[src/trunk]: src/sys/arch/arm/include Disable arm32 __asm for _byte_swap_u16_...

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

details:   https://anonhg.NetBSD.org/src/rev/834b467625d6
branches:  trunk
changeset: 781417:834b467625d6
user:      matt <matt%NetBSD.org@localhost>
date:      Wed Sep 05 01:03:53 2012 +0000

description:
Disable arm32 __asm for _byte_swap_u16_variable since gcc4.5 produces
decent code for it.  Fixes PR/46898.

diffstat:

 sys/arch/arm/include/byte_swap.h |  11 ++++++-----
 1 files changed, 6 insertions(+), 5 deletions(-)

diffs (30 lines):

diff -r 0862ec52f2e5 -r 834b467625d6 sys/arch/arm/include/byte_swap.h
--- a/sys/arch/arm/include/byte_swap.h  Wed Sep 05 00:22:41 2012 +0000
+++ b/sys/arch/arm/include/byte_swap.h  Wed Sep 05 01:03:53 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: byte_swap.h,v 1.11 2012/07/20 18:53:34 matt Exp $      */
+/*     $NetBSD: byte_swap.h,v 1.12 2012/09/05 01:03:53 matt Exp $      */
 
 /*-
  * Copyright (c) 1997, 1999, 2002 The NetBSD Foundation, Inc.
@@ -94,15 +94,16 @@
                __asm("rev16\t%0, %1" : "=r" (v) : "0" (v));
                return v;
        }
-#elif !defined(__thumb__)
+#elif !defined(__thumb__) && 0 /* gcc produces decent code for this */
        if (!__builtin_constant_p(v)) {
+               uint32_t v0 = v;
                __asm volatile(
                        "mov    %0, %1, ror #8\n"
                        "orr    %0, %0, %0, lsr #16\n"
                        "bic    %0, %0, %0, lsl #16"
-               : "=&r" (v)
-               : "0" (v));
-               return (v);
+               : "=&r" (v0)
+               : "0" (v0));
+               return v0;
        }
 #endif
        v &= 0xffff;