions from an 8 bit to a 12
bit mantissa. This applies only when FPCR.AH == 1. Note that the
halfprec and double versions of these insns retain the 8 bit
precision regardless.

In this commit we add all the plumbing to make these instructions
call a new helper function when the increased-precision is in
effect. In the following commit we will provide the actual change
in behaviour in the helpers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/cpu-features.h      |  5 +++++
 target/arm/helper.h            |  4 ++++
 target/arm/tcg/translate-a64.c | 34 ++++++++++++++++++++++++++++++----
 target/arm/tcg/translate-sve.c | 16 ++++++++++++++--
 target/arm/tcg/vec_helper.c    |  2 ++
 target/arm/vfp_helper.c        | 32 ++++++++++++++++++++++++++++++--
 6 files changed, 85 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/target/arm/cpu-features.h b/target/arm/cpu-features.h
index 7bf24c506b3..525e4cee12f 100644
--- a/target/arm/cpu-features.h
+++ b/target/arm/cpu-features.h
@@ -597,6 +597,11 @@  static inline bool isar_feature_aa64_mops(const ARMISARegisters *id)
     return FIELD_EX64(id->id_aa64isar2, ID_AA64ISAR2, MOPS);
 }
 
+static inline bool isar_feature_aa64_rpres(const ARMISARegisters *id)
+{
+    return FIELD_EX64(id->id_aa64isar2, ID_AA64ISAR2, RPRES);
+}
+
 static inline bool isar_feature_aa64_fp_simd(const ARMISARegisters *id)
 {
     /* We always set the AdvSIMD and FP fields identically.  */
diff --git a/target/arm/helper.h b/target/arm/helper.h
index 0a8b4c946e1..dbad1f5d741 100644
--- a/target/arm/helper.h
+++ b/target/arm/helper.h
@@ -245,9 +245,11 @@  DEF_HELPER_4(vfp_muladdh, f16, f16, f16, f16, fpst)
 
 DEF_HELPER_FLAGS_2(recpe_f16, TCG_CALL_NO_RWG, f16, f16, fpst)
 DEF_HELPER_FLAGS_2(recpe_f32, TCG_CALL_NO_RWG, f32, f32, fpst)
+DEF_HELPER_FLAGS_2(recpe_rpres_f32, TCG_CALL_NO_RWG, f32, f32, fpst)
 DEF_HELPER_FLAGS_2(recpe_f64, TCG_CALL_NO_RWG, f64, f64, fpst)
 DEF_HELPER_FLAGS_2(rsqrte_f16, TCG_CALL_NO_RWG, f16, f16, fpst)
 DEF_HELPER_FLAGS_2(rsqrte_f32, TCG_CALL_NO_RWG, f32, f32, fpst)
+DEF_HELPER_FLAGS_2(rsqrte_rpres_f32, TCG_CALL_NO_RWG, f32, f32, fpst)
 DEF_HELPER_FLAGS_2(rsqrte_f64, TCG_CALL_NO_RWG, f64, f64, fpst)
 DEF_HELPER_FLAGS_1(recpe_u32, TCG_CALL_NO_RWG, i32, i32)
 DEF_HELPER_FLAGS_1(rsqrte_u32, TCG_CALL_NO_RWG, i32, i32)
@@ -680,10 +682,12 @@  DEF_HELPER_FLAGS_4(gvec_vrintx_s, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
 
 DEF_HELPER_FLAGS_4(gvec_frecpe_h, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
 DEF_HELPER_FLAGS_4(gvec_frecpe_s, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
+DEF_HELPER_FLAGS_4(gvec_frecpe_rpres_s, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
 DEF_HELPER_FLAGS_4(gvec_frecpe_d, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
 
 DEF_HELPER_FLAGS_4(gvec_frsqrte_h, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
 DEF_HELPER_FLAGS_4(gvec_frsqrte_s, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
+DEF_HELPER_FLAGS_4(gvec_frsqrte_rpres_s, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
 DEF_HELPER_FLAGS_4(gvec_frsqrte_d, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
 
