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// 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
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