diff mbox

[v2,07/11] target-arm: Recognize SXTB, SXTH, SXTW, ASR

Message ID 1441216660-8717-8-git-send-email-rth@twiddle.net
State New
Headers show

Commit Message

Richard Henderson Sept. 2, 2015, 5:57 p.m. UTC 
... as aliases of SBFM, and special-case them.

Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 target-arm/translate-a64.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

Comments

Peter Maydell Sept. 7, 2015, 5:47 p.m. UTC | #1 
On 2 September 2015 at 18:57, Richard Henderson <rth@twiddle.net> wrote:
> ... as aliases of SBFM, and special-case them.
>
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

(Not a fan of commit messages that start a sentence in the Subject
and continue it in the body.)

thanks
-- PMM
diff mbox

Patch

diff --git a/target-arm/translate-a64.c b/target-arm/translate-a64.c
index a6e5ccd..74dd0f8 100644
--- a/target-arm/translate-a64.c
+++ b/target-arm/translate-a64.c
@@ -2999,7 +2999,28 @@  static void disas_bitfield(DisasContext *s, uint32_t insn)
     tcg_rd = cpu_reg(s, rd);
     tcg_tmp = read_cpu_reg(s, rn, sf);
 
-    /* OPTME: probably worth recognizing common cases of ext{8,16,32}{u,s} */
+    /* Recognize the common aliases.  */
+    if (opc == 0) { /* SBFM */
+        if (ri == 0) {
+            if (si == 7) { /* SXTB */
+                tcg_gen_ext8s_i64(tcg_rd, tcg_tmp);
+                goto done;
+            } else if (si == 15) { /* SXTH */
+                tcg_gen_ext16s_i64(tcg_rd, tcg_tmp);
+                goto done;
+            } else if (si == 31) { /* SXTW */
+                tcg_gen_ext32s_i64(tcg_rd, tcg_tmp);
+                goto done;
+            }
+        }
+        if (si == 63 || (si == 31 && ri <= si)) { /* ASR */
+            if (si == 31) {
+                tcg_gen_ext32s_i64(tcg_tmp, tcg_tmp);
+            }
+            tcg_gen_sari_i64(tcg_rd, tcg_tmp, ri);
+            goto done;
+        }
+    }
 
     if (opc != 1) { /* SBFM or UBFM */
         tcg_gen_movi_i64(tcg_rd, 0);
@@ -3024,6 +3045,7 @@  static void disas_bitfield(DisasContext *s, uint32_t insn)
         tcg_gen_sari_i64(tcg_rd, tcg_rd, 64 - (pos + len));
     }
 
+ done:
     if (!sf) { /* zero extend final result */
         tcg_gen_ext32u_i64(tcg_rd, tcg_rd);
     }