[Qemu-devel] [PATCH v2 18/18] target-s390x: Use the new deposit and extract ops

[Richard Henderson <rth@twiddle.net>]

Use the new primitives for RISBG.

Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 target-s390x/translate.c | 34 ++++++++++++++++++++++------------
 1 file changed, 22 insertions(+), 12 deletions(-)

diff --git a/target-s390x/translate.c b/target-s390x/translate.c
index 02bc705..6cebb7e 100644
--- a/target-s390x/translate.c
+++ b/target-s390x/translate.c
@@ -3134,20 +3134,26 @@ static ExitStatus op_risbg(DisasContext *s, DisasOps *o)
         }
     }
 
-    /* In some cases we can implement this with deposit, which can be more
-       efficient on some hosts.  */
-    if (~mask == imask && i3 <= i4) {
-        if (s->fields->op2 == 0x5d) {
-            i3 += 32, i4 += 32;
-        }
+    len = i4 - i3 + 1;
+    pos = 63 - i4;
+    rot = i5 & 63;
+    if (s->fields->op2 == 0x5d) {
+        pos += 32;
+    }
+
+    /* In some cases we can implement this with extract.  */
+    if (imask == 0 && pos == 0 && len > 0 && rot + len <= 64) {
+        tcg_gen_extract_i64(o->out, o->in2, rot, len);
+        return NO_EXIT;
+    }
+
+    /* In some cases we can implement this with deposit.  */
+    if (len > 0 && (imask == 0 || ~mask == imask)) {
         /* Note that we rotate the bits to be inserted to the lsb, not to
            the position as described in the PoO.  */
-        len = i4 - i3 + 1;
-        pos = 63 - i4;
-        rot = (i5 - pos) & 63;
+        rot = (rot - pos) & 63;
     } else {
-        pos = len = -1;
-        rot = i5 & 63;
+        pos = -1;
     }
 
     /* Rotate the input as necessary.  */
@@ -3155,7 +3161,11 @@ static ExitStatus op_risbg(DisasContext *s, DisasOps *o)
 
     /* Insert the selected bits into the output.  */
     if (pos >= 0) {
-        tcg_gen_deposit_i64(o->out, o->out, o->in2, pos, len);
+        if (imask == 0) {
+            tcg_gen_deposit_z_i64(o->out, o->in2, pos, len);
+        } else {
+            tcg_gen_deposit_i64(o->out, o->out, o->in2, pos, len);
+        }
     } else if (imask == 0) {
         tcg_gen_andi_i64(o->out, o->in2, mask);
     } else {
-- 
2.7.4