CVS commit: [netbsd-6] src/sys/arch/arm/include

[Jeff Rizzo]

Module Name:    src
Committed By:   riz
Date:           Thu Sep 13 20:28:16 UTC 2012

Modified Files:
        src/sys/arch/arm/include [netbsd-6]: byte_swap.h

Log Message:
Pull up following revision(s) (requested by martin in ticket #542):
        sys/arch/arm/include/byte_swap.h: revision 1.12
Disable arm32 __asm for _byte_swap_u16_variable since gcc4.5 produces
decent code for it.  Fixes PR/46898.


To generate a diff of this commit:
cvs rdiff -u -r1.8 -r1.8.40.1 src/sys/arch/arm/include/byte_swap.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.


Modified files:

Index: src/sys/arch/arm/include/byte_swap.h
diff -u src/sys/arch/arm/include/byte_swap.h:1.8 src/sys/arch/arm/include/byte_swap.h:1.8.40.1
--- src/sys/arch/arm/include/byte_swap.h:1.8	Mon Apr 28 20:23:14 2008
+++ src/sys/arch/arm/include/byte_swap.h	Thu Sep 13 20:28:15 2012
@@ -1,4 +1,4 @@
-/*	$NetBSD: byte_swap.h,v 1.8 2008/04/28 20:23:14 martin Exp $	*/
+/*	$NetBSD: byte_swap.h,v 1.8.40.1 2012/09/13 20:28:15 riz Exp $	*/
 
 /*-
  * Copyright (c) 1997, 1999, 2002 The NetBSD Foundation, Inc.
@@ -40,16 +40,20 @@ __BEGIN_DECLS
 static __inline uint32_t
 __byte_swap_u32_variable(uint32_t v)
 {
-#ifdef _ARM_ARCH_6
-	__asm("rev\t%0, %1" : "=r" (v) : "0" (v));
-#else
 	uint32_t t1;
 
+#ifdef _ARM_ARCH_6
+	if (!__builtin_constant_p(v)) {
+		__asm("rev\t%0, %1" : "=r" (v) : "0" (v));
+		return v;
+	}
+#endif
+
 	t1 = v ^ ((v << 16) | (v >> 16));
 	t1 &= 0xff00ffffU;
 	v = (v >> 8) | (v << 24);
 	v ^= (t1 >> 8);
-#endif
+
 	return (v);
 }
 
@@ -59,18 +63,24 @@ __byte_swap_u16_variable(uint16_t v)
 {
 
 #ifdef _ARM_ARCH_6
-	__asm("rev16\t%0, %1" : "=r" (v) : "0" (v));
-#elif !defined(__thumb__)
-	__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));
-#else
+	if (!__builtin_constant_p(v)) {
+		__asm("rev16\t%0, %1" : "=r" (v) : "0" (v));
+		return v;
+	}
+#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" (v0)
+		: "0" (v0));
+		return v0;
+	}
+#endif
 	v &= 0xffff;
 	v = (v >> 8) | (v << 8);
-#endif
 
 	return (v);
 }