target/riscv: rvv: Add mask agnostic for vv instructions

According to v-spec, mask agnostic behavior can be either kept as
undisturbed or set elements' bits to all 1s. To distinguish the
difference of mask policies, QEMU should be able to simulate the mask
agnostic behavior as "set mask elements' bits to all 1s".

There are multiple possibility for agnostic elements according to
v-spec. The main intent of this patch-set tries to add option that
can distinguish between mask policies. Setting agnostic elements to
all 1s allows QEMU to express this.

This is the first commit regarding the optional mask agnostic
behavior. Follow-up commits will add this optional behavior
for all rvv instructions.

Signed-off-by: eop Chen <eop.chen@sifive.com>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <165570784143.17634.35095816584573691-1@git.sr.ht>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index ffb1a18873526d0109f90b71da745ba9756a3492..561d7fa92c8cce78b5c1d4417069cd3ea81dcb35 100644 (file)
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -439,6 +439,7 @@ struct RISCVCPUConfig {
     bool ext_zve64f;
     bool ext_zmmul;
     bool rvv_ta_all_1s;
+    bool rvv_ma_all_1s;
 
     uint32_t mvendorid;
     uint64_t marchid;
@@ -596,6 +597,7 @@ FIELD(TB_FLAGS, XL, 20, 2)
 FIELD(TB_FLAGS, PM_MASK_ENABLED, 22, 1)
 FIELD(TB_FLAGS, PM_BASE_ENABLED, 23, 1)
 FIELD(TB_FLAGS, VTA, 24, 1)
+FIELD(TB_FLAGS, VMA, 25, 1)
 
 #ifdef TARGET_RISCV32
 #define riscv_cpu_mxl(env)  ((void)(env), MXL_RV32)

diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 87daf7220f551539afabaea74e9b4beec4ddc875..650574accf0ab03abe6599ee84cf2a3c587f3d53 100644 (file)
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -68,6 +68,8 @@ void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong *pc,
         flags = FIELD_DP32(flags, TB_FLAGS, VL_EQ_VLMAX, vl_eq_vlmax);
         flags = FIELD_DP32(flags, TB_FLAGS, VTA,
                     FIELD_EX64(env->vtype, VTYPE, VTA));
+        flags = FIELD_DP32(flags, TB_FLAGS, VMA,
+                    FIELD_EX64(env->vtype, VTYPE, VMA));
     } else {
         flags = FIELD_DP32(flags, TB_FLAGS, VILL, 1);
     }

diff --git a/target/riscv/insn_trans/trans_rvv.c.inc b/target/riscv/insn_trans/trans_rvv.c.inc
index 6c091824b6bce5a275dc1340b785df1fad50fee1..5ec113f6fd3bd231fe141fc74857199bfb44c841 100644 (file)
--- a/target/riscv/insn_trans/trans_rvv.c.inc
+++ b/target/riscv/insn_trans/trans_rvv.c.inc
@@ -1247,6 +1247,7 @@ do_opivv_gvec(DisasContext *s, arg_rmrr *a, GVecGen3Fn *gvec_fn,
         data = FIELD_DP32(data, VDATA, VM, a->vm);
         data = FIELD_DP32(data, VDATA, LMUL, s->lmul);
         data = FIELD_DP32(data, VDATA, VTA, s->vta);
+        data = FIELD_DP32(data, VDATA, VMA, s->vma);
         tcg_gen_gvec_4_ptr(vreg_ofs(s, a->rd), vreg_ofs(s, 0),
                            vreg_ofs(s, a->rs1), vreg_ofs(s, a->rs2),
                            cpu_env, s->cfg_ptr->vlen / 8,
@@ -1545,6 +1546,7 @@ static bool do_opivv_widen(DisasContext *s, arg_rmrr *a,
         data = FIELD_DP32(data, VDATA, VM, a->vm);
         data = FIELD_DP32(data, VDATA, LMUL, s->lmul);
         data = FIELD_DP32(data, VDATA, VTA, s->vta);
+        data = FIELD_DP32(data, VDATA, VMA, s->vma);
         tcg_gen_gvec_4_ptr(vreg_ofs(s, a->rd), vreg_ofs(s, 0),
                            vreg_ofs(s, a->rs1),
                            vreg_ofs(s, a->rs2),
@@ -1627,6 +1629,7 @@ static bool do_opiwv_widen(DisasContext *s, arg_rmrr *a,
         data = FIELD_DP32(data, VDATA, VM, a->vm);
         data = FIELD_DP32(data, VDATA, LMUL, s->lmul);
         data = FIELD_DP32(data, VDATA, VTA, s->vta);
+        data = FIELD_DP32(data, VDATA, VMA, s->vma);
         tcg_gen_gvec_4_ptr(vreg_ofs(s, a->rd), vreg_ofs(s, 0),
                            vreg_ofs(s, a->rs1),
                            vreg_ofs(s, a->rs2),

