github.com/geraldss/go/src@v0.0.0-20210511222824-ac7d0ebfc235/runtime/os_freebsd_arm.go (about)

     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  	return nanotime()
    48  }