What version of Go are you using (go version)?

$ go version
go version go1.21.1 darwin/arm64

Does this issue reproduce with the latest release?

Yes.

What operating system and processor architecture are you using (go env)?

Mac M1

What did you do?

package main

import (
	"math"
	"time"
)

func main() {
	period := uint(30)
	x := time.Time{}
	counter := int64(math.Floor(float64(x.Unix()) / float64(period)))
	counter2 := uint64(math.Floor(float64(x.Unix()) / float64(period)))
	println(counter, counter2)
	// Output: -2071186560 0
}

What did you expect to see?

I would've expected counter2 == 18446744071638365056. It does work when running with GOARCH=amd64 go run .