[src/trunk]: src/lib/libc/arch/arm/misc Add a constructor for EABI to determi...

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

details:   https://anonhg.NetBSD.org/src/rev/c879be062cbd
branches:  trunk
changeset: 784484:c879be062cbd
user:      matt <matt%NetBSD.org@localhost>
date:      Tue Jan 29 19:14:54 2013 +0000

description:
Add a constructor for EABI to determine if a FPU is present on the system.

diffstat:

 lib/libc/arch/arm/misc/arm_initfini.c |  61 +++++++++++++++++++++++++++++++++++
 1 files changed, 61 insertions(+), 0 deletions(-)

diffs (65 lines):

diff -r 0d45268878f8 -r c879be062cbd lib/libc/arch/arm/misc/arm_initfini.c
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/libc/arch/arm/misc/arm_initfini.c     Tue Jan 29 19:14:54 2013 +0000
@@ -0,0 +1,61 @@
+/*-
+ * Copyright (c) 2013 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Matt Thomas of 3am Software Foundry.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+
+__RCSID("$NetBSD: arm_initfini.c,v 1.1 2013/01/29 19:14:54 matt Exp $");
+
+/*
+ * To properly implement setjmp/longjmp for the ARM AAPCS ABI, it has to be
+ * aware of whether there is a FPU is present or not.  Regardless of whether
+ * the hard-float ABI is being used, setjmp needs to save D8-D15.  But it can
+ * only do this if those instructions won't cause an exception.
+ */
+
+#include <sys/param.h>
+#include <sys/sysctl.h>
+
+#include <stdbool.h>
+
+int _libc_arm_fpu_present;
+static bool _libc_aapcs_initialized;
+
+void   _libc_aapcs_init(void) __attribute__((__constructor__, __used__));
+
+void
+_libc_aapcs_init(void)
+{
+       if (_libc_aapcs_initialized)
+               return;
+
+       _libc_aapcs_initialized = true;
+       size_t len = sizeof(_libc_arm_fpu_present);
+       (void)sysctlbyname("machdep.fpu_present", &_libc_arm_fpu_present, &len,
+           NULL, 0);
+}