Fast inverse square root in Golang

Q_rsqrt.go

// The Fast Inverse Square Root code in the game "Quake"
// translated from C
// Reference: https://en.wikipedia.org/wiki/Fast_inverse_square_root

package main

import (
	"fmt"
	"unsafe"
)

func Q_rsqrt(number float32) float32 {
	var i int32
	var x2, y float32
	const threehalfs float32 = 1.5
	x2 = number * 0.5
	y = number
	i = *(*int32)(unsafe.Pointer(&y))
	i = 0x5F3759DF - (i >> 1)
	y = *(*float32)(unsafe.Pointer(&i))
	y = y * (threehalfs - (x2 * y * y))
	// y = y * (theehalfs - (x2 * y * y))
	return y
}

func main() {
	x := Q_rsqrt(2)
	fmt.Printf("%.10f", 1/x)
}