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      1 // Copyright 2009 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 (
      8 	"runtime/internal/atomic"
      9 	_ "unsafe" // for go:linkname
     10 )
     11 
     12 //go:generate go run wincallback.go
     13 //go:generate go run mkduff.go
     14 //go:generate go run mkfastlog2table.go
     15 
     16 var ticks struct {
     17 	lock mutex
     18 	pad  uint32 // ensure 8-byte alignment of val on 386
     19 	val  uint64
     20 }
     21 
     22 // Note: Called by runtime/pprof in addition to runtime code.
     23 func tickspersecond() int64 {
     24 	r := int64(atomic.Load64(&ticks.val))
     25 	if r != 0 {
     26 		return r
     27 	}
     28 	lock(&ticks.lock)
     29 	r = int64(ticks.val)
     30 	if r == 0 {
     31 		t0 := nanotime()
     32 		c0 := cputicks()
     33 		usleep(100 * 1000)
     34 		t1 := nanotime()
     35 		c1 := cputicks()
     36 		if t1 == t0 {
     37 			t1++
     38 		}
     39 		r = (c1 - c0) * 1000 * 1000 * 1000 / (t1 - t0)
     40 		if r == 0 {
     41 			r++
     42 		}
     43 		atomic.Store64(&ticks.val, uint64(r))
     44 	}
     45 	unlock(&ticks.lock)
     46 	return r
     47 }
     48 
     49 var envs []string
     50 var argslice []string
     51 
     52 //go:linkname syscall_runtime_envs syscall.runtime_envs
     53 func syscall_runtime_envs() []string { return append([]string{}, envs...) }
     54 
     55 //go:linkname syscall_Getpagesize syscall.Getpagesize
     56 func syscall_Getpagesize() int { return int(physPageSize) }
     57 
     58 //go:linkname os_runtime_args os.runtime_args
     59 func os_runtime_args() []string { return append([]string{}, argslice...) }
     60 
     61 //go:linkname syscall_Exit syscall.Exit
     62 //go:nosplit
     63 func syscall_Exit(code int) {
     64 	exit(int32(code))
     65 }
     66