s390x/tcg: Implement VECTOR SUBTRACT COMPUTE BORROW INDICATION

Let's keep it simple for now and handle 8/16 bit elements via helpers.
Especially for 8/16, we could come up with some bit tricks.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>

1 files changed, 52 insertions, 0 deletions

diff --git a/target/s390x/translate_vx.inc.c b/target/s390x/translate_vx.inc.c
index 5f53ae7ec5..b7052f73f8 100644
--- a/target/s390x/translate_vx.inc.c
+++ b/target/s390x/translate_vx.inc.c
@@ -2140,3 +2140,55 @@ static DisasJumpType op_vs(DisasContext *s, DisasOps *o)
                   get_field(s->fields, v3));
     return DISAS_NEXT;
 }
+
+static void gen_scbi_i32(TCGv_i32 d, TCGv_i32 a, TCGv_i32 b)
+{
+    tcg_gen_setcond_i32(TCG_COND_LTU, d, a, b);
+}
+
+static void gen_scbi_i64(TCGv_i64 d, TCGv_i64 a, TCGv_i64 b)
+{
+    tcg_gen_setcond_i64(TCG_COND_LTU, d, a, b);
+}
+
+static void gen_scbi2_i64(TCGv_i64 dl, TCGv_i64 dh, TCGv_i64 al,
+                          TCGv_i64 ah, TCGv_i64 bl, TCGv_i64 bh)
+{
+    TCGv_i64 th = tcg_temp_new_i64();
+    TCGv_i64 tl = tcg_temp_new_i64();
+    TCGv_i64 zero = tcg_const_i64(0);
+
+    tcg_gen_sub2_i64(tl, th, al, zero, bl, zero);
+    tcg_gen_andi_i64(th, th, 1);
+    tcg_gen_sub2_i64(tl, th, ah, zero, th, zero);
+    tcg_gen_sub2_i64(tl, th, tl, th, bh, zero);
+    tcg_gen_andi_i64(dl, th, 1);
+    tcg_gen_mov_i64(dh, zero);
+
+    tcg_temp_free_i64(th);
+    tcg_temp_free_i64(tl);
+    tcg_temp_free_i64(zero);
+}
+
+static DisasJumpType op_vscbi(DisasContext *s, DisasOps *o)
+{
+    const uint8_t es = get_field(s->fields, m4);
+    static const GVecGen3 g[4] = {
+        { .fno = gen_helper_gvec_vscbi8, },
+        { .fno = gen_helper_gvec_vscbi16, },
+        { .fni4 = gen_scbi_i32, },
+        { .fni8 = gen_scbi_i64, },
+    };
+
+    if (es > ES_128) {
+        gen_program_exception(s, PGM_SPECIFICATION);
+        return DISAS_NORETURN;
+    } else if (es == ES_128) {
+        gen_gvec128_3_i64(gen_scbi2_i64, get_field(s->fields, v1),
+                          get_field(s->fields, v2), get_field(s->fields, v3));
+        return DISAS_NEXT;
+    }
+    gen_gvec_3(get_field(s->fields, v1), get_field(s->fields, v2),
+               get_field(s->fields, v3), &g[es]);
+    return DISAS_NEXT;
+}