diff --git a/target/riscv/internals.h b/target/riscv/internals.h
index 193ce57a6dc0db50c815ac045886d9d475eccb48..5620fbffb6e2b4df8a5621cb37ddc80acab1d9bb 100644 (file)
--- a/target/riscv/internals.h
+++ b/target/riscv/internals.h
@@ -26,8 +26,9 @@ FIELD(VDATA, VM, 0, 1)
 FIELD(VDATA, LMUL, 1, 3)
 FIELD(VDATA, VTA, 4, 1)
 FIELD(VDATA, VTA_ALL_1S, 5, 1)
-FIELD(VDATA, NF, 6, 4)
-FIELD(VDATA, WD, 6, 1)
+FIELD(VDATA, VMA, 6, 1)
+FIELD(VDATA, NF, 7, 4)
+FIELD(VDATA, WD, 7, 1)
 
 /* float point classify helpers */
 target_ulong fclass_h(uint64_t frs1);

diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index 76da8db8a773cb82707f7a6839f953ed295bfe88..8925a44c6e77cd32201e041293d3cb884a4b5e7f 100644 (file)
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -95,6 +95,7 @@ typedef struct DisasContext {
     int8_t lmul;
     uint8_t sew;
     uint8_t vta;
+    uint8_t vma;
     bool cfg_vta_all_1s;
     target_ulong vstart;
     bool vl_eq_vlmax;
@@ -1121,6 +1122,7 @@ static void riscv_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs)
     ctx->sew = FIELD_EX32(tb_flags, TB_FLAGS, SEW);
     ctx->lmul = sextract32(FIELD_EX32(tb_flags, TB_FLAGS, LMUL), 0, 3);
     ctx->vta = FIELD_EX32(tb_flags, TB_FLAGS, VTA) && cpu->cfg.rvv_ta_all_1s;
+    ctx->vma = FIELD_EX32(tb_flags, TB_FLAGS, VMA) && cpu->cfg.rvv_ma_all_1s;
     ctx->cfg_vta_all_1s = cpu->cfg.rvv_ta_all_1s;
     ctx->vstart = env->vstart;
     ctx->vl_eq_vlmax = FIELD_EX32(tb_flags, TB_FLAGS, VL_EQ_VLMAX);

diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c
index a96fc49c71e33442126b95c7595615d5876c7a7a..de895050e0789e47098f3198156985d254f863a7 100644 (file)
--- a/target/riscv/vector_helper.c
+++ b/target/riscv/vector_helper.c
@@ -127,6 +127,11 @@ static inline uint32_t vext_vta(uint32_t desc)
     return FIELD_EX32(simd_data(desc), VDATA, VTA);
 }
 
+static inline uint32_t vext_vma(uint32_t desc)
+{
+    return FIELD_EX32(simd_data(desc), VDATA, VMA);
+}
+
 static inline uint32_t vext_vta_all_1s(uint32_t desc)
 {
     return FIELD_EX32(simd_data(desc), VDATA, VTA_ALL_1S);
@@ -812,10 +817,13 @@ static void do_vext_vv(void *vd, void *v0, void *vs1, void *vs2,
     uint32_t vl = env->vl;
     uint32_t total_elems = vext_get_total_elems(env, desc, esz);
     uint32_t vta = vext_vta(desc);
+    uint32_t vma = vext_vma(desc);
     uint32_t i;
 
     for (i = env->vstart; i < vl; i++) {
         if (!vm && !vext_elem_mask(v0, i)) {
+            /* set masked-off elements to 1s */
+            vext_set_elems_1s(vd, vma, i * esz, (i + 1) * esz);
             continue;
         }
         fn(vd, vs1, vs2, i);