target/arm: Implement SVE2p1 PTRUE (predicate as counter)

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250704142112.1018902-81-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/target/arm/tcg/sve.decode b/target/arm/tcg/sve.decode
index 389a72d82427a02529de5bd42dd12eac43351aec..3517efb31b39628aab8d308c4604045640a81462 100644 (file)
--- a/target/arm/tcg/sve.decode
+++ b/target/arm/tcg/sve.decode
@@ -730,6 +730,7 @@ PTEST           00100101 01 010000 11 pg:4 0 rn:4 0 0000
 
 # SVE predicate initialize
 PTRUE           00100101 esz:2 01100 s:1 111000 pat:5 0 rd:4
+PTRUE_cnt       00100101 esz:2 1000000111100000010 ...          rd=%pnd
 
 # SVE initialize FFR
 SETFFR          00100101 0010 1100 1001 0000 0000 0000

diff --git a/target/arm/tcg/translate-sve.c b/target/arm/tcg/translate-sve.c
index c93dca224cea19ae1bf5d8322f9fe676cc1f09e7..651b4aa3781b6a1c00330e92d057886caf2a6ff4 100644 (file)
--- a/target/arm/tcg/translate-sve.c
+++ b/target/arm/tcg/translate-sve.c
@@ -1679,6 +1679,22 @@ static bool do_predset(DisasContext *s, int esz, int rd, int pat, bool setflag)
 
 TRANS_FEAT(PTRUE, aa64_sve, do_predset, a->esz, a->rd, a->pat, a->s)
 
+static bool trans_PTRUE_cnt(DisasContext *s, arg_PTRUE_cnt *a)
+{
+    if (!dc_isar_feature(aa64_sme2_or_sve2p1, s)) {
+        return false;
+    }
+    if (sve_access_check(s)) {
+        /* Canonical TRUE is 0 count, invert bit, plus element size. */
+        int val = (1 << 15) | (1 << a->esz);
+
+        /* Write val to the first uint64_t; clear all of the rest. */
+        tcg_gen_gvec_dup_imm(MO_64, pred_full_reg_offset(s, a->rd),
+                             8, size_for_gvec(pred_full_reg_size(s)), val);
+    }
+    return true;
+}
+
 /* Note pat == 31 is #all, to set all elements.  */
 TRANS_FEAT_NONSTREAMING(SETFFR, aa64_sve,
                         do_predset, 0, FFR_PRED_NUM, 31, false)