Source file src/runtime/os_freebsd_arm.go

     1	// Copyright 2012 The Go Authors. All rights reserved.
     2	// Use of this source code is governed by a BSD-style
     3	// license that can be found in the LICENSE file.
     4	
     5	package runtime
     6	
     7	import "internal/cpu"
     8	
     9	const (
    10		_HWCAP_VFP   = 1 << 6
    11		_HWCAP_VFPv3 = 1 << 13
    12	)
    13	
    14	func checkgoarm() {
    15		if goarm > 5 && cpu.HWCap&_HWCAP_VFP == 0 {
    16			print("runtime: this CPU has no floating point hardware, so it cannot run\n")
    17			print("this GOARM=", goarm, " binary. Recompile using GOARM=5.\n")
    18			exit(1)
    19		}
    20		if goarm > 6 && cpu.HWCap&_HWCAP_VFPv3 == 0 {
    21			print("runtime: this CPU has no VFPv3 floating point hardware, so it cannot run\n")
    22			print("this GOARM=", goarm, " binary. Recompile using GOARM=5 or GOARM=6.\n")
    23			exit(1)
    24		}
    25	
    26		// osinit not called yet, so ncpu not set: must use getncpu directly.
    27		if getncpu() > 1 && goarm < 7 {
    28			print("runtime: this system has multiple CPUs and must use\n")
    29			print("atomic synchronization instructions. Recompile using GOARM=7.\n")
    30			exit(1)
    31		}
    32	}
    33	
    34	func archauxv(tag, val uintptr) {
    35		switch tag {
    36		case _AT_HWCAP:
    37			cpu.HWCap = uint(val)
    38		case _AT_HWCAP2:
    39			cpu.HWCap2 = uint(val)
    40		}
    41	}
    42	
    43	//go:nosplit
    44	func cputicks() int64 {
    45		// Currently cputicks() is used in blocking profiler and to seed runtime·fastrand().
    46		// runtime·nanotime() is a poor approximation of CPU ticks that is enough for the profiler.
    47		// TODO: need more entropy to better seed fastrand.
    48		return nanotime()
    49	}
    50	

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