 DEF_HELPER_FLAGS_4(gvec_fcgt0_h, TCG_CALL_NO_RWG, void, ptr, ptr, fpst, i32)
diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index 0b57e35f999..3e2fe46464f 100644
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -8909,7 +8909,14 @@  static const FPScalar1 f_scalar_frecpe = {
     gen_helper_recpe_f32,
     gen_helper_recpe_f64,
 };
-TRANS(FRECPE_s, do_fp1_scalar_ah, a, &f_scalar_frecpe, -1)
+static const FPScalar1 f_scalar_frecpe_rpres = {
+    gen_helper_recpe_f16,
+    gen_helper_recpe_rpres_f32,
+    gen_helper_recpe_f64,
+};
+TRANS(FRECPE_s, do_fp1_scalar_ah, a,
+      s->fpcr_ah && dc_isar_feature(aa64_rpres, s) ?
+      &f_scalar_frecpe_rpres : &f_scalar_frecpe, -1)
 
 static const FPScalar1 f_scalar_frecpx = {
     gen_helper_frecpx_f16,
@@ -8923,7 +8930,14 @@  static const FPScalar1 f_scalar_frsqrte = {
     gen_helper_rsqrte_f32,
     gen_helper_rsqrte_f64,
 };
-TRANS(FRSQRTE_s, do_fp1_scalar_ah, a, &f_scalar_frsqrte, -1)
+static const FPScalar1 f_scalar_frsqrte_rpres = {
+    gen_helper_rsqrte_f16,
+    gen_helper_rsqrte_rpres_f32,
+    gen_helper_rsqrte_f64,
+};
+TRANS(FRSQRTE_s, do_fp1_scalar_ah, a,
+      s->fpcr_ah && dc_isar_feature(aa64_rpres, s) ?
+      &f_scalar_frsqrte_rpres : &f_scalar_frsqrte, -1)
 
 static bool trans_FCVT_s_ds(DisasContext *s, arg_rr *a)
 {
@@ -9954,14 +9968,26 @@  static gen_helper_gvec_2_ptr * const f_frecpe[] = {
     gen_helper_gvec_frecpe_s,
     gen_helper_gvec_frecpe_d,
 };
-TRANS(FRECPE_v, do_gvec_op2_ah_fpst, a->esz, a->q, a->rd, a->rn, 0, f_frecpe)
+static gen_helper_gvec_2_ptr * const f_frecpe_rpres[] = {
+    gen_helper_gvec_frecpe_h,
+    gen_helper_gvec_frecpe_rpres_s,
+    gen_helper_gvec_frecpe_d,
+};
+TRANS(FRECPE_v, do_gvec_op2_ah_fpst, a->esz, a->q, a->rd, a->rn, 0,
+      s->fpcr_ah && dc_isar_feature(aa64_rpres, s) ? f_frecpe_rpres : f_frecpe)
 
 static gen_helper_gvec_2_ptr * const f_frsqrte[] = {
     gen_helper_gvec_frsqrte_h,
     gen_helper_gvec_frsqrte_s,
     gen_helper_gvec_frsqrte_d,
 };
-TRANS(FRSQRTE_v, do_gvec_op2_ah_fpst, a->esz, a->q, a->rd, a->rn, 0, f_frsqrte)
+static gen_helper_gvec_2_ptr * const f_frsqrte_rpres[] = {
+    gen_helper_gvec_frsqrte_h,
+    gen_helper_gvec_frsqrte_rpres_s,
+    gen_helper_gvec_frsqrte_d,
+};
+TRANS(FRSQRTE_v, do_gvec_op2_ah_fpst, a->esz, a->q, a->rd, a->rn, 0,
+      s->fpcr_ah && dc_isar_feature(aa64_rpres, s) ? f_frsqrte_rpres : f_frsqrte)
 
 static bool trans_FCVTL_v(DisasContext *s, arg_qrr_e *a)
 {
diff --git a/target/arm/tcg/translate-sve.c b/target/arm/tcg/translate-sve.c
index 26bdda8f96e..454f7ff9008 100644
--- a/target/arm/tcg/translate-sve.c
+++ b/target/arm/tcg/translate-sve.c
@@ -3626,13 +3626,25 @@  static gen_helper_gvec_2_ptr * const frecpe_fns[] = {
     NULL,                     gen_helper_gvec_frecpe_h,
     gen_helper_gvec_frecpe_s, gen_helper_gvec_frecpe_d,
 };
-TRANS_FEAT(FRECPE, aa64_sve, gen_gvec_fpst_ah_arg_zz, frecpe_fns[a->esz], a, 0)
+static gen_helper_gvec_2_ptr * const frecpe_rpres_fns[] = {
+    NULL,                           gen_helper_gvec_frecpe_h,
+    gen_helper_gvec_frecpe_rpres_s, gen_helper_gvec_frecpe_d,
+};
+TRANS_FEAT(FRECPE, aa64_sve, gen_gvec_fpst_ah_arg_zz,
+           s->fpcr_ah && dc_isar_feature(aa64_rpres, s) ?
+           frecpe_rpres_fns[a->esz] : frecpe_fns[a->esz], a, 0)
 
