1 files changed, 79 insertions, 0 deletions
diff --git a/src/cmd/dist/arm.c b/src/cmd/dist/arm.c
new file mode 100644
index 000000000..dafc5c1c2
--- /dev/null
+++ b/src/cmd/dist/arm.c
@@ -0,0 +1,79 @@
+// Copyright 2012 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "a.h"
+
+#ifndef __ARMEL__
+char *
+xgetgoarm(void)
+{
+	return "6";
+}
+#else
+static void useVFPv3(void);
+static void useVFPv1(void);
+
+char *
+xgetgoarm(void)
+{
+#if defined(__NetBSD__) || defined(__FreeBSD__)
+	// NetBSD has buggy support for VFPv2 (incorrect inexact, 
+	// denormial, and NaN handling). When GOARM=6, some of our
+	// math tests fails on Raspberry Pi.
+	// Thus we return "5" here for safety, the user is free
+	// to override.
+	// Note: using GOARM=6 with cgo can trigger a kernel assertion
+	// failure and crash NetBSD/evbarm kernel.
+	// FreeBSD also have broken VFP support, so disable VFP also
+	// on FreeBSD.
+	return "5";
+#endif
+	if(xtryexecfunc(useVFPv3))
+		return "7";
+	else if(xtryexecfunc(useVFPv1))
+		return "6";
+	return "5";
+}
+
+static void
+useVFPv3(void)
+{
+	// try to run VFPv3-only "vmov.f64 d0, #112" instruction
+	// we can't use that instruction directly, because we
+	// might be compiling with a soft-float only toolchain.
+	//
+	// some newer toolchains are configured to use thumb
+	// by default, so we need to do some mode changing magic
+	// here.
+	// We can use "bx pc; nop" here, but GNU as(1) insists
+	// on warning us
+	// "use of r15 in bx in ARM mode is not really useful"
+	// so we workaround that by using "bx r0"
+	__asm__ __volatile__ ("mov r0, pc");
+	__asm__ __volatile__ ("bx r0");
+	__asm__ __volatile__ (".word 0xeeb70b00"); // vmov.f64 d0, #112
+	__asm__ __volatile__ (".word 0xe12fff1e"); // bx lr
+}
+
+static void
+useVFPv1(void)
+{
+	// try to run "vmov.f64 d0, d0" instruction
+	// we can't use that instruction directly, because we
+	// might be compiling with a soft-float only toolchain
+	//
+	// some newer toolchains are configured to use thumb
+	// by default, so we need to do some mode changing magic
+	// here.
+	// We can use "bx pc; nop" here, but GNU as(1) insists
+	// on warning us
+	// "use of r15 in bx in ARM mode is not really useful"
+	// so we workaround that by using "bx r0"
+	__asm__ __volatile__ ("mov r0, pc");
+	__asm__ __volatile__ ("bx r0");
+	__asm__ __volatile__ (".word 0xeeb00b40"); // vomv.f64 d0, d0
+	__asm__ __volatile__ (".word 0xe12fff1e"); // bx lr
+}
+
+#endif