[src/trunk]: src/sys/arch/powerpc/powerpc As a tiny optimization, rearrange c...

[rin <rin%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/d2cb8bd77c71
branches:  trunk
changeset: 366611:d2cb8bd77c71
user:      rin <rin%NetBSD.org@localhost>
date:      Thu Jun 02 00:32:14 2022 +0000

description:
As a tiny optimization, rearrange cases as follows:

(1) load/store of format D (base + disp)
(2) load/store of format X (base + index)
(3) lmw and stmw

For clang-compiled userland (*), their frequencies are roughly,
(1) > (2) >> (3) ~ 0.

Improvement should be minor; we are already trapped in the alignment
fault handler.

(*) clang unconditionally emits unaligned memory access for powerpc.
    Undocumented -disable-ppc-unaligned option does not work...

diffstat:

 sys/arch/powerpc/powerpc/fix_unaligned.c |  136 +++++++++++++++---------------
 1 files changed, 68 insertions(+), 68 deletions(-)

diffs (168 lines):

diff -r 93b53d7864b0 -r d2cb8bd77c71 sys/arch/powerpc/powerpc/fix_unaligned.c
--- a/sys/arch/powerpc/powerpc/fix_unaligned.c  Thu Jun 02 00:12:20 2022 +0000
+++ b/sys/arch/powerpc/powerpc/fix_unaligned.c  Thu Jun 02 00:32:14 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: fix_unaligned.c,v 1.1 2022/05/30 13:58:51 rin Exp $    */
+/*     $NetBSD: fix_unaligned.c,v 1.2 2022/06/02 00:32:14 rin Exp $    */
 
 /*
  * Copyright (c) 2022 The NetBSD Foundation, Inc.
@@ -51,7 +51,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: fix_unaligned.c,v 1.1 2022/05/30 13:58:51 rin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: fix_unaligned.c,v 1.2 2022/06/02 00:32:14 rin Exp $");
 
 #include "opt_ddb.h"
 #include "opt_ppcarch.h"
@@ -187,27 +187,55 @@
        int flags;
 
        switch (insn->i_any.i_opcd) {
-       case OPC_LMW:
-               UA_EVCNT_INCR(lmw);
-#ifdef FIX_UNALIGNED_LSTMW
+       case OPC_LWZ:
+               UA_EVCNT_INCR(lwz);
                flags = UAF_LOAD;
-               if (do_lstmw(tf, insn, flags))
-                       goto fault;
-               return false;
-#else
-               goto unknown;
-#endif
+               break;
+
+       case OPC_LWZU:
+               UA_EVCNT_INCR(lwzu);
+               flags = UAF_LOAD | UAF_UPDATE;
+               break;
+
+       case OPC_STW:
+               UA_EVCNT_INCR(stw);
+               flags = UAF_STORE;
+               break;
+
+       case OPC_STWU:
+               UA_EVCNT_INCR(stwu);
+               flags = UAF_STORE | UAF_UPDATE;
+               break;
+
+       case OPC_LHZ:
+               UA_EVCNT_INCR(lhz);
+               flags = UAF_LOAD | UAF_HALF;
+               break;
 
-       case OPC_STMW:
-               UA_EVCNT_INCR(stmw);
-#ifdef FIX_UNALIGNED_LSTMW
-               flags = UAF_STORE;
-               if (do_lstmw(tf, insn, flags))
-                       goto fault;
-               return false;
-#else
-               goto unknown;
-#endif
+       case OPC_LHZU:
+               UA_EVCNT_INCR(lhzu);
+               flags = UAF_LOAD | UAF_HALF | UAF_UPDATE;
+               break;
+
+       case OPC_LHA:
+               UA_EVCNT_INCR(lha);
+               flags = UAF_LOAD | UAF_HALF | UAF_ALGEBRA;
+               break;
+
+       case OPC_LHAU:
+               UA_EVCNT_INCR(lhau);
+               flags = UAF_LOAD | UAF_HALF | UAF_ALGEBRA | UAF_UPDATE;
+               break;
+
+       case OPC_STH:
+               UA_EVCNT_INCR(sth);
+               flags = UAF_STORE | UAF_HALF;
+               break;
+
+       case OPC_STHU:
+               UA_EVCNT_INCR(sthu);
+               flags = UAF_STORE | UAF_HALF | UAF_UPDATE;
+               break;
 
        case OPC_integer_31:
                switch (insn->i_x.i_xo) {
@@ -287,55 +315,27 @@
                }
                break;
 
-       case OPC_LWZ:
-               UA_EVCNT_INCR(lwz);
+       case OPC_LMW:
+               UA_EVCNT_INCR(lmw);
+#ifdef FIX_UNALIGNED_LSTMW
                flags = UAF_LOAD;
-               break;
-
-       case OPC_LWZU:
-               UA_EVCNT_INCR(lwzu);
-               flags = UAF_LOAD | UAF_UPDATE;
-               break;
-
-       case OPC_STW:
-               UA_EVCNT_INCR(stw);
-               flags = UAF_STORE;
-               break;
-
-       case OPC_STWU:
-               UA_EVCNT_INCR(stwu);
-               flags = UAF_STORE | UAF_UPDATE;
-               break;
-
-       case OPC_LHZ:
-               UA_EVCNT_INCR(lhz);
-               flags = UAF_LOAD | UAF_HALF;
-               break;
+               if (do_lstmw(tf, insn, flags))
+                       goto fault;
+               return false;
+#else
+               goto unknown;
+#endif
 
-       case OPC_LHZU:
-               UA_EVCNT_INCR(lhzu);
-               flags = UAF_LOAD | UAF_HALF | UAF_UPDATE;
-               break;
-
-       case OPC_LHA:
-               UA_EVCNT_INCR(lha);
-               flags = UAF_LOAD | UAF_HALF | UAF_ALGEBRA;
-               break;
-
-       case OPC_LHAU:
-               UA_EVCNT_INCR(lhau);
-               flags = UAF_LOAD | UAF_HALF | UAF_ALGEBRA | UAF_UPDATE;
-               break;
-
-       case OPC_STH:
-               UA_EVCNT_INCR(sth);
-               flags = UAF_STORE | UAF_HALF;
-               break;
-
-       case OPC_STHU:
-               UA_EVCNT_INCR(sthu);
-               flags = UAF_STORE | UAF_HALF | UAF_UPDATE;
-               break;
+       case OPC_STMW:
+               UA_EVCNT_INCR(stmw);
+#ifdef FIX_UNALIGNED_LSTMW
+               flags = UAF_STORE;
+               if (do_lstmw(tf, insn, flags))
+                       goto fault;
+               return false;
+#else
+               goto unknown;
+#endif
 
        default:
                UA_EVCNT_INCR(unknown);