 static gen_helper_gvec_2_ptr * const frsqrte_fns[] = {
     NULL,                      gen_helper_gvec_frsqrte_h,
     gen_helper_gvec_frsqrte_s, gen_helper_gvec_frsqrte_d,
 };
-TRANS_FEAT(FRSQRTE, aa64_sve, gen_gvec_fpst_ah_arg_zz, frsqrte_fns[a->esz], a, 0)
+static gen_helper_gvec_2_ptr * const frsqrte_rpres_fns[] = {
+    NULL,                            gen_helper_gvec_frsqrte_h,
+    gen_helper_gvec_frsqrte_rpres_s, gen_helper_gvec_frsqrte_d,
+};
+TRANS_FEAT(FRSQRTE, aa64_sve, gen_gvec_fpst_ah_arg_zz,
+           s->fpcr_ah && dc_isar_feature(aa64_rpres, s) ?
+           frsqrte_rpres_fns[a->esz] : frsqrte_fns[a->esz], a, 0)
 
 /*
  *** SVE Floating Point Compare with Zero Group
diff --git a/target/arm/tcg/vec_helper.c b/target/arm/tcg/vec_helper.c
index c720b435d58..b369c9f45b3 100644
--- a/target/arm/tcg/vec_helper.c
+++ b/target/arm/tcg/vec_helper.c
@@ -1237,10 +1237,12 @@  void HELPER(NAME)(void *vd, void *vn, float_status *stat, uint32_t desc)  \
 
 DO_2OP(gvec_frecpe_h, helper_recpe_f16, float16)
 DO_2OP(gvec_frecpe_s, helper_recpe_f32, float32)
+DO_2OP(gvec_frecpe_rpres_s, helper_recpe_rpres_f32, float32)
 DO_2OP(gvec_frecpe_d, helper_recpe_f64, float64)
 
 DO_2OP(gvec_frsqrte_h, helper_rsqrte_f16, float16)
 DO_2OP(gvec_frsqrte_s, helper_rsqrte_f32, float32)
+DO_2OP(gvec_frsqrte_rpres_s, helper_rsqrte_rpres_f32, float32)
 DO_2OP(gvec_frsqrte_d, helper_rsqrte_f64, float64)
 
 DO_2OP(gvec_vrintx_h, float16_round_to_int, float16)
diff --git a/target/arm/vfp_helper.c b/target/arm/vfp_helper.c
index 50a8a659577..1b7ecc14621 100644
--- a/target/arm/vfp_helper.c
+++ b/target/arm/vfp_helper.c
@@ -839,7 +839,11 @@  uint32_t HELPER(recpe_f16)(uint32_t input, float_status *fpst)
     return make_float16(f16_val);
 }
 
-float32 HELPER(recpe_f32)(float32 input, float_status *fpst)
+/*
+ * FEAT_RPRES means the f32 FRECPE has an "increased precision" variant
+ * which is used when FPCR.AH == 1.
+ */
+static float32 do_recpe_f32(float32 input, float_status *fpst, bool rpres)
 {
     float32 f32 = float32_squash_input_denormal(input, fpst);
     uint32_t f32_val = float32_val(f32);
@@ -888,6 +892,16 @@  float32 HELPER(recpe_f32)(float32 input, float_status *fpst)
     return make_float32(f32_val);
 }
 
+float32 HELPER(recpe_f32)(float32 input, float_status *fpst)
+{
+    return do_recpe_f32(input, fpst, false);
+}
+
+float32 HELPER(recpe_rpres_f32)(float32 input, float_status *fpst)
+{
+    return do_recpe_f32(input, fpst, true);
+}
+
 float64 HELPER(recpe_f64)(float64 input, float_status *fpst)
 {
     float64 f64 = float64_squash_input_denormal(input, fpst);
@@ -1033,7 +1047,11 @@  uint32_t HELPER(rsqrte_f16)(uint32_t input, float_status *s)
     return make_float16(val);
 }
 
-float32 HELPER(rsqrte_f32)(float32 input, float_status *s)
+/*
+ * FEAT_RPRES means the f32 FRSQRTE has an "increased precision" variant
+ * which is used when FPCR.AH == 1.
+ */
+static float32 do_rsqrte_f32(float32 input, float_status *s, bool rpres)
 {
     float32 f32 = float32_squash_input_denormal(input, s);
     uint32_t val = float32_val(f32);
@@ -1078,6 +1096,16 @@  float32 HELPER(rsqrte_f32)(float32 input, float_status *s)
     return make_float32(val);
 }
 
+float32 HELPER(rsqrte_f32)(float32 input, float_status *s)
+{
+    return do_rsqrte_f32(input, s, false);
+}
+
+float32 HELPER(rsqrte_rpres_f32)(float32 input, float_status *s)
+{
+    return do_rsqrte_f32(input, s, true);
+}
+
 float64 HELPER(rsqrte_f64)(float64 input, float_status *s)
 {
     float64 f64 = float64_squash_input_denormal(input, s);